Re: [PATCH] KVM: nVMX: set rflags to specify success in handle_invvpid() default case

From: linmiaohe
Date: Thu Jan 23 2020 - 04:36:35 EST


Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> On 23/01/20 09:55, Vitaly Kuznetsov wrote:
> > Your patch seems to do the right thing, however, I started wondering
> > if
> > WARN_ON_ONCE() is the right thing to do. SDM says that "If an
> > unsupported INVVPID type is specified, the instruction fails." and
> > this is similar to INVEPT and I decided to check what handle_invept()
> > does. Well, it does BUG_ON().
> >
> > Are we doing the right thing in any of these cases?
>
> Yes, both INVEPT and INVVPID catch this earlier.
>
> For INVEPT:
>
> types = (vmx->nested.msrs.ept_caps >> VMX_EPT_EXTENT_SHIFT) & 6;
>
> if (type >= 32 || !(types & (1 << type)))
> return nested_vmx_failValid(vcpu,
> VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
>
>
>
> For INVVPID:
>
> types = (vmx->nested.msrs.vpid_caps &
> VMX_VPID_EXTENT_SUPPORTED_MASK) >> 8;
>
> if (type >= 32 || !(types & (1 << type)))
> return nested_vmx_failValid(vcpu,
> VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
>
> So I'm leaning towards not applying Miaohe's patch. Happy Mouse Year to everyone, here is an ASCII art (except for one Unicode character) mouse:
>
>
> __()()
> / o)
> ~~~~\_,__,_>Â
>
> Thanks,

Yes, it seems my patch is meaningless. And thanks for both of your review and reply.
Happy Mouse Year and I catch a mickey mouse:

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Thanks both again.