From: Paolo Bonzini Date: Tue, 4 Feb 2025 16:13:24 +0000 (-0500) Subject: kvm: x86: SRSO_USER_KERNEL_NO is not synthesized X-Git-Tag: v6.14-rc2~3^2~5 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ee3a66f431d689b796b9cb48aefd3d223540381c;p=thirdparty%2Flinux.git kvm: x86: SRSO_USER_KERNEL_NO is not synthesized SYNTHESIZED_F() generally is used together with setup_force_cpu_cap(), i.e. when it makes sense to present the feature even if cpuid does not have it *and* the VM is not able to see the difference. For example, it can be used when mitigations on the host automatically protect the guest as well. The "SYNTHESIZED_F(SRSO_USER_KERNEL_NO)" line came in as a conflict resolution between the CPUID overhaul from the KVM tree and support for the feature in the x86 tree. Using it right now does not hurt, or make a difference for that matter, because there is no setup_force_cpu_cap(X86_FEATURE_SRSO_USER_KERNEL_NO). However, it is a little less future proof in case such a setup_force_cpu_cap() appears later, for a case where the kernel somehow is not vulnerable but the guest would have to apply the mitigation. Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 2cbb3874ad398..8eb3a88707f21 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -1180,7 +1180,7 @@ void kvm_set_cpu_caps(void) SYNTHESIZED_F(SBPB), SYNTHESIZED_F(IBPB_BRTYPE), SYNTHESIZED_F(SRSO_NO), - SYNTHESIZED_F(SRSO_USER_KERNEL_NO), + F(SRSO_USER_KERNEL_NO), ); kvm_cpu_cap_init(CPUID_8000_0022_EAX,