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kvm: x86: SRSO_USER_KERNEL_NO is not synthesized

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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@redhat.com>
This commit is contained in:
Paolo Bonzini 2025-02-04 11:13:24 -05:00
parent 2014c95afe
commit ee3a66f431
1 changed files with 1 additions and 1 deletions
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2
arch/x86/kvm/cpuid.c
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@ -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,