Commit Graph

13878 Commits

Author SHA1 Message Date
Avi Kivity
0fe5912884 KVM: x86 emulator: switch src decode to decode_operand()
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:54 +03:00
Avi Kivity
5217973ef8 KVM: x86 emulator: qualify OpReg inhibit_byte_regs hack
OpReg decoding has a hack that inhibits byte registers for movsx and movzx
instructions.  It should be replaced by something better, but meanwhile,
qualify that the hack is only active for the destination operand.

Note these instructions only use OpReg for the destination, but better to
be explicit about it.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:53 +03:00
Avi Kivity
608aabe316 KVM: x86 emulator: switch OpImmUByte decode to decode_imm()
Similar to SrcImmUByte.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:52 +03:00
Avi Kivity
20c29ff205 KVM: x86 emulator: free up some flag bits near src, dst
Op fields are going to grow by a bit, we need two free bits.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:51 +03:00
Avi Kivity
4dd6a57df7 KVM: x86 emulator: switch src2 to generic decode_operand()
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:50 +03:00
Avi Kivity
b1ea50b2b6 KVM: x86 emulator: expand decode flags to 64 bits
Unifiying the operands means not taking advantage of the fact that some
operand types can only go into certain operands (for example, DI can only
be used by the destination), so we need more bits to hold the operand type.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:49 +03:00
Avi Kivity
a99455499a KVM: x86 emulator: split dst decode to a generic decode_operand()
Instead of decoding each operand using its own code, use a generic
function.  Start with the destination operand.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:48 +03:00
Avi Kivity
f09ed83e21 KVM: x86 emulator: move memop, memopp into emulation context
Simplifies further generalization of decode.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:47 +03:00
Avi Kivity
3329ece161 KVM: x86 emulator: convert group 3 instructions to direct decode
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:46 +03:00
Jan Kiszka
9bc5791d4a KVM: x86: Add module parameter for lapic periodic timer limit
Certain guests, specifically RTOSes, request faster periodic timers than
what we allow by default. Add a module parameter to adjust the limit for
non-standard setups. Also add a rate-limited warning in case the guest
requested more.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:44 +03:00
Jan Kiszka
bd80158aff KVM: Clean up and extend rate-limited output
The use of printk_ratelimit is discouraged, replace it with
pr*_ratelimited or __ratelimit. While at it, convert remaining
guest-triggerable printks to rate-limited variants.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:43 +03:00
Jan Kiszka
7712de872c KVM: x86: Avoid guest-triggerable printks in APIC model
Convert remaining printks that the guest can trigger to apic_printk.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:42 +03:00
Jan Kiszka
1e2b1dd797 KVM: x86: Move kvm_trace_exit into atomic vmexit section
This avoids that events causing the vmexit are recorded before the
actual exit reason.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:41 +03:00
Avi Kivity
caa8a168e3 KVM: x86 emulator: disable writeback for TEST
The TEST instruction doesn't write its destination operand.  This
could cause problems if an MMIO register was accessed using the TEST
instruction.  Recently Windows XP was observed to use TEST against
the APIC ICR; this can cause spurious IPIs.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:40 +03:00
Avi Kivity
e8f2b1d621 KVM: x86 emulator: simplify emulate_1op_rax_rdx()
emulate_1op_rax_rdx() is always called with the same parameters.  Simplify
by passing just the emulation context.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:37 +03:00
Avi Kivity
9fef72ce10 KVM: x86 emulator: merge the two emulate_1op_rax_rdx implementations
We have two emulate-with-extended-accumulator implementations: once
which expect traps (_ex) and one which doesn't (plain).  Drop the
plain implementation and always use the one which expects traps;
it will simply return 0 in the _ex argument and we can happily ignore
it.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:36 +03:00
Avi Kivity
d1eef45d59 KVM: x86 emulator: simplify emulate_1op()
emulate_1op() is always called with the same parameters.  Simplify
by passing just the emulation context.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:35 +03:00
Avi Kivity
29053a60d7 KVM: x86 emulator: simplify emulate_2op_cl()
emulate_2op_cl() is always called with the same parameters.  Simplify
by passing just the emulation context.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:34 +03:00
Avi Kivity
761441b9f4 KVM: x86 emulator: simplify emulate_2op_cl()
emulate_2op_cl() is always called with the same parameters.  Simplify
by passing just the emulation context.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:33 +03:00
Avi Kivity
a31b9ceadb KVM: x86 emulator: simplify emulate_2op_SrcV()
emulate_2op_SrcV(), and its siblings, emulate_2op_SrcV_nobyte()
and emulate_2op_SrcB(), all use the same calling conventions
and all get passed exactly the same parameters.  Simplify them
by passing just the emulation context.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:52:32 +03:00
Kevin Tian
58fbbf26eb KVM: APIC: avoid instruction emulation for EOI writes
Instruction emulation for EOI writes can be skipped, since sane
guest simply uses MOV instead of string operations. This is a nice
improvement when guest doesn't support x2apic or hyper-V EOI
support.

