Commit Graph

1480 Commits

Author SHA1 Message Date
Linus Torvalds
5b0e2cb020 powerpc updates for 4.15
Non-highlights:
 
  - Five fixes for the >128T address space handling, both to fix bugs in our
    implementation and to bring the semantics exactly into line with x86.
 
 Highlights:
 
  - Support for a new OPAL call on bare metal machines which gives us a true NMI
    (ie. is not masked by MSR[EE]=0) for debugging etc.
 
  - Support for Power9 DD2 in the CXL driver.
 
  - Improvements to machine check handling so that uncorrectable errors can be
    reported into the generic memory_failure() machinery.
 
  - Some fixes and improvements for VPHN, which is used under PowerVM to notify
    the Linux partition of topology changes.
 
  - Plumbing to enable TM (transactional memory) without suspend on some Power9
    processors (PPC_FEATURE2_HTM_NO_SUSPEND).
 
  - Support for emulating vector loads form cache-inhibited memory, on some
    Power9 revisions.
 
  - Disable the fast-endian switch "syscall" by default (behind a CONFIG), we
    believe it has never had any users.
 
  - A major rework of the API drivers use when initiating and waiting for long
    running operations performed by OPAL firmware, and changes to the
    powernv_flash driver to use the new API.
 
  - Several fixes for the handling of FP/VMX/VSX while processes are using
    transactional memory.
 
  - Optimisations of TLB range flushes when using the radix MMU on Power9.
 
  - Improvements to the VAS facility used to access coprocessors on Power9, and
    related improvements to the way the NX crypto driver handles requests.
 
  - Implementation of PMEM_API and UACCESS_FLUSHCACHE for 64-bit.
 
 Thanks to:
   Alexey Kardashevskiy, Alistair Popple, Allen Pais, Andrew Donnellan, Aneesh
   Kumar K.V, Arnd Bergmann, Balbir Singh, Benjamin Herrenschmidt, Breno Leitao,
   Christophe Leroy, Christophe Lombard, Cyril Bur, Frederic Barrat, Gautham R.
   Shenoy, Geert Uytterhoeven, Guilherme G. Piccoli, Gustavo Romero, Haren
   Myneni, Joel Stanley, Kamalesh Babulal, Kautuk Consul, Markus Elfring, Masami
   Hiramatsu, Michael Bringmann, Michael Neuling, Michal Suchanek, Naveen N. Rao,
   Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pedro Miraglia Franco de
   Carvalho, Philippe Bergheaud, Sandipan Das, Seth Forshee, Shriya, Stephen
   Rothwell, Stewart Smith, Sukadev Bhattiprolu, Tyrel Datwyler, Vaibhav Jain,
   Vaidyanathan Srinivasan, William A. Kennington III.
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Merge tag 'powerpc-4.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "A bit of a small release, I suspect in part due to me travelling for
  KS. But my backlog of patches to review is smaller than usual, so I
  think in part folks just didn't send as much this cycle.

  Non-highlights:

   - Five fixes for the >128T address space handling, both to fix bugs
     in our implementation and to bring the semantics exactly into line
     with x86.

  Highlights:

   - Support for a new OPAL call on bare metal machines which gives us a
     true NMI (ie. is not masked by MSR[EE]=0) for debugging etc.

   - Support for Power9 DD2 in the CXL driver.

   - Improvements to machine check handling so that uncorrectable errors
     can be reported into the generic memory_failure() machinery.

   - Some fixes and improvements for VPHN, which is used under PowerVM
     to notify the Linux partition of topology changes.

   - Plumbing to enable TM (transactional memory) without suspend on
     some Power9 processors (PPC_FEATURE2_HTM_NO_SUSPEND).

   - Support for emulating vector loads form cache-inhibited memory, on
     some Power9 revisions.

   - Disable the fast-endian switch "syscall" by default (behind a
     CONFIG), we believe it has never had any users.

   - A major rework of the API drivers use when initiating and waiting
     for long running operations performed by OPAL firmware, and changes
     to the powernv_flash driver to use the new API.

   - Several fixes for the handling of FP/VMX/VSX while processes are
     using transactional memory.

   - Optimisations of TLB range flushes when using the radix MMU on
     Power9.

   - Improvements to the VAS facility used to access coprocessors on
     Power9, and related improvements to the way the NX crypto driver
     handles requests.

   - Implementation of PMEM_API and UACCESS_FLUSHCACHE for 64-bit.

  Thanks to: Alexey Kardashevskiy, Alistair Popple, Allen Pais, Andrew
  Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Balbir Singh, Benjamin
  Herrenschmidt, Breno Leitao, Christophe Leroy, Christophe Lombard,
  Cyril Bur, Frederic Barrat, Gautham R. Shenoy, Geert Uytterhoeven,
  Guilherme G. Piccoli, Gustavo Romero, Haren Myneni, Joel Stanley,
  Kamalesh Babulal, Kautuk Consul, Markus Elfring, Masami Hiramatsu,
  Michael Bringmann, Michael Neuling, Michal Suchanek, Naveen N. Rao,
  Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pedro Miraglia
  Franco de Carvalho, Philippe Bergheaud, Sandipan Das, Seth Forshee,
  Shriya, Stephen Rothwell, Stewart Smith, Sukadev Bhattiprolu, Tyrel
  Datwyler, Vaibhav Jain, Vaidyanathan Srinivasan, and William A.
  Kennington III"

* tag 'powerpc-4.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (151 commits)
  powerpc/64s: Fix Power9 DD2.0 workarounds by adding DD2.1 feature
  powerpc/64s: Fix masking of SRR1 bits on instruction fault
  powerpc/64s: mm_context.addr_limit is only used on hash
  powerpc/64s/radix: Fix 128TB-512TB virtual address boundary case allocation
  powerpc/64s/hash: Allow MAP_FIXED allocations to cross 128TB boundary
  powerpc/64s/hash: Fix fork() with 512TB process address space
  powerpc/64s/hash: Fix 128TB-512TB virtual address boundary case allocation
  powerpc/64s/hash: Fix 512T hint detection to use >= 128T
  powerpc: Fix DABR match on hash based systems
  powerpc/signal: Properly handle return value from uprobe_deny_signal()
  powerpc/fadump: use kstrtoint to handle sysfs store
  powerpc/lib: Implement UACCESS_FLUSHCACHE API
  powerpc/lib: Implement PMEM API
  powerpc/powernv/npu: Don't explicitly flush nmmu tlb
  powerpc/powernv/npu: Use flush_all_mm() instead of flush_tlb_mm()
  powerpc/powernv/idle: Round up latency and residency values
  powerpc/kprobes: refactor kprobe_lookup_name for safer string operations
  powerpc/kprobes: Blacklist emulate_update_regs() from kprobes
  powerpc/kprobes: Do not disable interrupts for optprobes and kprobes_on_ftrace
  powerpc/kprobes: Disable preemption before invoking probe handler for optprobes
  ...
2017-11-16 12:47:46 -08:00
Radim Krčmář
d850a255d5 PPC KVM fixes for 4.14
Just one fix here for a host crash that can occur with HV KVM
 as a result of resizing the guest hashed page table (HPT).
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Merge tag 'kvm-ppc-fixes-4.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc

PPC KVM fixes for 4.14

Just one fix here for a host crash that can occur with HV KVM
as a result of resizing the guest hashed page table (HPT).
2017-11-08 14:08:59 +01:00
Paul Mackerras
38c53af853 KVM: PPC: Book3S HV: Fix exclusion between HPT resizing and other HPT updates
Commit 5e9859699a ("KVM: PPC: Book3S HV: Outline of KVM-HV HPT resizing
implementation", 2016-12-20) added code that tries to exclude any use
or update of the hashed page table (HPT) while the HPT resizing code
is iterating through all the entries in the HPT.  It does this by
taking the kvm->lock mutex, clearing the kvm->arch.hpte_setup_done
flag and then sending an IPI to all CPUs in the host.  The idea is
that any VCPU task that tries to enter the guest will see that the
hpte_setup_done flag is clear and therefore call kvmppc_hv_setup_htab_rma,
which also takes the kvm->lock mutex and will therefore block until
we release kvm->lock.

However, any VCPU that is already in the guest, or is handling a
hypervisor page fault or hypercall, can re-enter the guest without
rechecking the hpte_setup_done flag.  The IPI will cause a guest exit
of any VCPUs that are currently in the guest, but does not prevent
those VCPU tasks from immediately re-entering the guest.

The result is that after resize_hpt_rehash_hpte() has made a HPTE
absent, a hypervisor page fault can occur and make that HPTE present
again.  This includes updating the rmap array for the guest real page,
meaning that we now have a pointer in the rmap array which connects
with pointers in the old rev array but not the new rev array.  In
fact, if the HPT is being reduced in size, the pointer in the rmap
array could point outside the bounds of the new rev array.  If that
happens, we can get a host crash later on such as this one:

