Commit Graph

940 Commits

Author SHA1 Message Date
Jim Mattson
355f4fb140 kvm: nVMX: VMCLEAR an active shadow VMCS after last use
After a successful VM-entry with the "VMCS shadowing" VM-execution
control set, the shadow VMCS referenced by the VMCS link pointer field
in the current VMCS becomes active on the logical processor.

A VMCS that is made active on more than one logical processor may become
corrupted. Therefore, before an active VMCS can be migrated to another
logical processor, the first logical processor must execute a VMCLEAR
for the active VMCS. VMCLEAR both ensures that all VMCS data are written
to memory and makes the VMCS inactive.

Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-By: David Matlack <dmatlack@google.com>
Message-Id: <1477668579-22555-1-git-send-email-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 20:03:17 +01:00
Paolo Bonzini
ea26e4ec08 KVM: x86: drop TSC offsetting kvm_x86_ops to fix KVM_GET/SET_CLOCK
Since commit a545ab6a00 ("kvm: x86: add tsc_offset field to struct
kvm_vcpu_arch", 2016-09-07) the offset between host and L1 TSC is
cached and need not be fished out of the VMCS or VMCB.  This means
that we can implement adjust_tsc_offset_guest and read_l1_tsc
entirely in generic code.  The simplification is particularly
significant for VMX code, where vmx->nested.vmcs01_tsc_offset
was duplicating what is now in vcpu->arch.tsc_offset.  Therefore
the vmcs01_tsc_offset can be dropped completely.

More importantly, this fixes KVM_GET_CLOCK/KVM_SET_CLOCK
which, after commit 108b249c45 ("KVM: x86: introduce get_kvmclock_ns",
2016-09-01) called read_l1_tsc while the VMCS was not loaded.
It thus returned bogus values on Intel CPUs.

Fixes: 108b249c45
Reported-by: Roman Kagan <rkagan@virtuozzo.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-11-02 20:03:07 +01:00
Jim Mattson
85c856b39b kvm: nVMX: Fix kernel panics induced by illegal INVEPT/INVVPID types
Bitwise shifts by amounts greater than or equal to the width of the left
operand are undefined. A malicious guest can exploit this to crash a
32-bit host, due to the BUG_ON(1)'s in handle_{invept,invvpid}.

Signed-off-by: Jim Mattson <jmattson@google.com>
Message-Id: <1477496318-17681-1-git-send-email-jmattson@google.com>
[Change 1UL to 1, to match the range check on the shift count. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-10-27 12:15:27 +02:00
Linus Torvalds
6218590bcb KVM updates for v4.9-rc1
All architectures:
   Move `make kvmconfig` stubs from x86;  use 64 bits for debugfs stats.
 
 ARM:
   Important fixes for not using an in-kernel irqchip; handle SError
   exceptions and present them to guests if appropriate; proxying of GICV
   access at EL2 if guest mappings are unsafe; GICv3 on AArch32 on ARMv8;
   preparations for GICv3 save/restore, including ABI docs; cleanups and
   a bit of optimizations.
 
 MIPS:
   A couple of fixes in preparation for supporting MIPS EVA host kernels;
   MIPS SMP host & TLB invalidation fixes.
 
 PPC:
   Fix the bug which caused guests to falsely report lockups; other minor
   fixes; a small optimization.
 
 s390:
   Lazy enablement of runtime instrumentation; up to 255 CPUs for nested
   guests; rework of machine check deliver; cleanups and fixes.
 
 x86:
   IOMMU part of AMD's AVIC for vmexit-less interrupt delivery; Hyper-V
   TSC page; per-vcpu tsc_offset in debugfs; accelerated INS/OUTS in
   nVMX; cleanups and fixes.
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Merge tag 'kvm-4.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Radim Krčmář:
 "All architectures:
   - move `make kvmconfig` stubs from x86
   - use 64 bits for debugfs stats

  ARM:
   - Important fixes for not using an in-kernel irqchip
   - handle SError exceptions and present them to guests if appropriate
   - proxying of GICV access at EL2 if guest mappings are unsafe
   - GICv3 on AArch32 on ARMv8
   - preparations for GICv3 save/restore, including ABI docs
   - cleanups and a bit of optimizations

  MIPS:
   - A couple of fixes in preparation for supporting MIPS EVA host
     kernels
   - MIPS SMP host & TLB invalidation fixes

  PPC:
   - Fix the bug which caused guests to falsely report lockups
   - other minor fixes
   - a small optimization

  s390:
   - Lazy enablement of runtime instrumentation
   - up to 255 CPUs for nested guests
   - rework of machine check deliver
   - cleanups and fixes

  x86:
   - IOMMU part of AMD's AVIC for vmexit-less interrupt delivery
   - Hyper-V TSC page
   - per-vcpu tsc_offset in debugfs
   - accelerated INS/OUTS in nVMX
   - cleanups and fixes"

* tag 'kvm-4.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (140 commits)
  KVM: MIPS: Drop dubious EntryHi optimisation
  KVM: MIPS: Invalidate TLB by regenerating ASIDs
  KVM: MIPS: Split kernel/user ASID regeneration
  KVM: MIPS: Drop other CPU ASIDs on guest MMU changes
  KVM: arm/arm64: vgic: Don't flush/sync without a working vgic
  KVM: arm64: Require in-kernel irqchip for PMU support
  KVM: PPC: Book3s PR: Allow access to unprivileged MMCR2 register
  KVM: PPC: Book3S PR: Support 64kB page size on POWER8E and POWER8NVL
  KVM: PPC: Book3S: Remove duplicate setting of the B field in tlbie
  KVM: PPC: BookE: Fix a sanity check
  KVM: PPC: Book3S HV: Take out virtual core piggybacking code
  KVM: PPC: Book3S: Treat VTB as a per-subcore register, not per-thread
  ARM: gic-v3: Work around definition of gic_write_bpr1
  KVM: nVMX: Fix the NMI IDT-vectoring handling
  KVM: VMX: Enable MSR-BASED TPR shadow even if APICv is inactive
  KVM: nVMX: Fix reload apic access page warning
  kvmconfig: add virtio-gpu to config fragment
  config: move x86 kvm_guest.config to a common location
  arm64: KVM: Remove duplicating init code for setting VMID
  ARM: KVM: Support vgic-v3
  ...
2016-10-06 10:49:01 -07:00
Wanpeng Li
c5a6d5f7fa KVM: nVMX: Fix the NMI IDT-vectoring handling
Run kvm-unit-tests/eventinj.flat in L1:

Sending NMI to self
After NMI to self
FAIL: NMI

This test scenario is to test whether VMM can handle NMI IDT-vectoring info correctly.

