From: Sean Christopherson Date: Mon, 2 Mar 2020 23:56:52 +0000 (-0800) Subject: KVM: x86: Do host CPUID at load time to mask KVM cpu caps X-Git-Tag: v5.10.7~2921^2~93 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d8577a4c238f8bd3089bfb428fece97f14eaabad;p=platform%2Fkernel%2Flinux-rpi.git KVM: x86: Do host CPUID at load time to mask KVM cpu caps Mask kvm_cpu_caps based on host CPUID in preparation for overriding the CPUID results during KVM_GET_SUPPORTED_CPUID instead of doing the masking at runtime. Note, masking may or may not be necessary, e.g. the kernel rarely, if ever, sets real CPUID bits that are not supported by hardware. But, the code is cheap and only runs once at load, so an abundance of caution is warranted. No functional change intended. Reviewed-by: Vitaly Kuznetsov Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index d4ada8f..80fccfd 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -263,8 +263,16 @@ out: static __always_inline void kvm_cpu_cap_mask(enum cpuid_leafs leaf, u32 mask) { + const struct cpuid_reg cpuid = x86_feature_cpuid(leaf * 32); + struct kvm_cpuid_entry2 entry; + reverse_cpuid_check(leaf); kvm_cpu_caps[leaf] &= mask; + + cpuid_count(cpuid.function, cpuid.index, + &entry.eax, &entry.ebx, &entry.ecx, &entry.edx); + + kvm_cpu_caps[leaf] &= *__cpuid_entry_get_reg(&entry, &cpuid); } void kvm_set_cpu_caps(void)