[PATCH v3 2/8] KVM: X86: Go on updating other CPUID leaves when leaf 1 is absent

From: Xiaoyao Li
Date: Wed Jul 08 2020 - 02:51:13 EST


As handling of bits out of leaf 1 added over time, kvm_update_cpuid()
should not return directly if leaf 1 is absent, but should go on
updateing other CPUID leaves.

Keep the update of apic->lapic_timer.timer_mode_mask in a separate
wrapper, to minimize churn for code since it will be moved out of this
function in a future patch.

Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 1d13bad42bf9..0e3a23c2ea55 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -60,18 +60,17 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu)
struct kvm_lapic *apic = vcpu->arch.apic;

best = kvm_find_cpuid_entry(vcpu, 1, 0);
- if (!best)
- return 0;
-
- /* Update OSXSAVE bit */
- if (boot_cpu_has(X86_FEATURE_XSAVE) && best->function == 0x1)
- cpuid_entry_change(best, X86_FEATURE_OSXSAVE,
+ if (best) {
+ /* Update OSXSAVE bit */
+ if (boot_cpu_has(X86_FEATURE_XSAVE))
+ cpuid_entry_change(best, X86_FEATURE_OSXSAVE,
kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE));

- cpuid_entry_change(best, X86_FEATURE_APIC,
+ cpuid_entry_change(best, X86_FEATURE_APIC,
vcpu->arch.apic_base & MSR_IA32_APICBASE_ENABLE);
+ }

- if (apic) {
+ if (best && apic) {
if (cpuid_entry_has(best, X86_FEATURE_TSC_DEADLINE_TIMER))
apic->lapic_timer.timer_mode_mask = 3 << 17;
else
--
2.18.4