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KVM: x86: Drop redundant boot cpu checks on SSBD feature bits

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Drop redundant checks when "emulating" SSBD feature across vendors,
i.e. advertising the AMD variant when running on an Intel CPU and vice
versa.  Both SPEC_CTRL_SSBD and AMD_SSBD are already defined in the
leaf-specific feature masks and are *not* forcefully set by the kernel,
i.e. will already be set in the entry when supported by the host.

Functionally, this changes nothing, but the redundant check is
confusing, especially when considering future patches that will further
differentiate between "real" and "emulated" feature bits.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2020-03-02 15:56:15 -08:00 committed by Paolo Bonzini
parent aceac6e570
commit acfad336ec
1 changed files with 2 additions and 4 deletions
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6
arch/x86/kvm/cpuid.c
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@ -405,8 +405,7 @@ static inline void do_cpuid_7_mask(struct kvm_cpuid_entry2 *entry)
entry->edx |= F(SPEC_CTRL);
if (boot_cpu_has(X86_FEATURE_STIBP))
entry->edx |= F(INTEL_STIBP);
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
boot_cpu_has(X86_FEATURE_AMD_SSBD))
if (boot_cpu_has(X86_FEATURE_AMD_SSBD))
entry->edx |= F(SPEC_CTRL_SSBD);
/*
* We emulate ARCH_CAPABILITIES in software even
@ -780,8 +779,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
entry->ebx |= F(AMD_IBRS);
if (boot_cpu_has(X86_FEATURE_STIBP))
entry->ebx |= F(AMD_STIBP);
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
boot_cpu_has(X86_FEATURE_AMD_SSBD))
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
entry->ebx |= F(AMD_SSBD);
if (!boot_cpu_has_bug(X86_BUG_SPEC_STORE_BYPASS))
entry->ebx |= F(AMD_SSB_NO);