At the beginning, L2 writes LAPIC to send a self NMI, the EPT page tables on both L1
and L0 are empty so:

- The L2 accesses memory can generate EPT violation which can be intercepted by L0.

  The EPT violation vmexit occurred during delivery of this NMI, and the NMI info is
  recorded in vmcs02's IDT-vectoring info.

- L0 walks L1's EPT12 and L0 sees the mapping is invalid, it injects the EPT violation into L1.

  The vmcs02's IDT-vectoring info is reflected to vmcs12's IDT-vectoring info since
  it is a nested vmexit.

- L1 receives the EPT violation, then fixes its EPT12.
- L1 executes VMRESUME to resume L2 which generates vmexit and causes L1 exits to L0.
- L0 emulates VMRESUME which is called from L1, then return to L2.

  L0 merges the requirement of vmcs12's IDT-vectoring info and injects it to L2 through
  vmcs02.

- The L2 re-executes the fault instruction and cause EPT violation again.
- Since the L1's EPT12 is valid, L0 can fix its EPT02
- L0 resume L2

  The EPT violation vmexit occurred during delivery of this NMI again, and the NMI info
  is recorded in vmcs02's IDT-vectoring info. L0 should inject the NMI through vmentry
  event injection since it is caused by EPT02's EPT violation.

However, vmx_inject_nmi() refuses to inject NMI from IDT-vectoring info if vCPU is in
guest mode, this patch fix it by permitting to inject NMI from IDT-vectoring if it is
the L0's responsibility to inject NMI from IDT-vectoring info to L2.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Bandan Das <bsd@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-09-23 01:08:15 +02:00
Wanpeng Li
f6e90f9e0e KVM: VMX: Enable MSR-BASED TPR shadow even if APICv is inactive
I observed that kvmvapic(to optimize flexpriority=N or AMD) is used
to boost TPR access when testing kvm-unit-test/eventinj.flat tpr case
on my haswell desktop (w/ flexpriority, w/o APICv). Commit (8d14695f95
x86, apicv: add virtual x2apic support) disable virtual x2apic mode
completely if w/o APICv, and the author also told me that windows guest
can't enter into x2apic mode when he developed the APICv feature several
years ago. However, it is not truth currently, Interrupt Remapping and
vIOMMU is added to qemu and the developers from Intel test windows 8 can
work in x2apic mode w/ Interrupt Remapping enabled recently.

This patch enables TPR shadow for virtual x2apic mode to boost
windows guest in x2apic mode even if w/o APICv.

Can pass the kvm-unit-test.

Suggested-by: Radim Krčmář <rkrcmar@redhat.com>
Suggested-by: Wincy Van <fanwenyi0529@gmail.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Wincy Van <fanwenyi0529@gmail.com>
Cc: Yang Zhang <yang.zhang.wz@gmail.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-09-23 01:08:14 +02:00
Wanpeng Li
c83b6d1594 KVM: nVMX: Fix reload apic access page warning
WARNING: CPU: 1 PID: 4230 at kernel/sched/core.c:7564 __might_sleep+0x7e/0x80
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8d0de7f9>] prepare_to_swait+0x39/0xa0
CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
Call Trace:
 dump_stack+0x99/0xd0
 __warn+0xd1/0xf0
 warn_slowpath_fmt+0x4f/0x60
 ? prepare_to_swait+0x39/0xa0
 ? prepare_to_swait+0x39/0xa0
 __might_sleep+0x7e/0x80
 __gfn_to_pfn_memslot+0x156/0x480 [kvm]
 gfn_to_pfn+0x2a/0x30 [kvm]
 gfn_to_page+0xe/0x20 [kvm]
 kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
 nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
 ? _raw_spin_unlock_irqrestore+0x36/0x80
 vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
 kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
 kvm_vcpu_check_block+0x12/0x60 [kvm]
 kvm_vcpu_block+0x94/0x4c0 [kvm]
 kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
 ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
 kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]

===============================
[ INFO: suspicious RCU usage. ]
4.8.0-rc5+ #47 Not tainted
-------------------------------
./include/linux/kvm_host.h:535 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
1 lock held by qemu-system-x86/4230:
 #0:  (&vcpu->mutex){+.+.+.}, at: [<ffffffffc062975c>] vcpu_load+0x1c/0x60 [kvm]

stack backtrace:
CPU: 1 PID: 4230 Comm: qemu-system-x86 Not tainted 4.8.0-rc5+ #47
Call Trace:
 dump_stack+0x99/0xd0
 lockdep_rcu_suspicious+0xe7/0x120
 gfn_to_memslot+0x12a/0x140 [kvm]
 gfn_to_pfn+0x12/0x30 [kvm]
 gfn_to_page+0xe/0x20 [kvm]
 kvm_vcpu_reload_apic_access_page+0x32/0xa0 [kvm]
 nested_vmx_vmexit+0x765/0xca0 [kvm_intel]
 ? _raw_spin_unlock_irqrestore+0x36/0x80
 vmx_check_nested_events+0x49/0x1f0 [kvm_intel]
 kvm_arch_vcpu_runnable+0x2d/0xe0 [kvm]
 kvm_vcpu_check_block+0x12/0x60 [kvm]
 kvm_vcpu_block+0x94/0x4c0 [kvm]
 kvm_arch_vcpu_ioctl_run+0x619/0x1aa0 [kvm]
 ? kvm_arch_vcpu_ioctl_run+0xdf1/0x1aa0 [kvm]
 kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
 ? __fget+0xfd/0x210
 ? __lock_is_held+0x54/0x70
 do_vfs_ioctl+0x96/0x6a0
 ? __fget+0x11c/0x210
 ? __fget+0x5/0x210
 SyS_ioctl+0x79/0x90
 do_syscall_64+0x81/0x220
 entry_SYSCALL64_slow_path+0x25/0x25

These can be triggered by running kvm-unit-test: ./x86-run x86/vmx.flat

The nested preemption timer is based on hrtimer which is started on L2
entry, stopped on L2 exit and evaluated via the new check_nested_events
hook. The current logic adds vCPU to a simple waitqueue (TASK_INTERRUPTIBLE)
if need to yield pCPU and w/o holding srcu read lock when accesses memslots,
both can be in nested preemption timer evaluation path which results in
the warning above.

