Re: [PATCH 13/20] KVM: x86 emulator: fix memory access during x86 emulation

Stefan Bader
2010-03-08T14:10:10Z

Avi Kivity wrote:
> On 03/06/2010 03:53 PM, Stefan Bader wrote:
>> i Avi,
>>
>> we currently try to integrate this patch for an update into a 2.6.32
>> based
>> system (amongst other kvm updates). But as soon as this patch gets
>> added kvm
>> will die on startup in kvm_leave_lazy_mmu. This has been documented here:
>>
>> https://bugs.edge.launchpad.net/ubuntu/+source/linux/+bug/531823
>>
>> I have placed the backports of your patches, which are currently in
>> linux-next
>> and marked for stable here:
>>
>> git://kernel.ubuntu.com/smb/linux-2.6.32.y kvm
>>
>> I have tested the failure with a version that got only the following
>> patches in:
>> KVM: x86 emulator: Add Virtual-8086 mode of emulation
>> KVM: x86 emulator: fix memory access during x86 emulation
>> KVM: x86 emulator: Check IOPL level during io instruction emulation
>> KVM: x86 emulator: Fix popf emulation
>> KVM: x86 emulator: Check CPL level during privilege instruction emulation
>>
>> and also with a version that takes all stable patches up to the bad one:
>> KVM: VMX: Trap and invalid MWAIT/MONITOR instruction
>> KVM: x86 emulator: Add group8 instruction decoding
>> KVM: x86 emulator: Add group9 instruction decoding
>> KVM: x86 emulator: Add Virtual-8086 mode of emulation
>> KVM: x86 emulator: fix memory access during x86 emulation
>>
>> But as soon as the fix for memory access gets added, the bug will
>> occur. Would
>> you have an idea what might be causing this?
>>
>
> Does the same guest, using the same qemu-kvm, work on kvm.git or upstream?
>
The test was done with a kvm user-space package based on 0.12.3 (which seems to
be the current upstream version). I try to do a test on the git version.

Stefan