Re: [PATCH 8/9] allow read access to MSR_VM_VR

[Anthony Liguori <anthony@codemonkey.ws>]

Alexander Graf wrote:
> From: Joerg Roedel <joerg.roedel@amd.com>
>
> KVM tries to read the VM_CR MSR to find out if SVM was disabled by
> the BIOS. So implement read support for this MSR to make nested
> SVM running.
>
> Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
> Signed-off-by: Alexander Graf <agraf@suse.de>
> ---
>  arch/x86/kvm/svm.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 720b610..4582699 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -1869,6 +1869,9 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data)
>  	case MSR_VM_HSAVE_PA:
>  		*data = 0;
>  		break;
> +	case MSR_VM_CR:
> +		*data = 0;
> +		break;
>   

It would be useful to support setting this value too.  Then we could 
disable SVM support by writing the MSR in the BIOS.

Regards,

Anthony Liguori

>  	default:
>  		return kvm_get_msr_common(vcpu, ecx, data);
>  	}
>