This patch fix it by leveraging request bit to async reload APIC access
page before vmentry in order to avoid to reload directly during the nested
preemption timer evaluation, it is safe since the vmcs01 is loaded and
current is nested vmexit.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-09-23 01:08:13 +02:00
Luiz Capitulino
3e3f50262e kvm: x86: drop read_tsc_offset()
The TSC offset can now be read directly from struct kvm_arch_vcpu.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-16 16:57:45 +02:00
Ingo Molnar
d4b80afbba Merge branch 'linus' into x86/asm, to pick up recent fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-15 08:24:53 +02:00
Jan Dakinevich
9ac7e3e815 KVM: nVMX: expose INS/OUTS information support
Expose the feature to L1 hypervisor if host CPU supports it, since
certain hypervisors requires it for own purposes.

According to Intel SDM A.1, if CPU supports the feature,
VMX_INSTRUCTION_INFO field of VMCS will contain detailed information
about INS/OUTS instructions handling. This field is already copied to
VMCS12 for L1 hypervisor (see prepare_vmcs12 routine) independently
feature presence.

Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-07 19:34:30 +02:00
Paolo Bonzini
16cb025565 KVM: VMX: not use vmcs_config in setup_vmcs_config
setup_vmcs_config takes a pointer to the vmcs_config global.  The
indirection is somewhat pointless, but just keep things consistent
for now.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-07 19:34:30 +02:00
Paolo Bonzini
bbe41b9508 KVM: x86: ratelimit and decrease severity for guest-triggered printk
These are mostly related to nested VMX.  They needn't have
a loglevel as high as KERN_WARN, and mustn't be allowed to
pollute the host logs.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-07 19:34:29 +02:00
Jan Dakinevich
119a9c01a5 KVM: nVMX: pass valid guest linear-address to the L1
If EPT support is exposed to L1 hypervisor, guest linear-address field
of VMCS should contain GVA of L2, the access to which caused EPT violation.

Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-07 19:34:28 +02:00
Wanpeng Li
f15a75eedc KVM: nVMX: make emulated nested preemption timer pinned
Commit 61abdbe0bc ("kvm: x86: make lapic hrtimer pinned") pins the emulated
lapic timer. This patch does the same for the emulated nested preemption
timer to avoid vmexit an unrelated vCPU and the latency of kicking IPI to
another vCPU.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-07 19:34:27 +02:00
Liang Li
72e0ae58a0 vmx: refine validity check for guest linear address
The validity check for the guest line address is inefficient,
check the invalid value instead of enumerating the valid ones.

Signed-off-by: Liang Li <liang.z.li@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-07 19:34:27 +02:00
Peter Feiner
c95ba92afb kvm: nVMX: fix nested tsc scaling
When the host supported TSC scaling, L2 would use a TSC multiplier of
0, which causes a VM entry failure. Now L2's TSC uses the same
multiplier as L1.

Signed-off-by: Peter Feiner <pfeiner@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-18 12:19:09 +02:00
Radim Krčmář
dccbfcf52c KVM: nVMX: postpone VMCS changes on MSR_IA32_APICBASE write
If vmcs12 does not intercept APIC_BASE writes, then KVM will handle the
write with vmcs02 as the current VMCS.
This will incorrectly apply modifications intended for vmcs01 to vmcs02
and L2 can use it to gain access to L0's x2APIC registers by disabling
virtualized x2APIC while using msr bitmap that assumes enabled.

Postpone execution of vmx_set_virtual_x2apic_mode until vmcs01 is the
current VMCS.  An alternative solution would temporarily make vmcs01 the
current VMCS, but it requires more care.

Fixes: 8d14695f95 ("x86, apicv: add virtual x2apic support")
Reported-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-08-18 12:19:08 +02:00
Radim Krčmář
d048c09821 KVM: nVMX: fix msr bitmaps to prevent L2 from accessing L0 x2APIC
msr bitmap can be used to avoid a VM exit (interception) on guest MSR
accesses.  In some configurations of VMX controls, the guest can even
directly access host's x2APIC MSRs.  See SDM 29.5 VIRTUALIZING MSR-BASED
APIC ACCESSES.

L2 could read all L0's x2APIC MSRs and write TPR, EOI, and SELF_IPI.
To do so, L1 would first trick KVM to disable all possible interceptions
by enabling APICv features and then would turn those features off;
nested_vmx_merge_msr_bitmap() only disabled interceptions, so VMX would
not intercept previously enabled MSRs even though they were not safe
with the new configuration.

Correctly re-enabling interceptions is not enough as a second bug would
still allow L1+L2 to access host's MSRs: msr bitmap was shared for all
VMCSs, so L1 could trigger a race to get the desired combination of msr
bitmap and VMX controls.

This fix allocates a msr bitmap for every L1 VCPU, allows only safe
x2APIC MSRs from L1's msr bitmap, and disables msr bitmaps if they would
have to intercept everything anyway.

Fixes: 3af18d9c5f ("KVM: nVMX: Prepare for using hardware MSR bitmap")
Reported-by: Jim Mattson <jmattson@google.com>
Suggested-by: Wincy Van <fanwenyi0529@gmail.com>
Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-08-18 12:19:07 +02:00
Kees Cook
404f6aac9b x86: Apply more __ro_after_init and const
Guided by grsecurity's analogous __read_only markings in arch/x86,
this applies several uses of __ro_after_init to structures that are
only updated during __init, and const for some structures that are
never updated.  Additionally extends __init markings to some functions
that are only used during __init, and cleans up some missing C99 style
static initializers.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Brown <david.brown@linaro.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Emese Revfy <re.emese@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-hardening@lists.openwall.com
Link: http://lkml.kernel.org/r/20160808232906.GA29731@www.outflux.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-08-10 14:55:05 +02:00
Bandan Das
45e11817d5 nvmx: mark ept single context invalidation as supported
Commit 4b85507860 ("KVM: nVMX: Don't advertise single
context invalidation for invept") removed advertising
single context invalidation since the spec does not mandate it.
However, some hypervisors (such as ESX) require it to be present
before willing to use ept in a nested environment. Advertise it
and fallback to the global case.

Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-04 14:21:52 +02:00
Bandan Das
03331b4b8b nvmx: remove comment about missing nested vpid support
Nested vpid is already supported and both single/global
modes are advertised to the guest

Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-04 14:21:51 +02:00
Linus Torvalds
221bb8a46e - ARM: GICv3 ITS emulation and various fixes. Removal of the old
VGIC implementation.
 
 - s390: support for trapping software breakpoints, nested virtualization
 (vSIE), the STHYI opcode, initial extensions for CPU model support.
 
 - MIPS: support for MIPS64 hosts (32-bit guests only) and lots of cleanups,
 preliminary to this and the upcoming support for hardware virtualization
 extensions.
 
 - x86: support for execute-only mappings in nested EPT; reduced vmexit
 latency for TSC deadline timer (by about 30%) on Intel hosts; support for
 more than 255 vCPUs.
 
 - PPC: bugfixes.
 
 The ugly bit is the conflicts.  A couple of them are simple conflicts due
 to 4.7 fixes, but most of them are with other trees. There was definitely
 too much reliance on Acked-by here.  Some conflicts are for KVM patches
 where _I_ gave my Acked-by, but the worst are for this pull request's
 patches that touch files outside arch/*/kvm.  KVM submaintainers should
 probably learn to synchronize better with arch maintainers, with the
 latter providing topic branches whenever possible instead of Acked-by.
 This is what we do with arch/x86.  And I should learn to refuse pull
 requests when linux-next sends scary signals, even if that means that
 submaintainers have to rebase their branches.
 
 Anyhow, here's the list:
 
 - arch/x86/kvm/vmx.c: handle_pcommit and EXIT_REASON_PCOMMIT was removed
 by the nvdimm tree.  This tree adds handle_preemption_timer and
 EXIT_REASON_PREEMPTION_TIMER at the same place.  In general all mentions
 of pcommit have to go.
 
 There is also a conflict between a stable fix and this patch, where the
 stable fix removed the vmx_create_pml_buffer function and its call.
 
 - virt/kvm/kvm_main.c: kvm_cpu_notifier was removed by the hotplug tree.
 This tree adds kvm_io_bus_get_dev at the same place.
 
 - virt/kvm/arm/vgic.c: a few final bugfixes went into 4.7 before the
 file was completely removed for 4.8.
 
 - include/linux/irqchip/arm-gic-v3.h: this one is entirely our fault;
 this is a change that should have gone in through the irqchip tree and
 pulled by kvm-arm.  I think I would have rejected this kvm-arm pull
 request.  The KVM version is the right one, except that it lacks
 GITS_BASER_PAGES_SHIFT.
 
 - arch/powerpc: what a mess.  For the idle_book3s.S conflict, the KVM
 tree is the right one; everything else is trivial.  In this case I am
 not quite sure what went wrong.  The commit that is causing the mess
 (fd7bacbca4, "KVM: PPC: Book3S HV: Fix TB corruption in guest exit
 path on HMI interrupt", 2016-05-15) touches both arch/powerpc/kernel/
 and arch/powerpc/kvm/.  It's large, but at 396 insertions/5 deletions
 I guessed that it wasn't really possible to split it and that the 5
 deletions wouldn't conflict.  That wasn't the case.
 
 - arch/s390: also messy.  First is hypfs_diag.c where the KVM tree
 moved some code and the s390 tree patched it.  You have to reapply the
 relevant part of commits 6c22c98637, plus all of e030c1125e, to
 arch/s390/kernel/diag.c.  Or pick the linux-next conflict
 resolution from http://marc.info/?l=kvm&m=146717549531603&w=2.
 Second, there is a conflict in gmap.c between a stable fix and 4.8.
 The KVM version here is the correct one.
 
 I have pushed my resolution at refs/heads/merge-20160802 (commit
 3d1f53419842) at git://git.kernel.org/pub/scm/virt/kvm/kvm.git.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:

 - ARM: GICv3 ITS emulation and various fixes.  Removal of the
   old VGIC implementation.

 - s390: support for trapping software breakpoints, nested
   virtualization (vSIE), the STHYI opcode, initial extensions
   for CPU model support.

 - MIPS: support for MIPS64 hosts (32-bit guests only) and lots
   of cleanups, preliminary to this and the upcoming support for
   hardware virtualization extensions.

 - x86: support for execute-only mappings in nested EPT; reduced
   vmexit latency for TSC deadline timer (by about 30%) on Intel
   hosts; support for more than 255 vCPUs.

 - PPC: bugfixes.

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (302 commits)
  KVM: PPC: Introduce KVM_CAP_PPC_HTM
  MIPS: Select HAVE_KVM for MIPS64_R{2,6}
  MIPS: KVM: Reset CP0_PageMask during host TLB flush
  MIPS: KVM: Fix ptr->int cast via KVM_GUEST_KSEGX()
  MIPS: KVM: Sign extend MFC0/RDHWR results
  MIPS: KVM: Fix 64-bit big endian dynamic translation
  MIPS: KVM: Fail if ebase doesn't fit in CP0_EBase
  MIPS: KVM: Use 64-bit CP0_EBase when appropriate
  MIPS: KVM: Set CP0_Status.KX on MIPS64
  MIPS: KVM: Make entry code MIPS64 friendly
  MIPS: KVM: Use kmap instead of CKSEG0ADDR()
  MIPS: KVM: Use virt_to_phys() to get commpage PFN
  MIPS: Fix definition of KSEGX() for 64-bit
  KVM: VMX: Add VMCS to CPU's loaded VMCSs before VMPTRLD
  kvm: x86: nVMX: maintain internal copy of current VMCS
  KVM: PPC: Book3S HV: Save/restore TM state in H_CEDE
  KVM: PPC: Book3S HV: Pull out TM state save/restore into separate procedures
  KVM: arm64: vgic-its: Simplify MAPI error handling
  KVM: arm64: vgic-its: Make vgic_its_cmd_handle_mapi similar to other handlers
  KVM: arm64: vgic-its: Turn device_id validation into generic ID validation
  ...
2016-08-02 16:11:27 -04:00
Jim Mattson
b80c76ec98 KVM: VMX: Add VMCS to CPU's loaded VMCSs before VMPTRLD
Kexec needs to know the addresses of all VMCSs that are active on
each CPU, so that it can flush them from the VMCS caches. It is
safe to record superfluous addresses that are not associated with
an active VMCS, but it is not safe to omit an address associated
with an active VMCS.

