Commit 2746a6b7 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: x86: skip host CPUID call for hypervisor leaves 



Hypervisor leaves are always synthesized by __do_cpuid_func; just return
zeroes and do not ask the host.  Even on nested virtualization, a value
from another hypervisor would be bogus, because all hypercalls and MSRs
are processed by KVM.

Reviewed-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9d68c6f6

arch/x86/kvm/cpuid.c

+9 −1
Original line number Diff line number Diff line
@@ -712,9 +712,17 @@ 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);