[91652.628516] Unable to handle kernel paging request for data at address 0xd0000000157fb10c
[91652.628668] Faulting instruction address: 0xc0000000000e2640
[91652.628736] Oops: Kernel access of bad area, sig: 11 [#1]
[91652.628789] LE SMP NR_CPUS=1024 NUMA PowerNV
[91652.628847] Modules linked in: binfmt_misc vhost_net vhost tap xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_mangle ip6table_security ip6table_raw iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack libcrc32c iptable_mangle iptable_security iptable_raw ebtable_filter ebtables ip6table_filter ip6_tables ses enclosure scsi_transport_sas i2c_opal ipmi_powernv ipmi_devintf i2c_core ipmi_msghandler powernv_op_panel nfsd auth_rpcgss oid_registry nfs_acl lockd grace sunrpc kvm_hv kvm_pr kvm scsi_dh_alua dm_service_time dm_multipath tg3 ptp pps_core [last unloaded: stap_552b612747aec2da355051e464fa72a1_14259]
[91652.629566] CPU: 136 PID: 41315 Comm: CPU 21/KVM Tainted: G           O    4.14.0-1.rc4.dev.gitb27fc5c.el7.centos.ppc64le #1
[91652.629684] task: c0000007a419e400 task.stack: c0000000028d8000
[91652.629750] NIP:  c0000000000e2640 LR: d00000000c36e498 CTR: c0000000000e25f0
[91652.629829] REGS: c0000000028db5d0 TRAP: 0300   Tainted: G           O     (4.14.0-1.rc4.dev.gitb27fc5c.el7.centos.ppc64le)
[91652.629932] MSR:  900000010280b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]>  CR: 44022422  XER: 00000000
[91652.630034] CFAR: d00000000c373f84 DAR: d0000000157fb10c DSISR: 40000000 SOFTE: 1
[91652.630034] GPR00: d00000000c36e498 c0000000028db850 c000000001403900 c0000007b7960000
[91652.630034] GPR04: d0000000117fb100 d000000007ab00d8 000000000033bb10 0000000000000000
[91652.630034] GPR08: fffffffffffffe7f 801001810073bb10 d00000000e440000 d00000000c373f70
[91652.630034] GPR12: c0000000000e25f0 c00000000fdb9400 f000000003b24680 0000000000000000
[91652.630034] GPR16: 00000000000004fb 00007ff7081a0000 00000000000ec91a 000000000033bb10
[91652.630034] GPR20: 0000000000010000 00000000001b1190 0000000000000001 0000000000010000
[91652.630034] GPR24: c0000007b7ab8038 d0000000117fb100 0000000ec91a1190 c000001e6a000000
[91652.630034] GPR28: 00000000033bb100 000000000073bb10 c0000007b7960000 d0000000157fb100
[91652.630735] NIP [c0000000000e2640] kvmppc_add_revmap_chain+0x50/0x120
[91652.630806] LR [d00000000c36e498] kvmppc_book3s_hv_page_fault+0xbb8/0xc40 [kvm_hv]
[91652.630884] Call Trace:
[91652.630913] [c0000000028db850] [c0000000028db8b0] 0xc0000000028db8b0 (unreliable)
[91652.630996] [c0000000028db8b0] [d00000000c36e498] kvmppc_book3s_hv_page_fault+0xbb8/0xc40 [kvm_hv]
[91652.631091] [c0000000028db9e0] [d00000000c36a078] kvmppc_vcpu_run_hv+0xdf8/0x1300 [kvm_hv]
[91652.631179] [c0000000028dbb30] [d00000000c2248c4] kvmppc_vcpu_run+0x34/0x50 [kvm]
[91652.631266] [c0000000028dbb50] [d00000000c220d54] kvm_arch_vcpu_ioctl_run+0x114/0x2a0 [kvm]
[91652.631351] [c0000000028dbbd0] [d00000000c2139d8] kvm_vcpu_ioctl+0x598/0x7a0 [kvm]
[91652.631433] [c0000000028dbd40] [c0000000003832e0] do_vfs_ioctl+0xd0/0x8c0
[91652.631501] [c0000000028dbde0] [c000000000383ba4] SyS_ioctl+0xd4/0x130
[91652.631569] [c0000000028dbe30] [c00000000000b8e0] system_call+0x58/0x6c
[91652.631635] Instruction dump:
[91652.631676] fba1ffe8 fbc1fff0 fbe1fff8 f8010010 f821ffa1 2fa70000 793d0020 e9432110
[91652.631814] 7bbf26e4 7c7e1b78 7feafa14 409e0094 <807f000c> 786326e4 7c6a1a14 93a40008
[91652.631959] ---[ end trace ac85ba6db72e5b2e ]---

To fix this, we tighten up the way that the hpte_setup_done flag is
checked to ensure that it does provide the guarantee that the resizing
code needs.  In kvmppc_run_core(), we check the hpte_setup_done flag
after disabling interrupts and refuse to enter the guest if it is
clear (for a HPT guest).  The code that checks hpte_setup_done and
calls kvmppc_hv_setup_htab_rma() is moved from kvmppc_vcpu_run_hv()
to a point inside the main loop in kvmppc_run_vcpu(), ensuring that
we don't just spin endlessly calling kvmppc_run_core() while
hpte_setup_done is clear, but instead have a chance to block on the
kvm->lock mutex.

Finally we also check hpte_setup_done inside the region in
kvmppc_book3s_hv_page_fault() where the HPTE is locked and we are about
to update the HPTE, and bail out if it is clear.  If another CPU is
inside kvm_vm_ioctl_resize_hpt_commit) and has cleared hpte_setup_done,
then we know that either we are looking at a HPTE
that resize_hpt_rehash_hpte() has not yet processed, which is OK,
or else we will see hpte_setup_done clear and refuse to update it,
because of the full barrier formed by the unlock of the HPTE in
resize_hpt_rehash_hpte() combined with the locking of the HPTE
in kvmppc_book3s_hv_page_fault().

Fixes: 5e9859699a ("KVM: PPC: Book3S HV: Outline of KVM-HV HPT resizing implementation")
Cc: stable@vger.kernel.org # v4.10+
Reported-by: Satheesh Rajendran <satheera@in.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-11-08 15:14:02 +11:00
Nicholas Piggin
6de6638b35 KVM: PPC: Book3S HV: Handle host system reset in guest mode
If the host takes a system reset interrupt while a guest is running,
the CPU must exit the guest before processing the host exception
handler.

After this patch, taking a sysrq+x with a CPU running in a guest
gives a trace like this:

   cpu 0x27: Vector: 100 (System Reset) at [c000000fdf5776f0]
       pc: c008000010158b80: kvmppc_run_core+0x16b8/0x1ad0 [kvm_hv]
       lr: c008000010158b80: kvmppc_run_core+0x16b8/0x1ad0 [kvm_hv]
       sp: c000000fdf577850
      msr: 9000000002803033
     current = 0xc000000fdf4b1e00
     paca    = 0xc00000000fd4d680	 softe: 3	 irq_happened: 0x01
       pid   = 6608, comm = qemu-system-ppc
   Linux version 4.14.0-rc7-01489-g47e1893a404a-dirty #26 SMP
   [c000000fdf577a00] c008000010159dd4 kvmppc_vcpu_run_hv+0x3dc/0x12d0 [kvm_hv]
   [c000000fdf577b30] c0080000100a537c kvmppc_vcpu_run+0x44/0x60 [kvm]
   [c000000fdf577b60] c0080000100a1ae0 kvm_arch_vcpu_ioctl_run+0x118/0x310 [kvm]
   [c000000fdf577c00] c008000010093e98 kvm_vcpu_ioctl+0x530/0x7c0 [kvm]
   [c000000fdf577d50] c000000000357bf8 do_vfs_ioctl+0xd8/0x8c0
   [c000000fdf577df0] c000000000358448 SyS_ioctl+0x68/0x100
   [c000000fdf577e30] c00000000000b220 system_call+0x58/0x6c
   --- Exception: c01 (System Call) at 00007fff76868df0
   SP (7fff7069baf0) is in userspace

Fixes: e36d0a2ed5 ("powerpc/powernv: Implement NMI IPI with OPAL_SIGNAL_SYSTEM_RESET")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-11-06 16:48:06 +11:00
Linus Torvalds
ead751507d License cleanup: add SPDX license identifiers to some files
Many source files in the tree are missing licensing information, which
 makes it harder for compliance tools to determine the correct license.
 
 By default all files without license information are under the default
 license of the kernel, which is GPL version 2.
 
 Update the files which contain no license information with the 'GPL-2.0'
 SPDX license identifier.  The SPDX identifier is a legally binding
 shorthand, which can be used instead of the full boiler plate text.
 
 This patch is based on work done by Thomas Gleixner and Kate Stewart and
 Philippe Ombredanne.
 
 How this work was done:
 
 Patches were generated and checked against linux-4.14-rc6 for a subset of
 the use cases:
  - file had no licensing information it it.
  - file was a */uapi/* one with no licensing information in it,
  - file was a */uapi/* one with existing licensing information,
 
 Further patches will be generated in subsequent months to fix up cases
 where non-standard license headers were used, and references to license
 had to be inferred by heuristics based on keywords.
 
 The analysis to determine which SPDX License Identifier to be applied to
 a file was done in a spreadsheet of side by side results from of the
 output of two independent scanners (ScanCode & Windriver) producing SPDX
 tag:value files created by Philippe Ombredanne.  Philippe prepared the
 base worksheet, and did an initial spot review of a few 1000 files.
 
 The 4.13 kernel was the starting point of the analysis with 60,537 files
 assessed.  Kate Stewart did a file by file comparison of the scanner
 results in the spreadsheet to determine which SPDX license identifier(s)
 to be applied to the file. She confirmed any determination that was not
 immediately clear with lawyers working with the Linux Foundation.
 
 Criteria used to select files for SPDX license identifier tagging was:
  - Files considered eligible had to be source code files.
  - Make and config files were included as candidates if they contained >5
    lines of source
  - File already had some variant of a license header in it (even if <5
    lines).
 
 All documentation files were explicitly excluded.
 
 The following heuristics were used to determine which SPDX license
 identifiers to apply.
 
  - when both scanners couldn't find any license traces, file was
    considered to have no license information in it, and the top level
    COPYING file license applied.
 
    For non */uapi/* files that summary was:
 
    SPDX license identifier                            # files
    ---------------------------------------------------|-------
    GPL-2.0                                              11139
 
    and resulted in the first patch in this series.
 
    If that file was a */uapi/* path one, it was "GPL-2.0 WITH
    Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
 
    SPDX license identifier                            # files
    ---------------------------------------------------|-------
    GPL-2.0 WITH Linux-syscall-note                        930
 
    and resulted in the second patch in this series.
 
  - if a file had some form of licensing information in it, and was one
    of the */uapi/* ones, it was denoted with the Linux-syscall-note if
    any GPL family license was found in the file or had no licensing in
    it (per prior point).  Results summary:
 
    SPDX license identifier                            # files
    ---------------------------------------------------|------
    GPL-2.0 WITH Linux-syscall-note                       270
    GPL-2.0+ WITH Linux-syscall-note                      169
    ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
    ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
    LGPL-2.1+ WITH Linux-syscall-note                      15
    GPL-1.0+ WITH Linux-syscall-note                       14
    ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
    LGPL-2.0+ WITH Linux-syscall-note                       4
    LGPL-2.1 WITH Linux-syscall-note                        3
    ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
    ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
 
    and that resulted in the third patch in this series.
 
  - when the two scanners agreed on the detected license(s), that became
    the concluded license(s).
 
  - when there was disagreement between the two scanners (one detected a
    license but the other didn't, or they both detected different
    licenses) a manual inspection of the file occurred.
 
  - In most cases a manual inspection of the information in the file
    resulted in a clear resolution of the license that should apply (and
    which scanner probably needed to revisit its heuristics).
 
  - When it was not immediately clear, the license identifier was
    confirmed with lawyers working with the Linux Foundation.
 
  - If there was any question as to the appropriate license identifier,
    the file was flagged for further research and to be revisited later
    in time.
 
 In total, over 70 hours of logged manual review was done on the
 spreadsheet to determine the SPDX license identifiers to apply to the
 source files by Kate, Philippe, Thomas and, in some cases, confirmation
 by lawyers working with the Linux Foundation.
 
 Kate also obtained a third independent scan of the 4.13 code base from
 FOSSology, and compared selected files where the other two scanners
 disagreed against that SPDX file, to see if there was new insights.  The
 Windriver scanner is based on an older version of FOSSology in part, so
 they are related.
 
