Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe

From	Borislav Petkov <bp@alien8.de>
Newsgroups	linux.kernel
Subject	Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe
Date	2016-06-15 19:10 +0200
Message-ID	<rKmue-5m4-17@gated-at.bofh.it> (permalink)
References	<rKjZo-3Eh-29@gated-at.bofh.it> <rKjZo-3Eh-27@gated-at.bofh.it> <rKksq-3QZ-35@gated-at.bofh.it>
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On Wed, Jun 15, 2016 at 11:51:50AM -0300, Eduardo Habkost wrote:
> We have that: it is "-feature" (or "feature=off"). Features that
> can't be configured in the command-line should never appear to
> the guest unless you use "-cpu host,migratable=off".
> 
> Something that allows disabling feature flags that still don't
> have a name in QEMU would be useful for "-cpu
> host,migratable=off" only (and that's an interesting suggestion).
> But that's not the case here, I guess.

Right, and I'm wondering whether something like that would be useful for
testing purposes. For example, I want to enable a CPUID feature on the
command line and see how the kernel I'm booting in the guest reacts. And
that feature bit is not necessarily known to qemu/kvm.

Can we, say, pass whole CPUID leafs to qemu to report to the guest?
I.e., something like:

 ... -cpuid=0x5,eax=0x40,ebx=0xdeadbeef,ecx=0xcaffee ...

and so on.

Would that be interesting to add to qemu? I'd find something like that
very useful for testing kernels...

Thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.

Thread

Re: [x86] 5ac0c41bf3:  WARNING: CPU: 0 PID: 0 at  arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe Borislav Petkov <bp@alien8.de> - 2016-06-15 16:30 +0200
  Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at  arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe Paolo Bonzini <pbonzini@redhat.com> - 2016-06-15 17:00 +0200
  Re: [x86] 5ac0c41bf3:  WARNING: CPU: 0 PID: 0 at  arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe Eduardo Habkost <ehabkost@redhat.com> - 2016-06-15 17:00 +0200
    Re: [x86] 5ac0c41bf3:  WARNING: CPU: 0 PID: 0 at  arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe Borislav Petkov <bp@alien8.de> - 2016-06-15 19:10 +0200
  Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50  ex_handler_rdmsr_unsafe Andy Lutomirski <luto@amacapital.net> - 2016-06-15 19:40 +0200
    Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50  ex_handler_rdmsr_unsafe Andy Lutomirski <luto@amacapital.net> - 2016-06-15 20:00 +0200
      Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at  arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe Borislav Petkov <bp@alien8.de> - 2016-06-15 20:10 +0200
        Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50  ex_handler_rdmsr_unsafe Andy Lutomirski <luto@amacapital.net> - 2016-06-15 20:20 +0200
          Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at  arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe Borislav Petkov <bp@alien8.de> - 2016-06-15 20:30 +0200
            Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50  ex_handler_rdmsr_unsafe Andy Lutomirski <luto@amacapital.net> - 2016-06-15 20:50 +0200
    Re: [x86] 5ac0c41bf3: WARNING: CPU: 0 PID: 0 at  arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe Borislav Petkov <bp@alien8.de> - 2016-06-15 20:00 +0200

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