Re: [PATCH 3/7 v7] KVM: nSVM: No need to set bits 11:0 in MSRPM and IOPM bitmaps

[Paolo Bonzini <pbonzini@redhat.com>]

On 12/04/21 23:56, Krish Sadhukhan wrote:
> According to APM vol 2, hardware ignores the low 12 bits in MSRPM and IOPM
> bitmaps. Therefore setting/unssetting these bits has no effect as far as
> VMRUN is concerned. Also, setting/unsetting these bits prevents tests from
> verifying hardware behavior.

Tests should only verify KVM behavior, in order to verify hardware 
behavior you have to run them on bare metal.

Still, the patch is okay.

Paolo

> 
> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> ---
>   arch/x86/kvm/svm/nested.c | 2 --
>   1 file changed, 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index ae53ae46ebca..fd42c8b7f99a 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -287,8 +287,6 @@ static void nested_load_control_from_vmcb12(struct vcpu_svm *svm,
>   
>   	/* Copy it here because nested_svm_check_controls will check it.  */
>   	svm->nested.ctl.asid           = control->asid;
> -	svm->nested.ctl.msrpm_base_pa &= ~0x0fffULL;
> -	svm->nested.ctl.iopm_base_pa  &= ~0x0fffULL;
>   }
>   
>   /*
>