 Thomas did random spot checks in about 500 files from the spreadsheets
 for the uapi headers and agreed with SPDX license identifier in the
 files he inspected. For the non-uapi files Thomas did random spot checks
 in about 15000 files.
 
 In initial set of patches against 4.14-rc6, 3 files were found to have
 copy/paste license identifier errors, and have been fixed to reflect the
 correct identifier.
 
 Additionally Philippe spent 10 hours this week doing a detailed manual
 inspection and review of the 12,461 patched files from the initial patch
 version early this week with:
  - a full scancode scan run, collecting the matched texts, detected
    license ids and scores
  - reviewing anything where there was a license detected (about 500+
    files) to ensure that the applied SPDX license was correct
  - reviewing anything where there was no detection but the patch license
    was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
    SPDX license was correct
 
 This produced a worksheet with 20 files needing minor correction.  This
 worksheet was then exported into 3 different .csv files for the
 different types of files to be modified.
 
 These .csv files were then reviewed by Greg.  Thomas wrote a script to
 parse the csv files and add the proper SPDX tag to the file, in the
 format that the file expected.  This script was further refined by Greg
 based on the output to detect more types of files automatically and to
 distinguish between header and source .c files (which need different
 comment types.)  Finally Greg ran the script using the .csv files to
 generate the patches.
 
 Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
 Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
 Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 -----END PGP SIGNATURE-----

Merge tag 'spdx_identifiers-4.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull initial SPDX identifiers from Greg KH:
 "License cleanup: add SPDX license identifiers to some files

  Many source files in the tree are missing licensing information, which
  makes it harder for compliance tools to determine the correct license.

  By default all files without license information are under the default
  license of the kernel, which is GPL version 2.

  Update the files which contain no license information with the
  'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally
  binding shorthand, which can be used instead of the full boiler plate
  text.

  This patch is based on work done by Thomas Gleixner and Kate Stewart
  and Philippe Ombredanne.

  How this work was done:

  Patches were generated and checked against linux-4.14-rc6 for a subset
  of the use cases:

   - file had no licensing information it it.

   - file was a */uapi/* one with no licensing information in it,

   - file was a */uapi/* one with existing licensing information,

  Further patches will be generated in subsequent months to fix up cases
  where non-standard license headers were used, and references to
  license had to be inferred by heuristics based on keywords.

  The analysis to determine which SPDX License Identifier to be applied
  to a file was done in a spreadsheet of side by side results from of
  the output of two independent scanners (ScanCode & Windriver)
  producing SPDX tag:value files created by Philippe Ombredanne.
  Philippe prepared the base worksheet, and did an initial spot review
  of a few 1000 files.

  The 4.13 kernel was the starting point of the analysis with 60,537
  files assessed. Kate Stewart did a file by file comparison of the
  scanner results in the spreadsheet to determine which SPDX license
  identifier(s) to be applied to the file. She confirmed any
  determination that was not immediately clear with lawyers working with
  the Linux Foundation.

  Criteria used to select files for SPDX license identifier tagging was:

   - Files considered eligible had to be source code files.

   - Make and config files were included as candidates if they contained
     >5 lines of source

   - File already had some variant of a license header in it (even if <5
     lines).

  All documentation files were explicitly excluded.

  The following heuristics were used to determine which SPDX license
  identifiers to apply.

   - when both scanners couldn't find any license traces, file was
     considered to have no license information in it, and the top level
     COPYING file license applied.

     For non */uapi/* files that summary was:

       SPDX license identifier                            # files
       ---------------------------------------------------|-------
       GPL-2.0                                              11139

     and resulted in the first patch in this series.

     If that file was a */uapi/* path one, it was "GPL-2.0 WITH
     Linux-syscall-note" otherwise it was "GPL-2.0". Results of that
     was:

       SPDX license identifier                            # files
       ---------------------------------------------------|-------
       GPL-2.0 WITH Linux-syscall-note                        930

     and resulted in the second patch in this series.

   - if a file had some form of licensing information in it, and was one
     of the */uapi/* ones, it was denoted with the Linux-syscall-note if
     any GPL family license was found in the file or had no licensing in
     it (per prior point). Results summary:

       SPDX license identifier                            # files
       ---------------------------------------------------|------
       GPL-2.0 WITH Linux-syscall-note                       270
       GPL-2.0+ WITH Linux-syscall-note                      169
       ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
       ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
       LGPL-2.1+ WITH Linux-syscall-note                      15
       GPL-1.0+ WITH Linux-syscall-note                       14
       ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
       LGPL-2.0+ WITH Linux-syscall-note                       4
       LGPL-2.1 WITH Linux-syscall-note                        3
       ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
       ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

     and that resulted in the third patch in this series.

   - when the two scanners agreed on the detected license(s), that
     became the concluded license(s).

   - when there was disagreement between the two scanners (one detected
     a license but the other didn't, or they both detected different
     licenses) a manual inspection of the file occurred.

   - In most cases a manual inspection of the information in the file
     resulted in a clear resolution of the license that should apply
     (and which scanner probably needed to revisit its heuristics).

   - When it was not immediately clear, the license identifier was
     confirmed with lawyers working with the Linux Foundation.

   - If there was any question as to the appropriate license identifier,
     the file was flagged for further research and to be revisited later
     in time.

  In total, over 70 hours of logged manual review was done on the
  spreadsheet to determine the SPDX license identifiers to apply to the
  source files by Kate, Philippe, Thomas and, in some cases,
  confirmation by lawyers working with the Linux Foundation.

  Kate also obtained a third independent scan of the 4.13 code base from
  FOSSology, and compared selected files where the other two scanners
  disagreed against that SPDX file, to see if there was new insights.
  The Windriver scanner is based on an older version of FOSSology in
  part, so they are related.

  Thomas did random spot checks in about 500 files from the spreadsheets
  for the uapi headers and agreed with SPDX license identifier in the
  files he inspected. For the non-uapi files Thomas did random spot
  checks in about 15000 files.

  In initial set of patches against 4.14-rc6, 3 files were found to have
  copy/paste license identifier errors, and have been fixed to reflect
  the correct identifier.

  Additionally Philippe spent 10 hours this week doing a detailed manual
  inspection and review of the 12,461 patched files from the initial
  patch version early this week with:

   - a full scancode scan run, collecting the matched texts, detected
     license ids and scores

   - reviewing anything where there was a license detected (about 500+
     files) to ensure that the applied SPDX license was correct

   - reviewing anything where there was no detection but the patch
     license was not GPL-2.0 WITH Linux-syscall-note to ensure that the
     applied SPDX license was correct

  This produced a worksheet with 20 files needing minor correction. This
  worksheet was then exported into 3 different .csv files for the
  different types of files to be modified.

  These .csv files were then reviewed by Greg. Thomas wrote a script to
  parse the csv files and add the proper SPDX tag to the file, in the
  format that the file expected. This script was further refined by Greg
  based on the output to detect more types of files automatically and to
  distinguish between header and source .c files (which need different
  comment types.) Finally Greg ran the script using the .csv files to
  generate the patches.

  Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
  Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
  Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

* tag 'spdx_identifiers-4.14-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  License cleanup: add SPDX license identifier to uapi header files with a license
  License cleanup: add SPDX license identifier to uapi header files with no license
  License cleanup: add SPDX GPL-2.0 license identifier to files with no license
2017-11-02 10:04:46 -07:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Michael Ellerman
2a3d6553cb KVM: PPC: Tie KVM_CAP_PPC_HTM to the user-visible TM feature
Currently we use CPU_FTR_TM to decide if the CPU/kernel can support
TM (Transactional Memory), and if it's true we advertise that to
Qemu (or similar) via KVM_CAP_PPC_HTM.

PPC_FEATURE2_HTM is the user-visible feature bit, which indicates that
the CPU and kernel can support TM. Currently CPU_FTR_TM and
PPC_FEATURE2_HTM always have the same value, either true or false, so
using the former for KVM_CAP_PPC_HTM is correct.

However some Power9 CPUs can operate in a mode where TM is enabled but
TM suspended state is disabled. In this mode CPU_FTR_TM is true, but
PPC_FEATURE2_HTM is false. Instead a different PPC_FEATURE2 bit is
set, to indicate that this different mode of TM is available.

It is not safe to let guests use TM as-is, when the CPU is in this
mode. So to prevent that from happening, use PPC_FEATURE2_HTM to
determine the value of KVM_CAP_PPC_HTM.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-20 11:09:26 +11:00
Paul Mackerras
31a4d4480c Revert "KVM: PPC: Book3S HV: POWER9 does not require secondary thread management"
This reverts commit 94a04bc25a.

In order to run HPT guests on a radix POWER9 host, we will have to run
the host in single-threaded mode, because POWER9 processors do not
currently support running some threads of a core in HPT mode while
others are in radix mode ("mixed mode").

That means that we will need the same mechanisms that are used on
POWER8 to make the secondary threads available to KVM, which were
disabled on POWER9 by commit 94a04bc25a.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-10-19 15:28:04 +11:00
Benjamin Herrenschmidt
ad98dd1a75 KVM: PPC: Book3S HV: Add more barriers in XIVE load/unload code
On POWER9 systems, we push the VCPU context onto the XIVE (eXternal
Interrupt Virtualization Engine) hardware when entering a guest,
and pull the context off the XIVE when exiting the guest.  The push
is done with cache-inhibited stores, and the pull with cache-inhibited
loads.

Testing has revealed that it is possible (though very rare) for
the stores to get reordered with the loads so that we end up with the
guest VCPU context still loaded on the XIVE after we have exited the
guest.  When that happens, it is possible for the same VCPU context
to then get loaded on another CPU, which causes the machine to
checkstop.

To fix this, we add I/O barrier instructions (eieio) before and
after the push and pull operations.  As partial compensation for the
potential slowdown caused by the extra barriers, we remove the eieio
instructions between the two stores in the push operation, and between
the two loads in the pull operation.  (The architecture requires
loads to cache-inhibited, guarded storage to be kept in order, and
requires stores to cache-inhibited, guarded storage likewise to be
kept in order, but allows such loads and stores to be reordered with
respect to each other.)

Reported-by: Carol L Soto <clsoto@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-10-16 08:46:46 +11:00
Alexey Kardashevskiy
8f6a9f0d06 KVM: PPC: Book3S: Protect kvmppc_gpa_to_ua() with SRCU
kvmppc_gpa_to_ua() accesses KVM memory slot array via
srcu_dereference_check() and this produces warnings from RCU like below.

This extends the existing srcu_read_lock/unlock to cover that
kvmppc_gpa_to_ua() as well.

We did not hit this before as this lock is not needed for the realmode
handlers and hash guests would use the realmode path all the time;
however the radix guests are always redirected to the virtual mode
handlers and hence the warning.

