[RFC PATCH v6 03/36] KVM: x86: Zero out entire Hyper-V CPUID cache before processing entries

Sean Christopherson
2022-08-24T03:03:40Z

Wipe the whole 'hv_vcpu->cpuid_cache' with memset() instead of having to
zero each particular member when the corresponding CPUID entry was not
found.

No functional change intended.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/hyperv.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index ed804447589c..611c349a08bf 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -2005,31 +2005,24 @@ void kvm_hv_set_cpuid(struct kvm_vcpu *vcpu)

hv_vcpu = to_hv_vcpu(vcpu);

+ memset(&hv_vcpu->cpuid_cache, 0, sizeof(hv_vcpu->cpuid_cache));
+
entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_FEATURES);
if (entry) {
hv_vcpu->cpuid_cache.features_eax = entry->eax;
hv_vcpu->cpuid_cache.features_ebx = entry->ebx;
hv_vcpu->cpuid_cache.features_edx = entry->edx;
- } else {
- hv_vcpu->cpuid_cache.features_eax = 0;
- hv_vcpu->cpuid_cache.features_ebx = 0;
- hv_vcpu->cpuid_cache.features_edx = 0;
}

entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_ENLIGHTMENT_INFO);
if (entry) {
hv_vcpu->cpuid_cache.enlightenments_eax = entry->eax;
hv_vcpu->cpuid_cache.enlightenments_ebx = entry->ebx;
- } else {
- hv_vcpu->cpuid_cache.enlightenments_eax = 0;
- hv_vcpu->cpuid_cache.enlightenments_ebx = 0;
}

entry = kvm_find_cpuid_entry(vcpu, HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES);
if (entry)
hv_vcpu->cpuid_cache.syndbg_cap_eax = entry->eax;
- else
- hv_vcpu->cpuid_cache.syndbg_cap_eax = 0;
}

int kvm_hv_set_enforce_cpuid(struct kvm_vcpu *vcpu, bool enforce)
--
2.37.1.595.g718a3a8f04-goog