a single VM bandwidth is observed with ~8% bandwidth improvement
(7.4Gbps->8Gbps), by saving ~5% cycles from EOI emulation.

Signed-off-by: Kevin Tian <kevin.tian@intel.com>
<Based on earlier work from>:
Signed-off-by: Eddie Dong <eddie.dong@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:52:17 +03:00
Nadav Har'El
45133ecaae KVM: SVM: Fix TSC MSR read in nested SVM
When the TSC MSR is read by an L2 guest (when L1 allowed this MSR to be
read without exit), we need to return L2's notion of the TSC, not L1's.

The current code incorrectly returned L1 TSC, because svm_get_msr() was also
used in x86.c where this was assumed, but now that these places call the new
svm_read_l1_tsc(), the MSR read can be fixed.

Signed-off-by: Nadav Har'El <nyh@il.ibm.com>
Tested-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:18:03 +03:00
Nadav Har'El
27fc51b21c KVM: nVMX: Fix nested VMX TSC emulation
This patch fixes two corner cases in nested (L2) handling of TSC-related
issues:

1. Somewhat suprisingly, according to the Intel spec, if L1 allows WRMSR to
the TSC MSR without an exit, then this should set L1's TSC value itself - not
offset by vmcs12.TSC_OFFSET (like was wrongly done in the previous code).

2. Allow L1 to disable the TSC_OFFSETING control, and then correctly ignore
the vmcs12.TSC_OFFSET.

Signed-off-by: Nadav Har'El <nyh@il.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:18:02 +03:00
Nadav Har'El
d5c1785d2f KVM: L1 TSC handling
KVM assumed in several places that reading the TSC MSR returns the value for
L1. This is incorrect, because when L2 is running, the correct TSC read exit
emulation is to return L2's value.

We therefore add a new x86_ops function, read_l1_tsc, to use in places that
specifically need to read the L1 TSC, NOT the TSC of the current level of
guest.

Note that one change, of one line in kvm_arch_vcpu_load, is made redundant
by a different patch sent by Zachary Amsden (and not yet applied):
kvm_arch_vcpu_load() should not read the guest TSC, and if it didn't, of
course we didn't have to change the call of kvm_get_msr() to read_l1_tsc().

[avi: moved callback to kvm_x86_ops tsc block]

Signed-off-by: Nadav Har'El <nyh@il.ibm.com>
Acked-by: Zachary Amsdem <zamsden@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:18:02 +03:00
Yang, Wei Y
cd46868c7f KVM: MMU: Fix SMEP failure during fetch
This patch fix kvm-unit-tests hanging and incorrect PT_ACCESSED_MASK
bit set in the case of SMEP fault.  The code updated 'eperm' after
the variable was checked.

Signed-off-by: Yang, Wei <wei.y.yang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:18:02 +03:00
Avi Kivity
e4e517b4be KVM: MMU: Do not unconditionally read PDPTE from guest memory
Architecturally, PDPTEs are cached in the PDPTRs when CR3 is reloaded.
On SVM, it is not possible to implement this, but on VMX this is possible
and was indeed implemented until nested SVM changed this to unconditionally
read PDPTEs dynamically.  This has noticable impact when running PAE guests.

Fix by changing the MMU to read PDPTRs from the cache, falling back to
reading from memory for the nested MMU.