[   68.253798] ./include/linux/kvm_host.h:575 suspicious rcu_dereference_check() usage!
[   68.253799]
               other info that might help us debug this:

[   68.253802]
               rcu_scheduler_active = 2, debug_locks = 1
[   68.253804] 1 lock held by qemu-system-ppc/6413:
[   68.253806]  #0:  (&vcpu->mutex){+.+.}, at: [<c00800000e3c22f4>] vcpu_load+0x3c/0xc0 [kvm]
[   68.253826]
               stack backtrace:
[   68.253830] CPU: 92 PID: 6413 Comm: qemu-system-ppc Tainted: G        W       4.14.0-rc3-00553-g432dcba58e9c-dirty #72
[   68.253833] Call Trace:
[   68.253839] [c000000fd3d9f790] [c000000000b7fcc8] dump_stack+0xe8/0x160 (unreliable)
[   68.253845] [c000000fd3d9f7d0] [c0000000001924c0] lockdep_rcu_suspicious+0x110/0x180
[   68.253851] [c000000fd3d9f850] [c0000000000e825c] kvmppc_gpa_to_ua+0x26c/0x2b0
[   68.253858] [c000000fd3d9f8b0] [c00800000e3e1984] kvmppc_h_put_tce+0x12c/0x2a0 [kvm]

Fixes: 121f80ba68 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-10-14 11:35:41 +11:00
Nicholas Piggin
2cde371632 KVM: PPC: Book3S HV: POWER9 more doorbell fixes
- Add another case where msgsync is required.
- Required barrier sequence for global doorbells is msgsync ; lwsync

When msgsnd is used for IPIs to other cores, msgsync must be executed by
the target to order stores performed on the source before its msgsnd
(provided the source executes the appropriate sync).

Fixes: 1704a81cce ("KVM: PPC: Book3S HV: Use msgsnd for IPIs to other cores on POWER9")
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-10-14 11:32:53 +11:00
Greg Kurz
ac64115a66 KVM: PPC: Fix oops when checking KVM_CAP_PPC_HTM
The following program causes a kernel oops:

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/kvm.h>

main()
{
    int fd = open("/dev/kvm", O_RDWR);
    ioctl(fd, KVM_CHECK_EXTENSION, KVM_CAP_PPC_HTM);
}

This happens because when using the global KVM fd with
KVM_CHECK_EXTENSION, kvm_vm_ioctl_check_extension() gets
called with a NULL kvm argument, which gets dereferenced
in is_kvmppc_hv_enabled(). Spotted while reading the code.

Let's use the hv_enabled fallback variable, like everywhere
else in this function.

Fixes: 23528bb21e ("KVM: PPC: Introduce KVM_CAP_PPC_HTM")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-10-14 11:32:53 +11:00
Sam Bobroff
2fb1e94645 KVM: PPC: Book3S: Fix server always zero from kvmppc_xive_get_xive()
In KVM's XICS-on-XIVE emulation, kvmppc_xive_get_xive() returns the
value of state->guest_server as "server". However, this value is not
set by it's counterpart kvmppc_xive_set_xive(). When the guest uses
this interface to migrate interrupts away from a CPU that is going
offline, it sees all interrupts as belonging to CPU 0, so they are
left assigned to (now) offline CPUs.

This patch removes the guest_server field from the state, and returns
act_server in it's place (that is, the CPU actually handling the
interrupt, which may differ from the one requested).

Fixes: 5af5099385 ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Cc: stable@vger.kernel.org
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-10-03 17:58:16 +02:00
Michael Neuling
e001fa78d4 KVM: PPC: Book3S HV: Check for updated HDSISR on P9 HDSI exception
On POWER9 DD2.1 and below, sometimes on a Hypervisor Data Storage
Interrupt (HDSI) the HDSISR is not be updated at all.

To work around this we put a canary value into the HDSISR before
returning to a guest and then check for this canary when we take a
HDSI. If we find the canary on a HDSI, we know the hardware didn't
update the HDSISR. In this case we return to the guest to retake the
HDSI which should correctly update the HDSISR the second time HDSI
entry.

After talking to Paulus we've applied this workaround to all POWER9
CPUs. The workaround of returning to the guest shouldn't ever be
triggered on well behaving CPU. The extra instructions should have
negligible performance impact.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-22 10:45:46 +02:00
Davidlohr Bueso
267ad7bc2d kvm,powerpc: Serialize wq active checks in ops->vcpu_kick
Particularly because kvmppc_fast_vcpu_kick_hv() is a callback,
ensure that we properly serialize wq active checks in order to
avoid potentially missing a wakeup due to racing with the waiter
side.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-15 16:57:13 +02:00
Radim Krčmář
648d453dd4 Merge branch 'kvm-ppc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
Bug fixes for stable.
2017-09-14 17:21:10 +02:00
Paul Mackerras
67f8a8c115 KVM: PPC: Book3S HV: Fix bug causing host SLB to be restored incorrectly
Aneesh Kumar reported seeing host crashes when running recent kernels
on POWER8.  The symptom was an oops like this:

Unable to handle kernel paging request for data at address 0xf00000000786c620
Faulting instruction address: 0xc00000000030e1e4
Oops: Kernel access of bad area, sig: 11 [#1]
LE SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in: powernv_op_panel
CPU: 24 PID: 6663 Comm: qemu-system-ppc Tainted: G        W 4.13.0-rc7-43932-gfc36c59 #2
task: c000000fdeadfe80 task.stack: c000000fdeb68000
NIP:  c00000000030e1e4 LR: c00000000030de6c CTR: c000000000103620
REGS: c000000fdeb6b450 TRAP: 0300   Tainted: G        W        (4.13.0-rc7-43932-gfc36c59)
MSR:  9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR: 24044428  XER: 20000000
CFAR: c00000000030e134 DAR: f00000000786c620 DSISR: 40000000 SOFTE: 0
GPR00: 0000000000000000 c000000fdeb6b6d0 c0000000010bd000 000000000000e1b0
GPR04: c00000000115e168 c000001fffa6e4b0 c00000000115d000 c000001e1b180386
GPR08: f000000000000000 c000000f9a8913e0 f00000000786c600 00007fff587d0000
GPR12: c000000fdeb68000 c00000000fb0f000 0000000000000001 00007fff587cffff
GPR16: 0000000000000000 c000000000000000 00000000003fffff c000000fdebfe1f8
GPR20: 0000000000000004 c000000fdeb6b8a8 0000000000000001 0008000000000040
GPR24: 07000000000000c0 00007fff587cffff c000000fdec20bf8 00007fff587d0000
GPR28: c000000fdeca9ac0 00007fff587d0000 00007fff587c0000 00007fff587d0000
NIP [c00000000030e1e4] __get_user_pages_fast+0x434/0x1070
LR [c00000000030de6c] __get_user_pages_fast+0xbc/0x1070
Call Trace:
[c000000fdeb6b6d0] [c00000000139dab8] lock_classes+0x0/0x35fe50 (unreliable)
[c000000fdeb6b7e0] [c00000000030ef38] get_user_pages_fast+0xf8/0x120
[c000000fdeb6b830] [c000000000112318] kvmppc_book3s_hv_page_fault+0x308/0xf30
[c000000fdeb6b960] [c00000000010e10c] kvmppc_vcpu_run_hv+0xfdc/0x1f00
[c000000fdeb6bb20] [c0000000000e915c] kvmppc_vcpu_run+0x2c/0x40
[c000000fdeb6bb40] [c0000000000e5650] kvm_arch_vcpu_ioctl_run+0x110/0x300
[c000000fdeb6bbe0] [c0000000000d6468] kvm_vcpu_ioctl+0x528/0x900
[c000000fdeb6bd40] [c0000000003bc04c] do_vfs_ioctl+0xcc/0x950
[c000000fdeb6bde0] [c0000000003bc930] SyS_ioctl+0x60/0x100
[c000000fdeb6be30] [c00000000000b96c] system_call+0x58/0x6c
Instruction dump:
7ca81a14 2fa50000 41de0010 7cc8182a 68c60002 78c6ffe2 0b060000 3cc2000a
794a3664 390610d8 e9080000 7d485214 <e90a0020> 7d435378 790507e1 408202f0
---[ end trace fad4a342d0414aa2 ]---

It turns out that what has happened is that the SLB entry for the
vmmemap region hasn't been reloaded on exit from a guest, and it has
the wrong page size.  Then, when the host next accesses the vmemmap
region, it gets a page fault.

Commit a25bd72bad ("powerpc/mm/radix: Workaround prefetch issue with
KVM", 2017-07-24) modified the guest exit code so that it now only clears
out the SLB for hash guest.  The code tests the radix flag and puts the
result in a non-volatile CR field, CR2, and later branches based on CR2.

Unfortunately, the kvmppc_save_tm function, which gets called between
those two points, modifies all the user-visible registers in the case
where the guest was in transactional or suspended state, except for a
few which it restores (namely r1, r2, r9 and r13).  Thus the hash/radix indication in CR2 gets corrupted.

This fixes the problem by re-doing the comparison just before the
result is needed.  For good measure, this also adds comments next to
the call sites of kvmppc_save_tm and kvmppc_restore_tm pointing out
that non-volatile register state will be lost.

Cc: stable@vger.kernel.org # v4.13
Fixes: a25bd72bad ("powerpc/mm/radix: Workaround prefetch issue with KVM")
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-09-12 16:02:46 +10:00
Paul Mackerras
cf5f6f3125 KVM: PPC: Book3S HV: Hold kvm->lock around call to kvmppc_update_lpcr
Commit 468808bd35 ("KVM: PPC: Book3S HV: Set process table for HPT
guests on POWER9", 2017-01-30) added a call to kvmppc_update_lpcr()
which doesn't hold the kvm->lock mutex around the call, as required.
This adds the lock/unlock pair, and for good measure, includes
the kvmppc_setup_partition_table() call in the locked region, since
it is altering global state of the VM.

This error appears not to have any fatal consequences for the host;
the consequences would be that the VCPUs could end up running with
different LPCR values, or an update to the LPCR value by userspace
using the one_reg interface could get overwritten, or the update
done by kvmhv_configure_mmu() could get overwritten.

Cc: stable@vger.kernel.org # v4.10+
Fixes: 468808bd35 ("KVM: PPC: Book3S HV: Set process table for HPT guests on POWER9")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-09-12 16:02:27 +10:00
Benjamin Herrenschmidt
d222af0723 KVM: PPC: Book3S HV: Don't access XIVE PIPR register using byte accesses
The XIVE interrupt controller on POWER9 machines doesn't support byte
accesses to any register in the thread management area other than the
CPPR (current processor priority register).  In particular, when
reading the PIPR (pending interrupt priority register), we need to
do a 32-bit or 64-bit load.

