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commit396d2e878fupstream. The host reports support for the synthetic feature X86_FEATURE_SSBD when any of the three following hardware features are set: CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] CPUID.80000008H:EBX.AMD_SSBD[bit 24] CPUID.80000008H:EBX.VIRT_SSBD[bit 25] Either of the first two hardware features implies the existence of the IA32_SPEC_CTRL MSR, but CPUID.80000008H:EBX.VIRT_SSBD[bit 25] does not. Therefore, CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] should only be set in the guest if CPUID.(EAX=7,ECX=0):EDX.SSBD[bit 31] or CPUID.80000008H:EBX.AMD_SSBD[bit 24] is set on the host. Fixes:0c54914d0c("KVM: x86: use Intel speculation bugs and features as derived in generic x86 code") Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Jacob Xu <jacobhxu@google.com> Reviewed-by: Peter Shier <pshier@google.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Reported-by: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [bwh: Backported to 4.x: adjust indentation] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>