After a call to vmcs_load, the VMCS that was loaded is active on
the CPU. The VMCS should be added to the CPU's list of active
VMCSs before it is loaded.

Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-08-01 15:14:24 +02:00
David Matlack
4f2777bc97 kvm: x86: nVMX: maintain internal copy of current VMCS
KVM maintains L1's current VMCS in guest memory, at the guest physical
page identified by the argument to VMPTRLD. This makes hairy
time-of-check to time-of-use bugs possible,as VCPUs can be writing
the the VMCS page in memory while KVM is emulating VMLAUNCH and
VMRESUME.

The spec documents that writing to the VMCS page while it is loaded is
"undefined". Therefore it is reasonable to load the entire VMCS into
an internal cache during VMPTRLD and ignore writes to the VMCS page
-- the guest should be using VMREAD and VMWRITE to access the current
VMCS.

To adhere to the spec, KVM should flush the current VMCS during VMPTRLD,
and the target VMCS during VMCLEAR (as given by the operand to VMCLEAR).
Since this implementation of VMCS caching only maintains the the current
VMCS, VMCLEAR will only do a flush if the operand to VMCLEAR is the
current VMCS pointer.

KVM will also flush during VMXOFF, which is not mandated by the spec,
but also not in conflict with the spec.

Signed-off-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-08-01 14:49:05 +02:00
Linus Torvalds
f0c98ebc57 libnvdimm for 4.8
1/ Replace pcommit with ADR / directed-flushing:
    The pcommit instruction, which has not shipped on any product, is
    deprecated. Instead, the requirement is that platforms implement either
    ADR, or provide one or more flush addresses per nvdimm. ADR
    (Asynchronous DRAM Refresh) flushes data in posted write buffers to the
    memory controller on a power-fail event. Flush addresses are defined in
    ACPI 6.x as an NVDIMM Firmware Interface Table (NFIT) sub-structure:
    "Flush Hint Address Structure". A flush hint is an mmio address that
    when written and fenced assures that all previous posted writes
    targeting a given dimm have been flushed to media.
 
 2/ On-demand ARS (address range scrub):
    Linux uses the results of the ACPI ARS commands to track bad blocks
    in pmem devices.  When latent errors are detected we re-scrub the media
    to refresh the bad block list, userspace can also request a re-scrub at
    any time.
 
 3/ Support for the Microsoft DSM (device specific method) command format.
 
 4/ Support for EDK2/OVMF virtual disk device memory ranges.
 
 5/ Various fixes and cleanups across the subsystem.
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Merge tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:

 - Replace pcommit with ADR / directed-flushing.

   The pcommit instruction, which has not shipped on any product, is
   deprecated.  Instead, the requirement is that platforms implement
   either ADR, or provide one or more flush addresses per nvdimm.

   ADR (Asynchronous DRAM Refresh) flushes data in posted write buffers
   to the memory controller on a power-fail event.

   Flush addresses are defined in ACPI 6.x as an NVDIMM Firmware
   Interface Table (NFIT) sub-structure: "Flush Hint Address Structure".
   A flush hint is an mmio address that when written and fenced assures
   that all previous posted writes targeting a given dimm have been
   flushed to media.

 - On-demand ARS (address range scrub).

   Linux uses the results of the ACPI ARS commands to track bad blocks
   in pmem devices.  When latent errors are detected we re-scrub the
   media to refresh the bad block list, userspace can also request a
   re-scrub at any time.

 - Support for the Microsoft DSM (device specific method) command
   format.

 - Support for EDK2/OVMF virtual disk device memory ranges.

 - Various fixes and cleanups across the subsystem.

* tag 'libnvdimm-for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (41 commits)
  libnvdimm-btt: Delete an unnecessary check before the function call "__nd_device_register"
  nfit: do an ARS scrub on hitting a latent media error
  nfit: move to nfit/ sub-directory
  nfit, libnvdimm: allow an ARS scrub to be triggered on demand
  libnvdimm: register nvdimm_bus devices with an nd_bus driver
  pmem: clarify a debug print in pmem_clear_poison
  x86/insn: remove pcommit
  Revert "KVM: x86: add pcommit support"
  nfit, tools/testing/nvdimm/: unify shutdown paths
  libnvdimm: move ->module to struct nvdimm_bus_descriptor
  nfit: cleanup acpi_nfit_init calling convention
  nfit: fix _FIT evaluation memory leak + use after free
  tools/testing/nvdimm: add manufacturing_{date|location} dimm properties
  tools/testing/nvdimm: add virtual ramdisk range
  acpi, nfit: treat virtual ramdisk SPA as pmem region
  pmem: kill __pmem address space
  pmem: kill wmb_pmem()
  libnvdimm, pmem: use nvdimm_flush() for namespace I/O writes
  fs/dax: remove wmb_pmem()
  libnvdimm, pmem: flush posted-write queues on shutdown
  ...
2016-07-28 17:38:16 -07:00
Dan Williams
0606263f24 Merge branch 'for-4.8/libnvdimm' into libnvdimm-for-next 2016-07-24 08:05:44 -07:00
Dan Williams
dfa169bbee Revert "KVM: x86: add pcommit support"
This reverts commit 8b3e34e46a.

Given the deprecation of the pcommit instruction, the relevant VMX
features and CPUID bits are not going to be rolled into the SDM.  Remove
their usage from KVM.

Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-23 11:04:23 -07:00
Cao, Lei
b244c9fc25 KVM: VMX: handle PML full VMEXIT that occurs during event delivery
With PML enabled, guest will shut down if a PML full VMEXIT occurs during
event delivery. According to Intel SDM 27.2.3, PML full VMEXIT can occur when
event is being delivered through IDT, so KVM should not exit to user space
with error. Instead, it should let EXIT_REASON_PML_FULL go through and the
event will be re-injected on the next VMENTRY.

Signed-off-by: Lei Cao <lei.cao@stratus.com>
Cc: stable@vger.kernel.org
Fixes: 843e433057 ("KVM: VMX: Add PML support in VMX")
[Shortened the summary and Cc'd stable.]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2016-07-16 15:27:40 +02:00
Jim Mattson
2f1fe81123 KVM: nVMX: Fix memory corruption when using VMCS shadowing
When freeing the nested resources of a vcpu, there is an assumption that
the vcpu's vmcs01 is the current VMCS on the CPU that executes
nested_release_vmcs12(). If this assumption is violated, the vcpu's
vmcs01 may be made active on multiple CPUs at the same time, in
violation of Intel's specification. Moreover, since the vcpu's vmcs01 is
not VMCLEARed on every CPU on which it is active, it can linger in a
CPU's VMCS cache after it has been freed and potentially
repurposed. Subsequent eviction from the CPU's VMCS cache on a capacity
miss can result in memory corruption.

It is not sufficient for vmx_free_vcpu() to call vmx_load_vmcs01(). If
the vcpu in question was last loaded on a different CPU, it must be
migrated to the current CPU before calling vmx_load_vmcs01().

Signed-off-by: Jim Mattson <jmattson@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-14 19:11:20 +02:00
Peter Feiner
4e59516a12 kvm: vmx: ensure VMCS is current while enabling PML
Between loading the new VMCS and enabling PML, the CPU was unpinned.
If the vCPU thread were migrated to another CPU in the interim (e.g.,
due to preemption or sleeping alloc_page), then the VMWRITEs to enable
PML would target the wrong VMCS -- or no VMCS at all:

  [ 2087.266950] vmwrite error: reg 200e value 3fe1d52000 (err -506126336)
  [ 2087.267062] vmwrite error: reg 812 value 1ff (err 511)
  [ 2087.267125] vmwrite error: reg 401e value 12229c00 (err 304258048)

This patch ensures that the VMCS remains current while enabling PML by
doing the VMWRITEs while the CPU is pinned. Allocation of the PML buffer
is hoisted out of the critical section.

Signed-off-by: Peter Feiner <pfeiner@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-14 19:11:19 +02:00
Radim Krčmář
3713131345 KVM: x86: add KVM_CAP_X2APIC_API
KVM_CAP_X2APIC_API is a capability for features related to x2APIC
enablement.  KVM_X2APIC_API_32BIT_FORMAT feature can be enabled to
extend APIC ID in get/set ioctl and MSI addresses to 32 bits.
Both are needed to support x2APIC.

The feature has to be enableable and disabled by default, because
get/set ioctl shifted and truncated APIC ID to 8 bits by using a
non-standard protocol inspired by xAPIC and the change is not
backward-compatible.

Changes to MSI addresses follow the format used by interrupt remapping
unit.  The upper address word, that used to be 0, contains upper 24 bits
of the LAPIC address in its upper 24 bits.  Lower 8 bits are reserved as
0.  Using the upper address word is not backward-compatible either as we
didn't check that userspace zeroed the word.  Reserved bits are still
not explicitly checked, but non-zero data will affect LAPIC addresses,
which will cause a bug.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-14 09:03:57 +02:00
Radim Krčmář
c93de59dcd KVM: VMX: optimize APIC ID read with APICv
The register is in hardware-compatible format now, so there is not need
to intercept.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-14 09:03:55 +02:00
Bandan Das
02120c45b0 kvm: vmx: advertise support for ept execute only
MMU now knows about execute only mappings, so
advertise the feature to L1 hypervisors

Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-14 09:03:50 +02:00
Bandan Das
d95c55687e kvm: mmu: track read permission explicitly for shadow EPT page tables
To support execute only mappings on behalf of L1 hypervisors,
reuse ACC_USER_MASK to signify if the L1 hypervisor has the R bit
set.

For the nested EPT case, we assumed that the U bit was always set
since there was no equivalent in EPT page tables.  Strictly
speaking, this was not necessary because handle_ept_violation
never set PFERR_USER_MASK in the error code (uf=0 in the
parlance of update_permission_bitmask).  We now have to set
both U and UF correctly, respectively in FNAME(gpte_access)
and in handle_ept_violation.

Also in handle_ept_violation bit 3 of the exit qualification is
not enough to detect a present PTE; all three bits 3-5 have to
be checked.

Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-14 09:03:50 +02:00
Bandan Das
ffb128c89b kvm: mmu: don't set the present bit unconditionally
To support execute only mappings on behalf of L1
hypervisors, we need to teach set_spte() to honor all three of
L1's XWR bits.  As a start, add a new variable "shadow_present_mask"
that will be set for non-EPT shadow paging and clear for EPT.

Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-14 09:03:14 +02:00
Paolo Bonzini
8391ce447f KVM: VMX: introduce vm_{entry,exit}_control_reset_shadow
There is no reason to read the entry/exit control fields of the
VMCS and immediately write back the same value.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-11 10:07:49 +02:00
Paolo Bonzini
9314006db8 KVM: nVMX: keep preemption timer enabled during L2 execution
Because the vmcs12 preemption timer is emulated through a separate hrtimer,
we can keep on using the preemption timer in the vmcs02 to emulare L1's
TSC deadline timer.

However, the corresponding bit in the pin-based execution control field
must be kept consistent between vmcs01 and vmcs02.  On vmentry we copy
it into the vmcs02; on vmexit the preemption timer must be disabled in
the vmcs01 if a preemption timer vmexit happened while in guest mode.

The preemption timer value in the vmcs02 is set by vmx_vcpu_run, so it
need not be considered in prepare_vmcs02.

Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Cc: Haozhong Zhang <haozhong.zhang@intel.com>
Tested-by: Wanpeng Li <kernellwp@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-11 09:49:29 +02:00
Wanpeng Li
55123e3c86 KVM: nVMX: avoid incorrect preemption timer vmexit in nested guest
The preemption timer for nested VMX is emulated by hrtimer which is started on L2
entry, stopped on L2 exit and evaluated via the check_nested_events hook. However,
nested_vmx_exit_handled is always returning true for preemption timer vmexit.  Then,
the L1 preemption timer vmexit is captured and be treated as a L2 preemption
timer vmexit, causing NULL pointer dereferences or worse in the L1 guest's
vmexit handler:

    BUG: unable to handle kernel NULL pointer dereference at           (null)
    IP: [<          (null)>]           (null)
    PGD 0
    Oops: 0010 [#1] SMP
    Call Trace:
     ? kvm_lapic_expired_hv_timer+0x47/0x90 [kvm]
     handle_preemption_timer+0xe/0x20 [kvm_intel]
     vmx_handle_exit+0x169/0x15a0 [kvm_intel]
     ? kvm_arch_vcpu_ioctl_run+0xd5d/0x19d0 [kvm]
     kvm_arch_vcpu_ioctl_run+0xdee/0x19d0 [kvm]
     ? kvm_arch_vcpu_ioctl_run+0xd5d/0x19d0 [kvm]
     ? vcpu_load+0x1c/0x60 [kvm]
     ? kvm_arch_vcpu_load+0x57/0x260 [kvm]
     kvm_vcpu_ioctl+0x2d3/0x7c0 [kvm]
     do_vfs_ioctl+0x96/0x6a0
     ? __fget_light+0x2a/0x90
     SyS_ioctl+0x79/0x90
     do_syscall_64+0x68/0x180
     entry_SYSCALL64_slow_path+0x25/0x25
    Code:  Bad RIP value.
    RIP  [<          (null)>]           (null)
     RSP <ffff8800b5263c48>
    CR2: 0000000000000000
    ---[ end trace 9c70c48b1a2bc66e ]---

This can be reproduced readily by preemption timer enabled on L0 and disabled
on L1.

Return false since preemption timer vmexits must never be reflected to L2.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-11 09:49:26 +02:00
Paolo Bonzini
1c17c3e6bf KVM: VMX: reflect broken preemption timer in vmcs_config
Simplify cpu_has_vmx_preemption_timer.  This is consistent with the
rest of setup_vmcs_config and preparatory for the next patch.

Tested-by: Wanpeng Li <kernellwp@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-11 09:48:49 +02:00
Wei Yongjun
03f6a22a39 KVM: x86: Use ARRAY_SIZE instead of dividing sizeof array with sizeof an element
Use ARRAY_SIZE instead of dividing sizeof array with sizeof an element

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-05 14:41:45 +02:00
Paolo Bonzini
9175d2e97b KVM: vmx: fix underflow in TSC deadline calculation
If the TSC deadline timer is programmed really close to the deadline or
even in the past, the computation in vmx_set_hv_timer can underflow and
cause delta_tsc to be set to a huge value.  This generally results
in vmx_set_hv_timer returning -ERANGE, but we can fix it by limiting
delta_tsc to be positive or zero.

Reported-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-01 11:03:39 +02:00
Paolo Bonzini
f2485b3e0c KVM: x86: use guest_exit_irqoff
This gains a few clock cycles per vmexit.  On Intel there is no need
anymore to enable the interrupts in vmx_handle_external_intr, since
we are using the "acknowledge interrupt on exit" feature.  AMD
needs to do that, and must be careful to avoid the interrupt shadow.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-01 11:03:38 +02:00
Paolo Bonzini
91fa0f8e9e KVM: x86: always use "acknowledge interrupt on exit"
This is necessary to simplify handle_external_intr in the next patch.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-07-01 11:03:36 +02:00
Quentin Casasnovas
ff30ef40de KVM: nVMX: VMX instructions: fix segment checks when L1 is in long mode.
I couldn't get Xen to boot a L2 HVM when it was nested under KVM - it was
getting a GP(0) on a rather unspecial vmread from Xen:

     (XEN) ----[ Xen-4.7.0-rc  x86_64  debug=n  Not tainted ]----
     (XEN) CPU:    1
     (XEN) RIP:    e008:[<ffff82d0801e629e>] vmx_get_segment_register+0x14e/0x450
     (XEN) RFLAGS: 0000000000010202   CONTEXT: hypervisor (d1v0)
     (XEN) rax: ffff82d0801e6288   rbx: ffff83003ffbfb7c   rcx: fffffffffffab928
     (XEN) rdx: 0000000000000000   rsi: 0000000000000000   rdi: ffff83000bdd0000
     (XEN) rbp: ffff83000bdd0000   rsp: ffff83003ffbfab0   r8:  ffff830038813910
     (XEN) r9:  ffff83003faf3958   r10: 0000000a3b9f7640   r11: ffff83003f82d418
     (XEN) r12: 0000000000000000   r13: ffff83003ffbffff   r14: 0000000000004802
     (XEN) r15: 0000000000000008   cr0: 0000000080050033   cr4: 00000000001526e0
     (XEN) cr3: 000000003fc79000   cr2: 0000000000000000
     (XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: 0000   cs: e008
     (XEN) Xen code around <ffff82d0801e629e> (vmx_get_segment_register+0x14e/0x450):
     (XEN)  00 00 41 be 02 48 00 00 <44> 0f 78 74 24 08 0f 86 38 56 00 00 b8 08 68 00
     (XEN) Xen stack trace from rsp=ffff83003ffbfab0:

     ...