Cc: stable@vger.kernel.org # v4.13
Fixes: 2c4fb78f78 ("KVM: PPC: Book3S HV: Workaround POWER9 DD1.0 bug causing IPB bit loss")
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-09-12 16:02:07 +10:00
Linus Torvalds
0756b7fbb6 First batch of KVM changes for 4.14
Common:
  - improve heuristic for boosting preempted spinlocks by ignoring VCPUs
    in user mode
 
 ARM:
  - fix for decoding external abort types from guests
 
  - added support for migrating the active priority of interrupts when
    running a GICv2 guest on a GICv3 host
 
  - minor cleanup
 
 PPC:
  - expose storage keys to userspace
 
  - merge powerpc/topic/ppc-kvm branch that contains
    find_linux_pte_or_hugepte and POWER9 thread management cleanup
 
  - merge kvm-ppc-fixes with a fix that missed 4.13 because of vacations
 
  - fixes
 
 s390:
  - merge of topic branch tlb-flushing from the s390 tree to get the
    no-dat base features
 
  - merge of kvm/master to avoid conflicts with additional sthyi fixes
 
  - wire up the no-dat enhancements in KVM
 
  - multiple epoch facility (z14 feature)
 
  - Configuration z/Architecture Mode
 
  - more sthyi fixes
 
  - gdb server range checking fix
 
  - small code cleanups
 
 x86:
  - emulate Hyper-V TSC frequency MSRs
 
  - add nested INVPCID
 
  - emulate EPTP switching VMFUNC
 
  - support Virtual GIF
 
  - support 5 level page tables
 
  - speedup nested VM exits by packing byte operations
 
  - speedup MMIO by using hardware provided physical address
 
  - a lot of fixes and cleanups, especially nested
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Merge tag 'kvm-4.14-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Radim Krčmář:
 "First batch of KVM changes for 4.14

  Common:
   - improve heuristic for boosting preempted spinlocks by ignoring
     VCPUs in user mode

  ARM:
   - fix for decoding external abort types from guests

   - added support for migrating the active priority of interrupts when
     running a GICv2 guest on a GICv3 host

   - minor cleanup

  PPC:
   - expose storage keys to userspace

   - merge kvm-ppc-fixes with a fix that missed 4.13 because of
     vacations

   - fixes

  s390:
   - merge of kvm/master to avoid conflicts with additional sthyi fixes

   - wire up the no-dat enhancements in KVM

   - multiple epoch facility (z14 feature)

   - Configuration z/Architecture Mode

   - more sthyi fixes

   - gdb server range checking fix

   - small code cleanups

  x86:
   - emulate Hyper-V TSC frequency MSRs

   - add nested INVPCID

   - emulate EPTP switching VMFUNC

   - support Virtual GIF

   - support 5 level page tables

   - speedup nested VM exits by packing byte operations

   - speedup MMIO by using hardware provided physical address

   - a lot of fixes and cleanups, especially nested"

* tag 'kvm-4.14-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (67 commits)
  KVM: arm/arm64: Support uaccess of GICC_APRn
  KVM: arm/arm64: Extract GICv3 max APRn index calculation
  KVM: arm/arm64: vITS: Drop its_ite->lpi field
  KVM: arm/arm64: vgic: constify seq_operations and file_operations
  KVM: arm/arm64: Fix guest external abort matching
  KVM: PPC: Book3S HV: Fix memory leak in kvm_vm_ioctl_get_htab_fd
  KVM: s390: vsie: cleanup mcck reinjection
  KVM: s390: use WARN_ON_ONCE only for checking
  KVM: s390: guestdbg: fix range check
  KVM: PPC: Book3S HV: Report storage key support to userspace
  KVM: PPC: Book3S HV: Fix case where HDEC is treated as 32-bit on POWER9
  KVM: PPC: Book3S HV: Fix invalid use of register expression
  KVM: PPC: Book3S HV: Fix H_REGISTER_VPA VPA size validation
  KVM: PPC: Book3S HV: Fix setting of storage key in H_ENTER
  KVM: PPC: e500mc: Fix a NULL dereference
  KVM: PPC: e500: Fix some NULL dereferences on error
  KVM: PPC: Book3S HV: Protect updates to spapr_tce_tables list
  KVM: s390: we are always in czam mode
  KVM: s390: expose no-DAT to guest and migration support
  KVM: s390: sthyi: remove invalid guest write access
  ...
2017-09-08 15:18:36 -07:00
Radim Krčmář
5f54c8b2d4 Merge branch 'kvm-ppc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
This fix was intended for 4.13, but didn't get in because both
maintainers were on vacation.

Paul Mackerras:
 "It adds mutual exclusion between list_add_rcu and list_del_rcu calls
  on the kvm->arch.spapr_tce_tables list.  Without this, userspace could
  potentially trigger corruption of the list and cause a host crash or
  worse."
2017-09-08 14:40:43 +02:00
Linus Torvalds
bac65d9d87 powerpc updates for 4.14
Nothing really major this release, despite quite a lot of activity. Just lots of
 things all over the place.
 
 Some things of note include:
 
  - Access via perf to a new type of PMU (IMC) on Power9, which can count both
    core events as well as nest unit events (Memory controller etc).
 
  - Optimisations to the radix MMU TLB flushing, mostly to avoid unnecessary Page
    Walk Cache (PWC) flushes when the structure of the tree is not changing.
 
  - Reworks/cleanups of do_page_fault() to modernise it and bring it closer to
    other architectures where possible.
 
  - Rework of our page table walking so that THP updates only need to send IPIs
    to CPUs where the affected mm has run, rather than all CPUs.
 
  - The size of our vmalloc area is increased to 56T on 64-bit hash MMU systems.
    This avoids problems with the percpu allocator on systems with very sparse
    NUMA layouts.
 
  - STRICT_KERNEL_RWX support on PPC32.
 
  - A new sched domain topology for Power9, to capture the fact that pairs of
    cores may share an L2 cache.
 
  - Power9 support for VAS, which is a new mechanism for accessing coprocessors,
    and initial support for using it with the NX compression accelerator.
 
  - Major work on the instruction emulation support, adding support for many new
    instructions, and reworking it so it can be used to implement the emulation
    needed to fixup alignment faults.
 
  - Support for guests under PowerVM to use the Power9 XIVE interrupt controller.
 
 And probably that many things again that are almost as interesting, but I had to
 keep the list short. Plus the usual fixes and cleanups as always.
 
 Thanks to:
   Alexey Kardashevskiy, Alistair Popple, Andreas Schwab, Aneesh Kumar K.V, Anju
   T Sudhakar, Arvind Yadav, Balbir Singh, Benjamin Herrenschmidt, Bhumika Goyal,
   Breno Leitao, Bryant G. Ly, Christophe Leroy, Cédric Le Goater, Dan Carpenter,
   Dou Liyang, Frederic Barrat, Gautham R. Shenoy, Geliang Tang, Geoff Levand,
   Hannes Reinecke, Haren Myneni, Ivan Mikhaylov, John Allen, Julia Lawall, LABBE
   Corentin, Laurentiu Tudor, Madhavan Srinivasan, Markus Elfring, Masahiro
   Yamada, Matt Brown, Michael Neuling, Murilo Opsfelder Araujo, Nathan Fontenot,
   Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Rashmica
   Gupta, Rob Herring, Rui Teng, Sam Bobroff, Santosh Sivaraj, Scott Wood,
   Shilpasri G Bhat, Sukadev Bhattiprolu, Suraj Jitindar Singh, Tobin C. Harding,
   Victor Aoqui.
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Merge tag 'powerpc-4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Nothing really major this release, despite quite a lot of activity.
  Just lots of things all over the place.

  Some things of note include:

   - Access via perf to a new type of PMU (IMC) on Power9, which can
     count both core events as well as nest unit events (Memory
     controller etc).

   - Optimisations to the radix MMU TLB flushing, mostly to avoid
     unnecessary Page Walk Cache (PWC) flushes when the structure of the
     tree is not changing.

   - Reworks/cleanups of do_page_fault() to modernise it and bring it
     closer to other architectures where possible.

   - Rework of our page table walking so that THP updates only need to
     send IPIs to CPUs where the affected mm has run, rather than all
     CPUs.

   - The size of our vmalloc area is increased to 56T on 64-bit hash MMU
     systems. This avoids problems with the percpu allocator on systems
     with very sparse NUMA layouts.

   - STRICT_KERNEL_RWX support on PPC32.

   - A new sched domain topology for Power9, to capture the fact that
     pairs of cores may share an L2 cache.

   - Power9 support for VAS, which is a new mechanism for accessing
     coprocessors, and initial support for using it with the NX
     compression accelerator.

   - Major work on the instruction emulation support, adding support for
     many new instructions, and reworking it so it can be used to
     implement the emulation needed to fixup alignment faults.

   - Support for guests under PowerVM to use the Power9 XIVE interrupt
     controller.

  And probably that many things again that are almost as interesting,
  but I had to keep the list short. Plus the usual fixes and cleanups as
  always.

  Thanks to: Alexey Kardashevskiy, Alistair Popple, Andreas Schwab,
  Aneesh Kumar K.V, Anju T Sudhakar, Arvind Yadav, Balbir Singh,
  Benjamin Herrenschmidt, Bhumika Goyal, Breno Leitao, Bryant G. Ly,
  Christophe Leroy, Cédric Le Goater, Dan Carpenter, Dou Liyang,
  Frederic Barrat, Gautham R. Shenoy, Geliang Tang, Geoff Levand, Hannes
  Reinecke, Haren Myneni, Ivan Mikhaylov, John Allen, Julia Lawall,
  LABBE Corentin, Laurentiu Tudor, Madhavan Srinivasan, Markus Elfring,
  Masahiro Yamada, Matt Brown, Michael Neuling, Murilo Opsfelder Araujo,
  Nathan Fontenot, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran,
  Paul Mackerras, Rashmica Gupta, Rob Herring, Rui Teng, Sam Bobroff,
  Santosh Sivaraj, Scott Wood, Shilpasri G Bhat, Sukadev Bhattiprolu,
  Suraj Jitindar Singh, Tobin C. Harding, Victor Aoqui"

* tag 'powerpc-4.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (321 commits)
  powerpc/xive: Fix section __init warning
  powerpc: Fix kernel crash in emulation of vector loads and stores
  powerpc/xive: improve debugging macros
  powerpc/xive: add XIVE Exploitation Mode to CAS
  powerpc/xive: introduce H_INT_ESB hcall
  powerpc/xive: add the HW IRQ number under xive_irq_data
  powerpc/xive: introduce xive_esb_write()
  powerpc/xive: rename xive_poke_esb() in xive_esb_read()
  powerpc/xive: guest exploitation of the XIVE interrupt controller
  powerpc/xive: introduce a common routine xive_queue_page_alloc()
  powerpc/sstep: Avoid used uninitialized error
  axonram: Return directly after a failed kzalloc() in axon_ram_probe()
  axonram: Improve a size determination in axon_ram_probe()
  axonram: Delete an error message for a failed memory allocation in axon_ram_probe()
  powerpc/powernv/npu: Move tlb flush before launching ATSD
  powerpc/macintosh: constify wf_sensor_ops structures
  powerpc/iommu: Use permission-specific DEVICE_ATTR variants
  powerpc/eeh: Delete an error out of memory message at init time
  powerpc/mm: Use seq_putc() in two functions
  macintosh: Convert to using %pOF instead of full_name
  ...
2017-09-07 10:15:40 -07:00
nixiaoming
43f6b0cfb2 KVM: PPC: Book3S HV: Fix memory leak in kvm_vm_ioctl_get_htab_fd
We do ctx = kzalloc(sizeof(*ctx), GFP_KERNEL) and then later on call
anon_inode_getfd(), but if that fails we don't free ctx, so that
memory gets leaked.  To fix it, this adds kfree(ctx) in the failure
path.