Signed-off-by: Avi Kivity <avi@redhat.com>
Tested-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:18:01 +03:00
Julia Lawall
cf3ace79c0 KVM: VMX: trivial: use BUG_ON
Use BUG_ON(x) rather than if(x) BUG();

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ identifier x; @@
-if (x) BUG();
+BUG_ON(x);

@@ identifier x; @@
-if (!x) BUG();
+BUG_ON(!x);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:18:01 +03:00
Marcelo Tosatti
742bc67042 KVM: x86: report valid microcode update ID
Windows Server 2008 SP2 checked build with smp > 1 BSOD's during
boot due to lack of microcode update:

*** Assertion failed: The system BIOS on this machine does not properly
support the processor.  The system BIOS did not load any microcode update.
A BIOS containing the latest microcode update is needed for system reliability.
(CurrentUpdateRevision != 0)
***   Source File: d:\longhorn\base\hals\update\intelupd\update.c, line 440

Report a non-zero microcode update signature to make it happy.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:18:01 +03:00
Takuya Yoshikawa
1d2887e2d8 KVM: x86 emulator: Make x86_decode_insn() return proper macros
Return EMULATION_OK/FAILED consistently.  Also treat instruction fetch
errors, not restricted to X86EMUL_UNHANDLEABLE, as EMULATION_FAILED;
although this cannot happen in practice, the current logic will continue
the emulation even if the decoder fails to fetch the instruction.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:18:01 +03:00
Takuya Yoshikawa
7d88bb4803 KVM: x86 emulator: Let compiler know insn_fetch() rarely fails
Fetching the instruction which was to be executed by the guest cannot
fail normally.  So compiler should always predict that it will succeed.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:18:00 +03:00
Takuya Yoshikawa
e85a10852c KVM: x86 emulator: Drop _size argument from insn_fetch()
_type is enough to know the size.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:59 +03:00
Takuya Yoshikawa
807941b121 KVM: x86 emulator: Use ctxt->_eip directly in do_insn_fetch_byte()
Instead of passing ctxt->_eip from insn_fetch() call sites, get it from
ctxt in do_insn_fetch_byte().  This is done by replacing the argument
_eip of insn_fetch() with _ctxt, which should be better than letting the
macro use ctxt silently in its body.

Though this changes the place where ctxt->_eip is incremented from
insn_fetch() to do_insn_fetch_byte(), this does not have any real
effect.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:59 +03:00
Sasha Levin
743eeb0b01 KVM: Intelligent device lookup on I/O bus
Currently the method of dealing with an IO operation on a bus (PIO/MMIO)
is to call the read or write callback for each device registered
on the bus until we find a device which handles it.

Since the number of devices on a bus can be significant due to ioeventfds
and coalesced MMIO zones, this leads to a lot of overhead on each IO
operation.

Instead of registering devices, we now register ranges which points to
a device. Lookup is done using an efficient bsearch instead of a linear
search.

Performance test was conducted by comparing exit count per second with
200 ioeventfds created on one byte and the guest is trying to access a
different byte continuously (triggering usermode exits).
Before the patch the guest has achieved 259k exits per second, after the
patch the guest does 274k exits per second.

Cc: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:59 +03:00
Stefan Hajnoczi
0d460ffc09 KVM: Use __print_symbolic() for vmexit tracepoints
The vmexit tracepoints format the exit_reason to make it human-readable.
Since the exit_reason depends on the instruction set (vmx or svm),
formatting is handled with ftrace_print_symbols_seq() by referring to
the appropriate exit reason table.

However, the ftrace_print_symbols_seq() function is not meant to be used
directly in tracepoints since it does not export the formatting table
which userspace tools like trace-cmd and perf use to format traces.

In practice perf dies when formatting vmexit-related events and
trace-cmd falls back to printing the numeric value (with extra
formatting code in the kvm plugin to paper over this limitation).  Other
userspace consumers of vmexit-related tracepoints would be in similar
trouble.

To avoid significant changes to the kvm_exit tracepoint, this patch
moves the vmx and svm exit reason tables into arch/x86/kvm/trace.h and
selects the right table with __print_symbolic() depending on the
instruction set.  Note that __print_symbolic() is designed for exporting
the formatting table to userspace and allows trace-cmd and perf to work.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:59 +03:00
Stefan Hajnoczi
e097e5ffd6 KVM: Record instruction set in all vmexit tracepoints
The kvm_exit tracepoint recently added the isa argument to aid decoding
exit_reason.  The semantics of exit_reason depend on the instruction set
(vmx or svm) and the isa argument allows traces to be analyzed on other
machines.

