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 <pbonzini@xxxxxxxxxx> --- arch/x86/kvm/cpuid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 2cbb3874ad39..8eb3a88707f2 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, -- 2.43.5