Signed-off-by: nixiaoming <nixiaoming@huawei.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-09-01 10:17:58 +10:00
Paul Mackerras
4dafecde44 Merge remote-tracking branch 'remotes/powerpc/topic/ppc-kvm' into kvm-ppc-next
This merges in the 'ppc-kvm' topic branch from the powerpc tree in
order to bring in some fixes which touch both powerpc and KVM code.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-31 12:37:03 +10:00
Paul Mackerras
e3bfed1df3 KVM: PPC: Book3S HV: Report storage key support to userspace
This adds information about storage keys to the struct returned by
the KVM_PPC_GET_SMMU_INFO ioctl.  The new fields replace a pad field,
which was zeroed by previous kernel versions.  Thus userspace that
knows about the new fields will see zeroes when running on an older
kernel, indicating that storage keys are not supported.  The size of
the structure has not changed.

The number of keys is hard-coded for the CPUs supported by HV KVM,
which is just POWER7, POWER8 and POWER9.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-31 12:36:44 +10:00
Paul Mackerras
a4faf2e77a KVM: PPC: Book3S HV: Fix case where HDEC is treated as 32-bit on POWER9
Commit 2f2724630f ("KVM: PPC: Book3S HV: Cope with host using large
decrementer mode", 2017-05-22) added code to treat the hypervisor
decrementer (HDEC) as a 64-bit value on POWER9 rather than 32-bit.
Unfortunately, that commit missed one place where HDEC is treated
as a 32-bit value.  This fixes it.

This bug should not have any user-visible consequences that I can
think of, beyond an occasional unnecessary exit to the host kernel.
If the hypervisor decrementer has gone negative, then the bottom
32 bits will be negative for about 4 seconds after that, so as
long as we get out of the guest within those 4 seconds we won't
conclude that the HDEC interrupt is spurious.

Reported-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Fixes: 2f2724630f ("KVM: PPC: Book3S HV: Cope with host using large decrementer mode")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-31 12:36:44 +10:00
Andreas Schwab
0bfa33c7f7 KVM: PPC: Book3S HV: Fix invalid use of register expression
binutils >= 2.26 now warns about misuse of register expressions in
assembler operands that are actually literals. In this instance r0 is
being used where a literal 0 should be used.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
[mpe: Split into separate KVM patch, tweak change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-31 12:36:44 +10:00
Nicholas Piggin
eaac112eac KVM: PPC: Book3S HV: Fix H_REGISTER_VPA VPA size validation
KVM currently validates the size of the VPA registered by the client
against sizeof(struct lppaca), however we align (and therefore size)
that struct to 1kB to avoid crossing a 4kB boundary in the client.

PAPR calls for sizes >= 640 bytes to be accepted. Hard code this with
a comment.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-31 12:36:44 +10:00
Ram Pai
d182b8fd60 KVM: PPC: Book3S HV: Fix setting of storage key in H_ENTER
In handling a H_ENTER hypercall, the code in kvmppc_do_h_enter
clobbers the high-order two bits of the storage key, which is stored
in a split field in the second doubleword of the HPTE.  Any storage
key number above 7 hence fails to operate correctly.

This makes sure we preserve all the bits of the storage key.

Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-31 12:36:44 +10:00
Dan Carpenter
50a1a25987 KVM: PPC: e500mc: Fix a NULL dereference
We should set "err = -ENOMEM;", otherwise it means we're returning
ERR_PTR(0) which is NULL.  It results in a NULL pointer dereference in
the caller.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-31 12:36:44 +10:00
Dan Carpenter
73e77c0982 KVM: PPC: e500: Fix some NULL dereferences on error
There are some error paths in kvmppc_core_vcpu_create_e500() where we
forget to set the error code.  It means that we return ERR_PTR(0) which
is NULL and it results in a NULL pointer dereference in the caller.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-31 12:36:44 +10:00
Paul Mackerras
edd03602d9 KVM: PPC: Book3S HV: Protect updates to spapr_tce_tables list
Al Viro pointed out that while one thread of a process is executing
in kvm_vm_ioctl_create_spapr_tce(), another thread could guess the
file descriptor returned by anon_inode_getfd() and close() it before
the first thread has added it to the kvm->arch.spapr_tce_tables list.
That highlights a more general problem: there is no mutual exclusion
between writers to the spapr_tce_tables list, leading to the
possibility of the list becoming corrupted, which could cause a
host kernel crash.

To fix the mutual exclusion problem, we add a mutex_lock/unlock
pair around the list_del_rce in kvm_spapr_tce_release().  Also,
this moves the call to anon_inode_getfd() inside the region
protected by the kvm->lock mutex, after we have done the check for
a duplicate LIOBN.  This means that if another thread does guess the
file descriptor and closes it, its call to kvm_spapr_tce_release()
will not do any harm because it will have to wait until the first
thread has released kvm->lock.  With this, there are no failure
points in kvm_vm_ioctl_create_spapr_tce() after the call to
anon_inode_getfd().

The other things that the second thread could do with the guessed
file descriptor are to mmap it or to pass it as a parameter to a
KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE ioctl on a KVM device fd.  An mmap
call won't cause any harm because kvm_spapr_tce_mmap() and
kvm_spapr_tce_fault() don't access the spapr_tce_tables list or
the kvmppc_spapr_tce_table.list field, and the fields that they do use
have been properly initialized by the time of the anon_inode_getfd()
call.

The KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE ioctl calls
kvm_spapr_tce_attach_iommu_group(), which scans the spapr_tce_tables
list looking for the kvmppc_spapr_tce_table struct corresponding to
the fd given as the parameter.  Either it will find the new entry
or it won't; if it doesn't, it just returns an error, and if it
does, it will function normally.  So, in each case there is no
harmful effect.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-30 14:59:31 +10:00
Michael Ellerman
82b7fcc005 Merge branch 'topic/ppc-kvm' into next
Merge Nicks commit to rework the KVM thread management, shared with the
KVM tree via the ppc-kvm topic branch.
2017-08-29 21:26:30 +10:00
Nicholas Piggin
94a04bc25a KVM: PPC: Book3S HV: POWER9 does not require secondary thread management
POWER9 CPUs have independent MMU contexts per thread, so KVM does not
need to quiesce secondary threads, so the hwthread_req/hwthread_state
protocol does not have to be used. So patch it away on POWER9, and patch
away the branch from the Linux idle wakeup to kvm_start_guest that is
never used.

Add a warning and error out of kvmppc_grab_hwthread in case it is ever
called on POWER9.

This avoids a hwsync in the idle wakeup path on POWER9.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
[mpe: Use WARN(...) instead of WARN_ON()/pr_err(...)]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-29 14:48:59 +10:00
Paul Mackerras
47c5310a8d KVM: PPC: Book3S: Fix race and leak in kvm_vm_ioctl_create_spapr_tce()
Nixiaoming pointed out that there is a memory leak in
kvm_vm_ioctl_create_spapr_tce() if the call to anon_inode_getfd()
fails; the memory allocated for the kvmppc_spapr_tce_table struct
is not freed, and nor are the pages allocated for the iommu
tables.  In addition, we have already incremented the process's
count of locked memory pages, and this doesn't get restored on
error.

David Hildenbrand pointed out that there is a race in that the
function checks early on that there is not already an entry in the
stt->iommu_tables list with the same LIOBN, but an entry with the
same LIOBN could get added between then and when the new entry is
added to the list.

This fixes all three problems.  To simplify things, we now call
anon_inode_getfd() before placing the new entry in the list.  The
check for an existing entry is done while holding the kvm->lock
mutex, immediately before adding the new entry to the list.
Finally, on failure we now call kvmppc_account_memlimit to
decrement the process's count of locked memory pages.

Reported-by: Nixiaoming <nixiaoming@huawei.com>
Reported-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-25 11:08:57 +02:00
Benjamin Herrenschmidt
bb9b52bd51 KVM: PPC: Book3S HV: Add missing barriers to XIVE code and document them
This adds missing memory barriers to order updates/tests of
the virtual CPPR and MFRR, thus fixing a lost IPI problem.

While at it also document all barriers in this file.

This fixes a bug causing guest IPIs to occasionally get lost.  The
symptom then is hangs or stalls in the guest.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-24 20:02:01 +10:00
Benjamin Herrenschmidt
2c4fb78f78 KVM: PPC: Book3S HV: Workaround POWER9 DD1.0 bug causing IPB bit loss
This adds a workaround for a bug in POWER9 DD1 chips where changing
the CPPR (Current Processor Priority Register) can cause bits in the
IPB (Interrupt Pending Buffer) to get lost.  Thankfully it only
happens when manually manipulating CPPR which is quite rare.  When it
does happen it can cause interrupts to be delayed or lost.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-24 20:01:39 +10:00
Nicholas Piggin
bd0fdb191c KVM: PPC: Book3S HV: Use msgsync with hypervisor doorbells on POWER9
When msgsnd is used for IPIs to other cores, msgsync must be executed by
the target to order stores performed on the source before its msgsnd
(provided the source executes the appropriate sync).

Fixes: 1704a81cce ("KVM: PPC: Book3S HV: Use msgsnd for IPIs to other cores on POWER9")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-08-24 20:01:39 +10:00
Michael Ellerman
15c659ff9d Merge branch 'fixes' into next
There's a non-trivial dependency between some commits we want to put in
next and the KVM prefetch work around that went into fixes. So merge
fixes into next.
2017-08-23 22:20:10 +10:00
Michael Ellerman
8434f0892e Merge branch 'topic/ppc-kvm' into next
Bring in the commit to rename find_linux_pte_or_hugepte() which touches
arch and KVM code, and might need to be merged with the kvmppc tree to
avoid conflicts.
2017-08-17 23:14:17 +10:00
Aneesh Kumar K.V
94171b19c3 powerpc/mm: Rename find_linux_pte_or_hugepte()
Add newer helpers to make the function usage simpler. It is always
recommended to use find_current_mm_pte() for walking the page table.
If we cannot use find_current_mm_pte(), it should be documented why
the said usage of __find_linux_pte() is safe against a parallel THP
split.

