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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2020-03-04 17:34:32 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-03-16 17:58:47 +0100 |
| commit | 15608ed03f10a1414188612b0ee9653e3c78bbd9 (patch) | |
| tree | ac09dad5dac942f2aece0e77a244c33326bdf0a8 /arch/x86/kvm/emulate.c | |
| parent | b7fb8488c85f2b5304e90d954a54d980adde60a4 (diff) | |
| download | lwn-15608ed03f10a1414188612b0ee9653e3c78bbd9.tar.gz lwn-15608ed03f10a1414188612b0ee9653e3c78bbd9.zip | |
KVM: x86: Add helpers to perform CPUID-based guest vendor check
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: a0c0feb57992c ("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>
Diffstat (limited to 'arch/x86/kvm/emulate.c')
| -rw-r--r-- | arch/x86/kvm/emulate.c | 36 |
1 files changed, 8 insertions, 28 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 0bef7762c502..6663f6887d2c 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2723,9 +2723,7 @@ static bool vendor_intel(struct x86_emulate_ctxt *ctxt) eax = ecx = 0; ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false); - return ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx - && ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx - && edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx; + return is_guest_vendor_intel(ebx, ecx, edx); } static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt) @@ -2744,34 +2742,16 @@ static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt) ecx = 0x00000000; ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false); /* - * Intel ("GenuineIntel") - * remark: Intel CPUs only support "syscall" in 64bit - * longmode. Also an 64bit guest with a - * 32bit compat-app running will #UD !! While this - * behaviour can be fixed (by emulating) into AMD - * response - CPUs of AMD can't behave like Intel. + * remark: Intel CPUs only support "syscall" in 64bit longmode. Also a + * 64bit guest with a 32bit compat-app running will #UD !! While this + * behaviour can be fixed (by emulating) into AMD response - CPUs of + * AMD can't behave like Intel. */ - if (ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx && - ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx && - edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx) + if (is_guest_vendor_intel(ebx, ecx, edx)) return false; - /* AMD ("AuthenticAMD") */ - if (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx && - ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx && - edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx) - return true; - - /* AMD ("AMDisbetter!") */ - if (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx && - ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx && - edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx) - return true; - - /* Hygon ("HygonGenuine") */ - if (ebx == X86EMUL_CPUID_VENDOR_HygonGenuine_ebx && - ecx == X86EMUL_CPUID_VENDOR_HygonGenuine_ecx && - edx == X86EMUL_CPUID_VENDOR_HygonGenuine_edx) + if (is_guest_vendor_amd(ebx, ecx, edx) || + is_guest_vendor_hygon(ebx, ecx, edx)) return true; /* |