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authorJim Mattson <jmattson@google.com>2019-09-25 17:04:18 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2019-09-26 12:31:32 +0200
commit5f41a37b151f6459e0b650a2f4d1d59b6c02d1ab (patch)
treebe89af50e756d4c3c58365c68570b257ac88dc94
parent43561123ab3759eb6ff47693aec1a307af0aef83 (diff)
downloadlinux-5f41a37b151f6459e0b650a2f4d1d59b6c02d1ab.tar.bz2
kvm: x86: Use AMD CPUID semantics for AMD vCPUs
When the guest CPUID information represents an AMD vCPU, return all zeroes for queries of undefined CPUID leaves, whether or not they are in range. Signed-off-by: Jim Mattson <jmattson@google.com> Fixes: bd22f5cfcfe8f6 ("KVM: move and fix substitue search for missing CPUID entries") Reviewed-by: Marc Orr <marcorr@google.com> Reviewed-by: Peter Shier <pshier@google.com> Reviewed-by: Jacob Xu <jacobhxu@google.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/cpuid.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index a26a1ae03145..ce4a1b3cc3e8 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -998,9 +998,11 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
/*
* Intel CPUID semantics treats any query for an out-of-range
* leaf as if the highest basic leaf (i.e. CPUID.0H:EAX) were
- * requested.
+ * requested. AMD CPUID semantics returns all zeroes for any
+ * undefined leaf, whether or not the leaf is in range.
*/
- if (!entry && check_limit && !cpuid_function_in_range(vcpu, function)) {
+ if (!entry && check_limit && !guest_cpuid_is_amd(vcpu) &&
+ !cpuid_function_in_range(vcpu, function)) {
max = kvm_find_cpuid_entry(vcpu, 0, 0);
if (max) {
function = max->eax;