For now we have KVM code using __find_linux_pte(). This is because kvm
code ends up calling __find_linux_pte() in real mode with MSR_EE=0 but
with PACA soft_enabled = 1. We may want to fix that later and make
sure we keep the MSR_EE and PACA soft_enabled in sync. When we do that
we can switch kvm to use find_linux_pte().

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-17 23:13:46 +10:00
Longpeng(Mike)
199b5763d3 KVM: add spinlock optimization framework
If a vcpu exits due to request a user mode spinlock, then
the spinlock-holder may be preempted in user mode or kernel mode.
(Note that not all architectures trap spin loops in user mode,
only AMD x86 and ARM/ARM64 currently do).

But if a vcpu exits in kernel mode, then the holder must be
preempted in kernel mode, so we should choose a vcpu in kernel mode
as a more likely candidate for the lock holder.

This introduces kvm_arch_vcpu_in_kernel() to decide whether the
vcpu is in kernel-mode when it's preempted.  kvm_vcpu_on_spin's
new argument says the same of the spinning VCPU.

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-08 10:57:43 +02:00
Benjamin Herrenschmidt
870cfe77a9 powerpc/mm: Update definitions of DSISR bits
This updates the definitions for the various DSISR bits to
match both some historical stuff and to match new bits on
POWER9.

In addition, we define some masks corresponding to the "bad"
faults on Book3S, and some masks corresponding to the bits
that match between DSISR and SRR1 for a DSI and an ISI.

This comes with a small code update to change the definition
of DSISR_PGDIRFAULT which becomes DSISR_PRTABLE_FAULT to
match architecture 3.0B

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-03 16:06:43 +10:00
Michael Ellerman
bb272221e9 Linux v4.13-rc1
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Merge tag 'v4.13-rc1' into fixes

The fixes branch is based off a random pre-rc1 commit, because we had
some fixes that needed to go in before rc1 was released.

However we now need to fix some code that went in after that point, but
before rc1, so merge rc1 to get that code into fixes so we can fix it!
2017-07-31 20:20:29 +10:00
Linus Torvalds
8155469341 s390: SRCU fix.
PPC: host crash fixes.
 x86: bugfixes, including making nested posted interrupts really work.
 Generic: tweaks to kvm_stat and to uevents
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM fixes from Paolo Bonzini:
 "s390:
   - SRCU fix

  PPC:
   - host crash fixes

  x86:
   - bugfixes, including making nested posted interrupts really work

  Generic:
   - tweaks to kvm_stat and to uevents"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: LAPIC: Fix reentrancy issues with preempt notifiers
  tools/kvm_stat: add '-f help' to get the available event list
  tools/kvm_stat: use variables instead of hard paths in help output
  KVM: nVMX: Fix loss of L2's NMI blocking state
  KVM: nVMX: Fix posted intr delivery when vcpu is in guest mode
  x86: irq: Define a global vector for nested posted interrupts
  KVM: x86: do mask out upper bits of PAE CR3
  KVM: make pid available for uevents without debugfs
  KVM: s390: take srcu lock when getting/setting storage keys
  KVM: VMX: remove unused field
  KVM: PPC: Book3S HV: Fix host crash on changing HPT size
  KVM: PPC: Book3S HV: Enable TM before accessing TM registers
2017-07-28 13:36:56 -07:00
Linus Torvalds
080012bad6 powerpc fixes for 4.13 #4
The highlight is Ben's patch to work around a host killing bug when running KVM
 guests with the Radix MMU on Power9. See the long change log of that commit for
 more detail.
 
 And then three fairly minor fixes:
  - Fix of_node_put() underflow during reconfig remove, using old DLPAR tools.
  - Fix recently introduced ld version check with 64-bit LE-only toolchain.
  - Free the subpage_prot_table correctly, avoiding a memory leak.
 
 Thanks to:
   Aneesh Kumar K.V, Benjamin Herrenschmidt, Laurent Vivier.
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Merge tag 'powerpc-4.13-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "The highlight is Ben's patch to work around a host killing bug when
  running KVM guests with the Radix MMU on Power9. See the long change
  log of that commit for more detail.

  And then three fairly minor fixes:

   - fix of_node_put() underflow during reconfig remove, using old DLPAR
     tools.

   - fix recently introduced ld version check with 64-bit LE-only
     toolchain.

   - free the subpage_prot_table correctly, avoiding a memory leak.

  Thanks to: Aneesh Kumar K.V, Benjamin Herrenschmidt, Laurent Vivier"

* tag 'powerpc-4.13-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/mm/hash: Free the subpage_prot_table correctly
  powerpc/Makefile: Fix ld version check with 64-bit LE-only toolchain
  powerpc/pseries: Fix of_node_put() underflow during reconfig remove
  powerpc/mm/radix: Workaround prefetch issue with KVM
2017-07-28 13:25:15 -07:00
Benjamin Herrenschmidt
a25bd72bad powerpc/mm/radix: Workaround prefetch issue with KVM
There's a somewhat architectural issue with Radix MMU and KVM.

When coming out of a guest with AIL (Alternate Interrupt Location, ie,
MMU enabled), we start executing hypervisor code with the PID register
still containing whatever the guest has been using.

The problem is that the CPU can (and will) then start prefetching or
speculatively load from whatever host context has that same PID (if
any), thus bringing translations for that context into the TLB, which
Linux doesn't know about.

This can cause stale translations and subsequent crashes.

Fixing this in a way that is neither racy nor a huge performance
impact is difficult. We could just make the host invalidations always
use broadcast forms but that would hurt single threaded programs for
example.

We chose to fix it instead by partitioning the PID space between guest
and host. This is possible because today Linux only use 19 out of the
20 bits of PID space, so existing guests will work if we make the host
use the top half of the 20 bits space.

We additionally add support for a property to indicate to Linux the
size of the PID register which will be useful if we eventually have
processors with a larger PID space available.

There is still an issue with malicious guests purposefully setting the
PID register to a value in the hosts PID range. Hopefully future HW
can prevent that, but in the meantime, we handle it with a pair of
kludges:

 - On the way out of a guest, before we clear the current VCPU in the
   PACA, we check the PID and if it's outside of the permitted range
   we flush the TLB for that PID.

 - When context switching, if the mm is "new" on that CPU (the
   corresponding bit was set for the first time in the mm cpumask), we
   check if any sibling thread is in KVM (has a non-NULL VCPU pointer
   in the PACA). If that is the case, we also flush the PID for that
   CPU (core).

This second part is needed to handle the case where a process is
migrated (or starts a new pthread) on a sibling thread of the CPU
coming out of KVM, as there's a window where stale translations can
exist before we detect it and flush them out.

A future optimization could be added by keeping track of whether the
PID has ever been used and avoid doing that for completely fresh PIDs.
We could similarily mark PIDs that have been the subject of a global
invalidation as "fresh". But for now this will do.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Rework the asm to build with CONFIG_PPC_RADIX_MMU=n, drop
      unneeded include of kvm_book3s_asm.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-26 16:41:52 +10:00
Paul Mackerras
ef42719814 KVM: PPC: Book3S HV: Fix host crash on changing HPT size
Commit f98a8bf9ee ("KVM: PPC: Book3S HV: Allow KVM_PPC_ALLOCATE_HTAB
ioctl() to change HPT size", 2016-12-20) changed the behaviour of
the KVM_PPC_ALLOCATE_HTAB ioctl so that it now allocates a new HPT
and new revmap array if there was a previously-allocated HPT of a
different size from the size being requested.  In this case, we need
to reset the rmap arrays of the memslots, because the rmap arrays
will contain references to HPTEs which are no longer valid.  Worse,
these references are also references to slots in the new revmap
array (which parallels the HPT), and the new revmap array contains
random contents, since it doesn't get zeroed on allocation.

The effect of having these stale references to slots in the revmap
array that contain random contents is that subsequent calls to
functions such as kvmppc_add_revmap_chain will crash because they
will interpret the non-zero contents of the revmap array as HPTE
indexes and thus index outside of the revmap array.  This leads to
host crashes such as the following.

[ 7072.862122] Unable to handle kernel paging request for data at address 0xd000000c250c00f8
[ 7072.862218] Faulting instruction address: 0xc0000000000e1c78
[ 7072.862233] Oops: Kernel access of bad area, sig: 11 [#1]
[ 7072.862286] SMP NR_CPUS=1024
[ 7072.862286] NUMA
[ 7072.862325] PowerNV
[ 7072.862378] Modules linked in: kvm_hv vhost_net vhost tap xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_mangle ip6table_security ip6table_raw iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw ebtable_filter ebtables ip6table_filter ip6_tables rpcrdma ib_isert iscsi_target_mod ib_iser libiscsi scsi_transport_iscsi ib_srpt target_core_mod ib_srp scsi_transport_srp ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm iw_cxgb3 mlx5_ib ib_core ses enclosure scsi_transport_sas ipmi_powernv ipmi_devintf ipmi_msghandler powernv_op_panel i2c_opal nfsd auth_rpcgss oid_registry
[ 7072.863085]  nfs_acl lockd grace sunrpc kvm_pr kvm xfs libcrc32c scsi_dh_alua dm_service_time radeon lpfc nvme_fc nvme_fabrics nvme_core scsi_transport_fc i2c_algo_bit tg3 drm_kms_helper ptp pps_core syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm dm_multipath i2c_core cxgb3 mlx5_core mdio [last unloaded: kvm_hv]
[ 7072.863381] CPU: 72 PID: 56929 Comm: qemu-system-ppc Not tainted 4.12.0-kvm+ #59
[ 7072.863457] task: c000000fe29e7600 task.stack: c000001e3ffec000
[ 7072.863520] NIP: c0000000000e1c78 LR: c0000000000e2e3c CTR: c0000000000e25f0
[ 7072.863596] REGS: c000001e3ffef560 TRAP: 0300   Not tainted  (4.12.0-kvm+)
[ 7072.863658] MSR: 9000000100009033 <SF,HV,EE,ME,IR,DR,RI,LE,TM[E]>
[ 7072.863667]   CR: 44082882  XER: 20000000
[ 7072.863767] CFAR: c0000000000e2e38 DAR: d000000c250c00f8 DSISR: 42000000 SOFTE: 1
GPR00: c0000000000e2e3c c000001e3ffef7e0 c000000001407d00 d000000c250c00f0
GPR04: d00000006509fb70 d00000000b3d2048 0000000003ffdfb7 0000000000000000
GPR08: 00000001007fdfb7 00000000c000000f d0000000250c0000 000000000070f7bf
GPR12: 0000000000000008 c00000000fdad000 0000000010879478 00000000105a0d78
GPR16: 00007ffaf4080000 0000000000001190 0000000000000000 0000000000010000
GPR20: 4001ffffff000415 d00000006509fb70 0000000004091190 0000000ee1881190
GPR24: 0000000003ffdfb7 0000000003ffdfb7 00000000007fdfb7 c000000f5c958000
GPR28: d00000002d09fb70 0000000003ffdfb7 d00000006509fb70 d00000000b3d2048
[ 7072.864439] NIP [c0000000000e1c78] kvmppc_add_revmap_chain+0x88/0x130
[ 7072.864503] LR [c0000000000e2e3c] kvmppc_do_h_enter+0x84c/0x9e0
[ 7072.864566] Call Trace:
[ 7072.864594] [c000001e3ffef7e0] [c000001e3ffef830] 0xc000001e3ffef830 (unreliable)
[ 7072.864671] [c000001e3ffef830] [c0000000000e2e3c] kvmppc_do_h_enter+0x84c/0x9e0
[ 7072.864751] [c000001e3ffef920] [d00000000b38d878] kvmppc_map_vrma+0x168/0x200 [kvm_hv]
[ 7072.864831] [c000001e3ffef9e0] [d00000000b38a684] kvmppc_vcpu_run_hv+0x1284/0x1300 [kvm_hv]
[ 7072.864914] [c000001e3ffefb30] [d00000000f465664] kvmppc_vcpu_run+0x44/0x60 [kvm]
[ 7072.865008] [c000001e3ffefb60] [d00000000f461864] kvm_arch_vcpu_ioctl_run+0x114/0x290 [kvm]
[ 7072.865152] [c000001e3ffefbe0] [d00000000f453c98] kvm_vcpu_ioctl+0x598/0x7a0 [kvm]
[ 7072.865292] [c000001e3ffefd40] [c000000000389328] do_vfs_ioctl+0xd8/0x8c0
[ 7072.865410] [c000001e3ffefde0] [c000000000389be4] SyS_ioctl+0xd4/0x130
[ 7072.865526] [c000001e3ffefe30] [c00000000000b760] system_call+0x58/0x6c
[ 7072.865644] Instruction dump:
[ 7072.865715] e95b2110 793a0020 7b4926e4 7f8a4a14 409e0098 807c000c 786326e4 7c6a1a14
[ 7072.865857] 935e0008 7bbd0020 813c000c 913e000c <93a30008> 93bc000c 48000038 60000000
[ 7072.866001] ---[ end trace 627b6e4bf8080edc ]---

