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| author |   Paolo Bonzini <pbonzini@redhat.com> | 2021-10-28 13:15:55 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-02-10 13:47:16 -0500 |
| commit | 2746a6b72ab9a92bd188c4ac3e4122ee1c18f754 (patch) | |
| tree | e6158f71d1ee8f01ea9bb57d6de43329714c4ab4 /arch/x86/kvm/cpuid.c | |
| parent | KVM: x86: Remove unused "flags" of kvm_pv_kick_cpu_op() (diff) | |
| download | wireguard-linux-2746a6b72ab9a92bd188c4ac3e4122ee1c18f754.tar.xz wireguard-linux-2746a6b72ab9a92bd188c4ac3e4122ee1c18f754.zip | |
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: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 494d4d351859..ff756cdc31ce 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -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); |