Re: [PATCH 0/2] KVM guest-kernel panics double fault

["Stephan Bärwolf" <stephan.baerwolf@tu-ilmenau.de>]

Thank you for applying this, Marcelo.

I fear we (or me after I agreed) did some mistake by erasing the additional
cpuid 0x80000001 checks.
In contradiction to only AMD it MUST also apply on Intel-CPUs.

Documentation
"http://www.intel.com/content/dam/doc/manual/64-ia-32-architectures-software-developer-manual-325462.pdf"
Vol. 2A 3-207 (PDF-page 811) first block of table.
(in addition AMD's doku "http://support.amd.com/us/Processor_TechDocs/APM_V3_24594.pdf"
page 376 (PDF-page 408) table "Exceptions" on the bottom)

Not all CPUs might have a syscall op at all (even in longmode) - they informing about that
via cpuid (But MSR_EFER may be still set).
(You can force it externally in qemu-kvm-emulation via "-cpu host,-syscall" ...)
So an (guest) operating-system might not install *STAR-registers and crash again on such vcpus, right?

I'll prepare some patch, asap. So everybody can judge this...

regards, Stephan

On 01/13/12 11:13, Marcelo Tosatti wrote:
> On Thu, Jan 12, 2012 at 04:56:33PM +0100, Jan Kiszka wrote:
>>> Stephan Baerwolf (2):
>>>   KVM: extend "struct x86_emulate_ops" with "get_cpuid"
>>>   KVM: fix missing "illegal instruction"-trap in protected modes
>>>
>>>  arch/x86/include/asm/kvm_emulate.h |   19 ++++++++
>>>  arch/x86/kvm/emulate.c             |   80
>>> ++++++++++++++++++++++++++++++++++-
>>>  arch/x86/kvm/x86.c                 |   21 +++++++++
>>>  3 files changed, 117 insertions(+), 3 deletions(-)
>>>
>> linux/scripts/checkpatch.pl can help identifying remaining style violations.
>>
>> Moreover, when sending your patches via Thunderbird, you first need to
>> make sure that you have its line wrapping under control. "Toggle Word
>> Wrap" helps me for single patches. But for series, I prefer (scripted)
>> git format-patch/send-email.
> Applied a cleanup up version of these patches. Thanks Stephan.
>
> http://git.kernel.org/?p=virt/kvm/kvm.git;a=commit;h=0769c5de24621141c953fbe1f943582d37cb4244
>
> http://git.kernel.org/?p=virt/kvm/kvm.git;a=commit;h=e28ba7bb020f07193bc000453c8775e9d2c0dda7
>
>
>


-- 
Dipl.-Inf. Stephan Bärwolf
Ilmenau University of Technology, Integrated Communication Systems Group
Phone: +49 (0)3677 69 4130
Email: stephan.baerwolf@tu-ilmenau.de,  
Web: http://www.tu-ilmenau.de/iks