Re: [PATCH v3 2/3] KVM: SEV-ES: Disallow SEV-ES guests when X86_FEATURE_LBRV is absent

[Paolo Bonzini]

On 5/23/24 14:18, Ravi Bangoria wrote:
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 489b0183f37d..dcb5eb00a4f5 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -5308,11 +5308,17 @@ static __init int svm_hardware_setup(void)
>   
>   	nrips = nrips && boot_cpu_has(X86_FEATURE_NRIPS);
>   
> +	if (lbrv) {
> +		if (!boot_cpu_has(X86_FEATURE_LBRV))
> +			lbrv = false;
> +		else
> +			pr_info("LBR virtualization supported\n");
> +	}
>   	/*
>   	 * Note, SEV setup consumes npt_enabled and enable_mmio_caching (which
>   	 * may be modified by svm_adjust_mmio_mask()), as well as nrips.
>   	 */

Since it consumes nrips, just make lbrv non-static:

/* enable/disable Next RIP Save */
int nrips = true;
module_param(nrips, int, 0444);

Paolo