xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

KVM: x86: Add helpers to perform CPUID-based guest vendor check

Browse Source 
Add helpers to provide CPUID-based guest vendor checks, i.e. to do the
ugly register comparisons.  Use the new helpers to check for an AMD
guest vendor in guest_cpuid_is_amd() as well as in the existing emulator
flows.

Using the new helpers fixes a _very_ theoretical bug where
guest_cpuid_is_amd() would get a false positive on a non-AMD virtual CPU
with a vendor string beginning with "Auth" due to the previous logic
only checking EBX.  It also fixes a marginally less theoretically bug
where guest_cpuid_is_amd() would incorrectly return false for a guest
CPU with "AMDisbetter!" as its vendor string.

Fixes: a0c0feb579 ("KVM: x86: reserve bit 8 of non-leaf PDPEs and PML4Es in 64-bit mode on AMD")
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
2020-03-04 17:34:32 -08:00
committed by Paolo Bonzini
parent b7fb8488c8
commit 15608ed03f
3 changed files with 33 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/kvm/cpuid.h
View File

@@ -219,7 +219,7 @@ static inline bool guest_cpuid_is_amd(struct kvm_vcpu *vcpu)
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 0, 0);
return best && best->ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx;
return best && is_guest_vendor_amd(best->ebx, best->ecx, best->edx);
}
static inline int guest_cpuid_family(struct kvm_vcpu *vcpu)