Note that to trigger this, it is necessary to use a recent upstream
QEMU (or other userspace that resizes the HPT at CAS time), specify
a maximum memory size substantially larger than the current memory
size, and boot a guest kernel that does not support HPT resizing.

This fixes the problem by resetting the rmap arrays when the old HPT
is freed.

Fixes: f98a8bf9ee ("KVM: PPC: Book3S HV: Allow KVM_PPC_ALLOCATE_HTAB ioctl() to change HPT size")
Cc: stable@vger.kernel.org # v4.11+
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-07-24 16:10:44 +10:00
Paul Mackerras
e470571514 KVM: PPC: Book3S HV: Enable TM before accessing TM registers
Commit 46a704f840 ("KVM: PPC: Book3S HV: Preserve userspace HTM state
properly", 2017-06-15) added code to read transactional memory (TM)
registers but forgot to enable TM before doing so.  The result is
that if userspace does have live values in the TM registers, a KVM_RUN
ioctl will cause a host kernel crash like this:

[  181.328511] Unrecoverable TM Unavailable Exception f60 at d00000001e7d9980
[  181.328605] Oops: Unrecoverable TM Unavailable Exception, sig: 6 [#1]
[  181.328613] SMP NR_CPUS=2048
[  181.328613] NUMA
[  181.328618] PowerNV
[  181.328646] Modules linked in: vhost_net vhost tap nfs_layout_nfsv41_files rpcsec_gss_krb5 nfsv4 dns_resolver nfs
+fscache xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_nat
+nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 tun ebtable_filter ebtables
+ip6table_filter ip6_tables iptable_filter bridge stp llc kvm_hv kvm nfsd ses enclosure scsi_transport_sas ghash_generic
+auth_rpcgss gf128mul xts sg ctr nfs_acl lockd vmx_crypto shpchp ipmi_powernv i2c_opal grace ipmi_devintf i2c_core
+powernv_rng sunrpc ipmi_msghandler ibmpowernv uio_pdrv_genirq uio leds_powernv powernv_op_panel ip_tables xfs sd_mod
+lpfc ipr bnx2x libata mdio ptp pps_core scsi_transport_fc libcrc32c dm_mirror dm_region_hash dm_log dm_mod
[  181.329278] CPU: 40 PID: 9926 Comm: CPU 0/KVM Not tainted 4.12.0+ #1
[  181.329337] task: c000003fc6980000 task.stack: c000003fe4d80000
[  181.329396] NIP: d00000001e7d9980 LR: d00000001e77381c CTR: d00000001e7d98f0
[  181.329465] REGS: c000003fe4d837e0 TRAP: 0f60   Not tainted  (4.12.0+)
[  181.329523] MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE>
[  181.329527]   CR: 24022448  XER: 00000000
[  181.329608] CFAR: d00000001e773818 SOFTE: 1
[  181.329608] GPR00: d00000001e77381c c000003fe4d83a60 d00000001e7ef410 c000003fdcfe0000
[  181.329608] GPR04: c000003fe4f00000 0000000000000000 0000000000000000 c000003fd7954800
[  181.329608] GPR08: 0000000000000001 c000003fc6980000 0000000000000000 d00000001e7e2880
[  181.329608] GPR12: d00000001e7d98f0 c000000007b19000 00000001295220e0 00007fffc0ce2090
[  181.329608] GPR16: 0000010011886608 00007fff8c89f260 0000000000000001 00007fff8c080028
[  181.329608] GPR20: 0000000000000000 00000100118500a6 0000010011850000 0000010011850000
[  181.329608] GPR24: 00007fffc0ce1b48 0000010011850000 00000000d673b901 0000000000000000
[  181.329608] GPR28: 0000000000000000 c000003fdcfe0000 c000003fdcfe0000 c000003fe4f00000
[  181.330199] NIP [d00000001e7d9980] kvmppc_vcpu_run_hv+0x90/0x6b0 [kvm_hv]
[  181.330264] LR [d00000001e77381c] kvmppc_vcpu_run+0x2c/0x40 [kvm]
[  181.330322] Call Trace:
[  181.330351] [c000003fe4d83a60] [d00000001e773478] kvmppc_set_one_reg+0x48/0x340 [kvm] (unreliable)
[  181.330437] [c000003fe4d83b30] [d00000001e77381c] kvmppc_vcpu_run+0x2c/0x40 [kvm]
[  181.330513] [c000003fe4d83b50] [d00000001e7700b4] kvm_arch_vcpu_ioctl_run+0x114/0x2a0 [kvm]
[  181.330586] [c000003fe4d83bd0] [d00000001e7642f8] kvm_vcpu_ioctl+0x598/0x7a0 [kvm]
[  181.330658] [c000003fe4d83d40] [c0000000003451b8] do_vfs_ioctl+0xc8/0x8b0
[  181.330717] [c000003fe4d83de0] [c000000000345a64] SyS_ioctl+0xc4/0x120
[  181.330776] [c000003fe4d83e30] [c00000000000b004] system_call+0x58/0x6c
[  181.330833] Instruction dump:
[  181.330869] e92d0260 e9290b50 e9290108 792807e3 41820058 e92d0260 e9290b50 e9290108
[  181.330941] 792ae8a4 794a1f87 408204f4 e92d0260 <7d4022a6> f9490ff0 e92d0260 7d4122a6
[  181.331013] ---[ end trace 6f6ddeb4bfe92a92 ]---

The fix is just to turn on the TM bit in the MSR before accessing the
registers.

Cc: stable@vger.kernel.org # v3.14+
Fixes: 46a704f840 ("KVM: PPC: Book3S HV: Preserve userspace HTM state properly")
Reported-by: Jan Stancek <jstancek@redhat.com>
Tested-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2017-07-24 16:10:44 +10:00
Michal Hocko
dcda9b0471 mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic
__GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to
the page allocator.  This has been true but only for allocations
requests larger than PAGE_ALLOC_COSTLY_ORDER.  It has been always
ignored for smaller sizes.  This is a bit unfortunate because there is
no way to express the same semantic for those requests and they are
considered too important to fail so they might end up looping in the
page allocator for ever, similarly to GFP_NOFAIL requests.

Now that the whole tree has been cleaned up and accidental or misled
usage of __GFP_REPEAT flag has been removed for !costly requests we can
give the original flag a better name and more importantly a more useful
semantic.  Let's rename it to __GFP_RETRY_MAYFAIL which tells the user
that the allocator would try really hard but there is no promise of a
success.  This will work independent of the order and overrides the
default allocator behavior.  Page allocator users have several levels of
guarantee vs.  cost options (take GFP_KERNEL as an example)

 - GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_
   attempt to free memory at all. The most light weight mode which even
   doesn't kick the background reclaim. Should be used carefully because
   it might deplete the memory and the next user might hit the more
   aggressive reclaim

 - GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic
   allocation without any attempt to free memory from the current
   context but can wake kswapd to reclaim memory if the zone is below
   the low watermark. Can be used from either atomic contexts or when
   the request is a performance optimization and there is another
   fallback for a slow path.

 - (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) -
   non sleeping allocation with an expensive fallback so it can access
   some portion of memory reserves. Usually used from interrupt/bh
   context with an expensive slow path fallback.

 - GFP_KERNEL - both background and direct reclaim are allowed and the
   _default_ page allocator behavior is used. That means that !costly
   allocation requests are basically nofail but there is no guarantee of
   that behavior so failures have to be checked properly by callers
   (e.g. OOM killer victim is allowed to fail currently).

 - GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior
   and all allocation requests fail early rather than cause disruptive
   reclaim (one round of reclaim in this implementation). The OOM killer
   is not invoked.

 - GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator
   behavior and all allocation requests try really hard. The request
   will fail if the reclaim cannot make any progress. The OOM killer
   won't be triggered.

 - GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior
   and all allocation requests will loop endlessly until they succeed.
   This might be really dangerous especially for larger orders.

Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL
because they already had their semantic.  No new users are added.
__alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if
there is no progress and we have already passed the OOM point.

This means that all the reclaim opportunities have been exhausted except
the most disruptive one (the OOM killer) and a user defined fallback
behavior is more sensible than keep retrying in the page allocator.

[akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c]
[mhocko@suse.com: semantic fix]
  Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz
[mhocko@kernel.org: address other thing spotted by Vlastimil]
  Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:03 -07:00