     (XEN) Xen call trace:
     (XEN)    [<ffff82d0801e629e>] vmx_get_segment_register+0x14e/0x450
     (XEN)    [<ffff82d0801f3695>] get_page_from_gfn_p2m+0x165/0x300
     (XEN)    [<ffff82d0801bfe32>] hvmemul_get_seg_reg+0x52/0x60
     (XEN)    [<ffff82d0801bfe93>] hvm_emulate_prepare+0x53/0x70
     (XEN)    [<ffff82d0801ccacb>] handle_mmio+0x2b/0xd0
     (XEN)    [<ffff82d0801be591>] emulate.c#_hvm_emulate_one+0x111/0x2c0
     (XEN)    [<ffff82d0801cd6a4>] handle_hvm_io_completion+0x274/0x2a0
     (XEN)    [<ffff82d0801f334a>] __get_gfn_type_access+0xfa/0x270
     (XEN)    [<ffff82d08012f3bb>] timer.c#add_entry+0x4b/0xb0
     (XEN)    [<ffff82d08012f80c>] timer.c#remove_entry+0x7c/0x90
     (XEN)    [<ffff82d0801c8433>] hvm_do_resume+0x23/0x140
     (XEN)    [<ffff82d0801e4fe7>] vmx_do_resume+0xa7/0x140
     (XEN)    [<ffff82d080164aeb>] context_switch+0x13b/0xe40
     (XEN)    [<ffff82d080128e6e>] schedule.c#schedule+0x22e/0x570
     (XEN)    [<ffff82d08012c0cc>] softirq.c#__do_softirq+0x5c/0x90
     (XEN)    [<ffff82d0801602c5>] domain.c#idle_loop+0x25/0x50
     (XEN)
     (XEN)
     (XEN) ****************************************
     (XEN) Panic on CPU 1:
     (XEN) GENERAL PROTECTION FAULT
     (XEN) [error_code=0000]
     (XEN) ****************************************

Tracing my host KVM showed it was the one injecting the GP(0) when
emulating the VMREAD and checking the destination segment permissions in
get_vmx_mem_address():

     3)               |    vmx_handle_exit() {
     3)               |      handle_vmread() {
     3)               |        nested_vmx_check_permission() {
     3)               |          vmx_get_segment() {
     3)   0.074 us    |            vmx_read_guest_seg_base();
     3)   0.065 us    |            vmx_read_guest_seg_selector();
     3)   0.066 us    |            vmx_read_guest_seg_ar();
     3)   1.636 us    |          }
     3)   0.058 us    |          vmx_get_rflags();
     3)   0.062 us    |          vmx_read_guest_seg_ar();
     3)   3.469 us    |        }
     3)               |        vmx_get_cs_db_l_bits() {
     3)   0.058 us    |          vmx_read_guest_seg_ar();
     3)   0.662 us    |        }
     3)               |        get_vmx_mem_address() {
     3)   0.068 us    |          vmx_cache_reg();
     3)               |          vmx_get_segment() {
     3)   0.074 us    |            vmx_read_guest_seg_base();
     3)   0.068 us    |            vmx_read_guest_seg_selector();
     3)   0.071 us    |            vmx_read_guest_seg_ar();
     3)   1.756 us    |          }
     3)               |          kvm_queue_exception_e() {
     3)   0.066 us    |            kvm_multiple_exception();
     3)   0.684 us    |          }
     3)   4.085 us    |        }
     3)   9.833 us    |      }
     3) + 10.366 us   |    }

Cross-checking the KVM/VMX VMREAD emulation code with the Intel Software
Developper Manual Volume 3C - "VMREAD - Read Field from Virtual-Machine
Control Structure", I found that we're enforcing that the destination
operand is NOT located in a read-only data segment or any code segment when
the L1 is in long mode - BUT that check should only happen when it is in
protected mode.

Shuffling the code a bit to make our emulation follow the specification
allows me to boot a Xen dom0 in a nested KVM and start HVM L2 guests
without problems.

Fixes: f9eb4af67c ("KVM: nVMX: VMX instructions: add checks for #GP/#SS exceptions")
Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Eugene Korenevsky <ekorenevsky@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-27 15:30:44 +02:00
Ashok Raj
c45dcc71b7 KVM: VMX: enable guest access to LMCE related MSRs
On Intel platforms, this patch adds LMCE to KVM MCE supported
capabilities and handles guest access to LMCE related MSRs.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
[Haozhong: macro KVM_MCE_CAP_SUPPORTED => variable kvm_mce_cap_supported
           Only enable LMCE on Intel platform
           Check MSR_IA32_FEATURE_CONTROL when handling guest
             access to MSR_IA32_MCG_EXT_CTL]
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-23 19:17:29 +02:00
Haozhong Zhang
37e4c997da KVM: VMX: validate individual bits of guest MSR_IA32_FEATURE_CONTROL
KVM currently does not check the value written to guest
MSR_IA32_FEATURE_CONTROL, though bits corresponding to disabled features
may be set. This patch makes KVM to validate individual bits written to
guest MSR_IA32_FEATURE_CONTROL according to enabled features.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-23 19:17:29 +02:00
Haozhong Zhang
3b84080b95 KVM: VMX: move msr_ia32_feature_control to vcpu_vmx
msr_ia32_feature_control will be used for LMCE and not depend only on
nested anymore, so move it from struct nested_vmx to struct vcpu_vmx.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-23 19:17:28 +02:00
Yunhong Jiang
64672c95ea kvm: vmx: hook preemption timer support
Hook the VMX preemption timer to the "hv timer" functionality added
by the previous patch.  This includes: checking if the feature is
supported, if the feature is broken on the CPU, the hooks to
setup/clean the VMX preemption timer, arming the timer on vmentry
and handling the vmexit.

A module parameter states if the VMX preemption timer should be
utilized.

Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
[Move hv_deadline_tsc to struct vcpu_vmx, use -1 as the "unset" value.
 Put all VMX bits here.  Enable it by default #yolo. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 10:07:50 +02:00
Yunhong Jiang
bc22512bb2 kvm: vmx: rename vmx_pre/post_block to pi_pre/post_block
Prepare to switch from preemption timer to hrtimer in the
vmx_pre/post_block. Current functions are only for posted interrupt,
rename them accordingly.

Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 10:07:49 +02:00
Yang Zhang
a005219162 kvm: vmx: check apicv is active before using VT-d posted interrupt
VT-d posted interrupt is relying on the CPU side's posted interrupt.
Need to check whether VCPU's APICv is active before enabing VT-d
posted interrupt.

Fixes: d62caabb41
Cc: stable@vger.kernel.org
Signed-off-by: Yang Zhang <yang.zhang.wz@gmail.com>
Signed-off-by: Shengge Ding <shengge.dsg@alibaba-inc.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-06-16 09:38:24 +02:00