Re: [PATCH v7 2/2] x86 KVM:SVM: Provide "nosnp" boot option for sev kernel command line

[Borislav Petkov <bp@xxxxxxxxx>]

On Mon, Oct 14, 2024 at 08:09:48AM -0500, Pavan Kumar Paluri wrote:
> @@ -25,6 +26,12 @@ static int __init init_sev_config(char *str)
>  			continue;
>  		}
>  
> +		if (!strcmp(s, "nosnp")) {
> +			setup_clear_cpu_cap(X86_FEATURE_SEV_SNP);
> +			cc_platform_clear(CC_ATTR_HOST_SEV_SNP);
> +			continue;
> +		}

Well, if it is a HV-only option, then it better be such:

@@ -25,6 +26,17 @@ static int __init init_sev_config(char *str)
 			continue;
 		}
 
+		if (!strcmp(s, "nosnp")) {
+			if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR)) {
+				setup_clear_cpu_cap(X86_FEATURE_SEV_SNP);
+				cc_platform_clear(CC_ATTR_HOST_SEV_SNP);
+				continue;
+			} else {
+				goto warn;
+			}
+		}
+
+warn:
 		pr_info("SEV command-line option '%s' was not recognized\n", s);
 	}
 

-- 
Regards/Gruss,
    Boris.

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