On Tue, Feb 04, 2025, Paolo Bonzini wrote: > 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> > --- Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