Add the isa argument to kvm_nested_vmexit and kvm_nested_vmexit_inject
so these tracepoints can also be self-describing.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:58 +03:00
Mike Waychison
d1613ad5d0 KVM: Really fix HV_X64_MSR_APIC_ASSIST_PAGE
Commit 0945d4b228 tried to fix the get_msr path for the
HV_X64_MSR_APIC_ASSIST_PAGE msr, but was poorly tested.  We should be
returning 0 if the read succeeded, and passing the value back to the
caller via the pdata out argument, not returning the value directly.

Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:58 +03:00
Mike Waychison
14fa67ee95 KVM: x86: get_msr support for HV_X64_MSR_APIC_ASSIST_PAGE
"get" support for the HV_X64_MSR_APIC_ASSIST_PAGE msr was missing, even
though it is explicitly enumerated as something the vmm should save in
msrs_to_save and reported to userland via the KVM_GET_MSR_INDEX_LIST
ioctl.

Add "get" support for HV_X64_MSR_APIC_ASSIST_PAGE.  We simply return the
guest visible value of this register, which seems to be correct as a set
on the register is validated for us already.

Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:17:58 +03:00
Sasha Levin
8c3ba334f8 KVM: x86: Raise the hard VCPU count limit
The patch raises the hard limit of VCPU count to 254.

This will allow developers to easily work on scalability
and will allow users to test high VCPU setups easily without
patching the kernel.

To prevent possible issues with current setups, KVM_CAP_NR_VCPUS
now returns the recommended VCPU limit (which is still 64) - this
should be a safe value for everybody, while a new KVM_CAP_MAX_VCPUS
returns the hard limit which is now 254.

Cc: Avi Kivity <avi@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Suggested-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:17:57 +03:00
Xiao Guangrong
22388a3c8c KVM: x86: cleanup the code of read/write emulation
Using the read/write operation to remove the same code

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:17 +03:00
Xiao Guangrong
77d197b2ca KVM: x86: abstract the operation for read/write emulation
The operations of read emulation and write emulation are very similar, so we
can abstract the operation of them, in larter patch, it is used to cleanup the
same code

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:17 +03:00
Xiao Guangrong
ca7d58f375 KVM: x86: fix broken read emulation spans a page boundary
If the range spans a page boundary, the mmio access can be broke, fix it as
write emulation.

And we already get the guest physical address, so use it to read guest data
directly to avoid walking guest page table again

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-09-25 19:17:17 +03:00
Avi Kivity
9be3be1f15 KVM: x86 emulator: fix Src2CL decode
Src2CL decode (used for double width shifts) erronously decodes only bit 3
of %rcx, instead of bits 7:0.

Fix by decoding %cl in its entirety.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:14:58 +03:00
Zhao Jin
41bc3186b3 KVM: MMU: fix incorrect return of spte
__update_clear_spte_slow should return original spte while the
current code returns low half of original spte combined with high
half of new spte.

Signed-off-by: Zhao Jin <cronozhj@gmail.com>
Reviewed-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-09-25 19:13:25 +03:00
Linus Torvalds
abbe0d3c26 Merge branch 'stable/bug.fixes' of git://oss.oracle.com/git/kwilk/xen
* 'stable/bug.fixes' of git://oss.oracle.com/git/kwilk/xen:
  xen/i386: follow-up to "replace order-based range checking of M2P table by linear one"
  xen/irq: Alter the locking to use a mutex instead of a spinlock.
  xen/e820: if there is no dom0_mem=, don't tweak extra_pages.
  xen: disable PV spinlocks on HVM
2011-09-16 11:28:11 -07:00
Linus Torvalds
a7f934d4f1 asm alternatives: remove incorrect alignment notes
On x86-64, they were just wasteful: with the explicitly added (now
unnecessary) padding, the size of the alternatives structure was 16
bytes, and an alignment of 8 bytes didn't hurt much.

However, it was still silly, since the natural size and alignment for
the structure is actually just 12 bytes, 4-byte aligned since commit
59e97e4d6f ("x86: Make alternative instruction pointers relative").
So removing the padding, and removing the extra alignment is just a good
idea.

On x86-32, the alignment of 4 bytes was correct, but was incorrectly
hardcoded as 8 bytes in <asm/alternative-asm.h>.  That header file had
used to be an x86-64 only header file, but various unification efforts
have made it be used for x86-32 too (ie the unification of rwlock and
rwsem).

