Re: [PATCH 4/6] Implement Hyper-V MSRs

[Avi Kivity <avi@redhat.com>]

Alexander Graf wrote:
> Hyper-V uses some MSRs, some of which are actually reserved for BIOS usage.
>
> But let's be nice today and have it its way, because otherwise it fails
> terribly.
>
> For MSRs where I could find a name I used the name, otherwise they're just
> added in their hex form for now.
>
>   

Most of these are not Hyper-V MSRs.  They are x86 MSRs that happen to be 
hit by Hyper-v.

> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index ef43a18..30e6b43 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -1932,6 +1932,7 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data)
>  		*data = svm->hsave_msr;
>  		break;
>  	case MSR_VM_CR:
> +	case 0x40000081:
>  		*data = 0;
>  		break;
>   

This probably is a Hyper-V MSR, but I don't see how it expects it to be 
present in real hardware.  Are you sure this is really needed?

> @@ -2034,6 +2035,10 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
>  	case MSR_VM_HSAVE_PA:
>  		svm->hsave_msr = data;
>  		break;
> +	case MSR_VM_CR:
> +	case MSR_VM_IGNNE:
> +	case MSR_K8_HWCR:
> +		break;
>   

Please add a ratelimited printk() if any value is written which would 
cause behaviour which we do not emulate.  This will prevent a guest 
getting unexpected behaviour silently.

-- 
error compiling committee.c: too many arguments to function