Re: [PATCH v2 1/3] KVM: x86: Exit to user-mode on #UD intercept when emulator requires

[Liran Alon <LIRAN.ALON@ORACLE.COM>]

On 07/11/17 14:22, Paolo Bonzini wrote:
> On 07/11/2017 09:12, Liran Alon wrote:
>>
>>
>> On 07/11/17 02:47, Wanpeng Li wrote:
>>> 2017-11-06 22:39 GMT+08:00 Liran Alon <liran.alon@oracle.com>:
>>>> Signed-off-by: Liran Alon <liran.alon@oracle.com>
>>>> Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
>>>> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>>>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>>>> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
>>>> Cc: stable@vger.kernel.org
>>>
>>> Except the changelog.
>> Thanks for the review.
>> Currently both you and Paolo added "Reviewed-by" to this commit.
>>
>> Is there anything else you wish me to add to the commit message before
>> this commit being accepted? Do you have a suggestion? I though the
>> commit-title explains it enough for this trivial patch and didn't saw
>> any complain about not having body by ./scripts/checkpatch.pl.
>>
>> In addition, if I would need to edit commit message body, should I send
>> the next version of this commit as a standalone or re-send the entire
>> series?
>
> No, don't worry.  Generally, when a maintainer adds a Reviewed-by it
> means that it's just a matter of time before the patch goes in.
>
> For the commit message, I was thinking of something like:
>
> ---
> Instruction emulation after trapping a #UD exception can result in an
> MMIO access, for example when emulating a MOVBE on a processor that
> doesn't support the instruction.  In this case, the #UD vmexit handler
> must exit to user mode, but there wasn't any code to do so.  Add it for
> both VMX and SVM.
> ---
>
> Sounds good?
Sounds good. Thanks.
So if I understood correctly, I leave it to you to insert the patch with 
this commit message when it is inserted.

Thanks. :)
>
> Paolo
>
>> Thanks,
>> -Liran
>>
>>>
>>> Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
>>>
>>>> ---
>>>>    arch/x86/kvm/svm.c | 2 ++
>>>>    arch/x86/kvm/vmx.c | 2 ++
>>>>    2 files changed, 4 insertions(+)
>>>>
>>>> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
>>>> index 0e68f0b3cbf7..e0162b20e3c9 100644
>>>> --- a/arch/x86/kvm/svm.c
>>>> +++ b/arch/x86/kvm/svm.c
>>>> @@ -2189,6 +2189,8 @@ static int ud_interception(struct vcpu_svm *svm)
>>>>           int er;
>>>>
>>>>           er = emulate_instruction(&svm->vcpu, EMULTYPE_TRAP_UD);
>>>> +       if (er == EMULATE_USER_EXIT)
>>>> +               return 0;
>>>>           if (er != EMULATE_DONE)
>>>>                   kvm_queue_exception(&svm->vcpu, UD_VECTOR);
>>>>           return 1;
>>>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>>>> index 95a01609d7ee..2b63d9edc207 100644
>>>> --- a/arch/x86/kvm/vmx.c
>>>> +++ b/arch/x86/kvm/vmx.c
>>>> @@ -5886,6 +5886,8 @@ static int handle_exception(struct kvm_vcpu *vcpu)
>>>>                           return 1;
>>>>                   }
>>>>                   er = emulate_instruction(vcpu, EMULTYPE_TRAP_UD);
>>>> +               if (er == EMULATE_USER_EXIT)
>>>> +                       return 0;
>>>>                   if (er != EMULATE_DONE)
>>>>                           kvm_queue_exception(vcpu, UD_VECTOR);
>>>>                   return 1;
>>>> --
>>>> 1.9.1
>>>>
>