That in turn caused x86-32 boot failures, because the extra alignment
would result in random zero-filled words in the altinstructions section,
causing oopses early at boot when doing alternative instruction
replacement.

So just remove all the alignment noise entirely.  It's wrong, and it's
unnecessary.  The section itself is already properly aligned by the
linker scripts, and all additions to the section had better be of the
proper 12-byte format, keeping it aligned.  So if the align directive
were to ever make a difference, that would be an indication of a serious
bug to begin with.

Reported-by: Werner Landgraf <w.landgraf@ru.r>
Acked-by: Andrew Lutomirski <luto@mit.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-09-15 13:28:33 -07:00
Jan Beulich
61cca2fab7 xen/i386: follow-up to "replace order-based range checking of M2P table by linear one"
The numbers obtained from the hypervisor really can't ever lead to an
overflow here, only the original calculation going through the order
of the range could have. This avoids the (as Jeremy points outs)
somewhat ugly NULL-based calculation here.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-09-15 04:39:46 -04:00
David Vrabel
e3b73c4a25 xen/e820: if there is no dom0_mem=, don't tweak extra_pages.
The patch "xen: use maximum reservation to limit amount of usable RAM"
(d312ae878b) breaks machines that
do not use 'dom0_mem=' argument with:

reserve RAM buffer: 000000133f2e2000 - 000000133fffffff
(XEN) mm.c:4976:d0 Global bit is set to kernel page fffff8117e
(XEN) domain_crash_sync called from entry.S
(XEN) Domain 0 (vcpu#0) crashed on cpu#0:
...

The reason being that the last E820 entry is created using the
'extra_pages' (which is based on how many pages have been freed).
The mentioned git commit sets the initial value of 'extra_pages'
using a hypercall which returns the number of pages (if dom0_mem
has been used) or -1 otherwise. If the later we return with
MAX_DOMAIN_PAGES as basis for calculation:

    return min(max_pages, MAX_DOMAIN_PAGES);

and use it:

     extra_limit = xen_get_max_pages();
     if (extra_limit >= max_pfn)
             extra_pages = extra_limit - max_pfn;
     else
             extra_pages = 0;

which means we end up with extra_pages = 128GB in PFNs (33554432)
- 8GB in PFNs (2097152, on this specific box, can be larger or smaller),
and then we add that value to the E820 making it:

  Xen: 00000000ff000000 - 0000000100000000 (reserved)
  Xen: 0000000100000000 - 000000133f2e2000 (usable)

which is clearly wrong. It should look as so:

  Xen: 00000000ff000000 - 0000000100000000 (reserved)
  Xen: 0000000100000000 - 000000027fbda000 (usable)

Naturally this problem does not present itself if dom0_mem=max:X
is used.

CC: stable@kernel.org
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-09-13 10:17:32 -04:00
Linus Torvalds
d9543314ee Merge branch 'upstream/bugfix' of git://github.com/jsgf/linux-xen
* 'upstream/bugfix' of git://github.com/jsgf/linux-xen:
  xen: use non-tracing preempt in xen_clocksource_read()
2011-09-12 17:22:31 -07:00
Shyam Iyer
5307f6d5fb Fix pointer dereference before call to pcie_bus_configure_settings
Commit b03e7495a8 ("PCI: Set PCI-E Max Payload Size on fabric")
introduced a potential NULL pointer dereference in calls to
pcie_bus_configure_settings due to attempts to access pci_bus self
variables when the self pointer is NULL.

To correct this, verify that the self pointer in pci_bus is non-NULL
before dereferencing it.

Reported-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Shyam Iyer <shyam_iyer@dell.com>
Signed-off-by: Jon Mason <mason@myri.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-09-09 19:49:58 -07:00
Stefano Stabellini
f10cd522c5 xen: disable PV spinlocks on HVM
PV spinlocks cannot possibly work with the current code because they are
enabled after pvops patching has already been done, and because PV
spinlocks use a different data structure than native spinlocks so we
cannot switch between them dynamically. A spinlock that has been taken
once by the native code (__ticket_spin_lock) cannot be taken by
__xen_spin_lock even after it has been released.

Reported-and-Tested-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-09-08 13:59:06 -04:00