KVM: pass through CPUID(0x80000006)

Return the host's L2 cache and TLB information for CPUID.0x80000006
instead of zeroing out the entry as part of KVM_GET_SUPPORTED_CPUID.
This allows a userspace VMM to feed KVM_GET_SUPPORTED_CPUID's output
directly into KVM_SET_CPUID2 (without breaking the guest).

Signed-off-by: Eric Northup (Google) <digitaleric@gmail.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Jon Cargille <jcargill@google.com>
Message-Id: <20200415012320.236065-1-jcargill@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 901cd1f..6828be9 100644 (file)
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -728,6 +728,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
                cpuid_entry_override(entry, CPUID_8000_0001_EDX);
                cpuid_entry_override(entry, CPUID_8000_0001_ECX);
                break;
+       case 0x80000006:
+               /* L2 cache and TLB: pass through host info. */
+               break;
        case 0x80000007: /* Advanced power management */
                /* invariant TSC is CPUID.80000007H:EDX[8] */
                entry->edx &= (1 << 8);