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Subject[PATCH] KVM: x86: skip host CPUID call for hypervisor leaves
Date
Hypervisor leaves are always synthesized by __do_cpuid_func.  Just return
zeroes and do not ask the host, it would return a bogus value anyway if
it were used.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/cpuid.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 3902c28fb6cb..fd949e89120a 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -692,9 +692,17 @@ static struct kvm_cpuid_entry2 *do_host_cpuid(struct kvm_cpuid_array *array,

entry = &array->entries[array->nent++];

+ memset(entry, 0, sizeof(*entry));
entry->function = function;
entry->index = index;
- entry->flags = 0;
+ switch (function & 0xC0000000) {
+ case 0x40000000:
+ /* Hypervisor leaves are always synthesized by __do_cpuid_func. */
+ return entry;
+
+ default:
+ break;
+ }

cpuid_count(entry->function, entry->index,
&entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
--
2.31.1
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