[PATCH 3/3] KVM: VMX: Drop manual checks on X86_FEATURE_MSR_IA32_FEAT_CTL

Sean Christopherson
2022-12-03T00:40:41Z

Drop manual checks on X86_FEATURE_MSR_IA32_FEAT_CTL and instead rely
solely on the X86_FEATURE_VMX check to detect VMX support now that VMX is
disabled via apply_cpuid_deps() if X86_FEATURE_MSR_IA32_FEAT_CTL isn't
supported.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kernel/cpu/bugs.c | 3 +--
arch/x86/kvm/vmx/vmx.c | 6 ++----
2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 9e84b685328f..3071e2a97f0d 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -2222,8 +2222,7 @@ static ssize_t l1tf_show_state(char *buf)

static ssize_t itlb_multihit_show_state(char *buf)
{
- if (!boot_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
- !boot_cpu_has(X86_FEATURE_VMX))
+ if (!boot_cpu_has(X86_FEATURE_VMX))
return sysfs_emit(buf, "KVM: Mitigation: VMX unsupported\n");
else if (!(cr4_read_shadow() & X86_CR4_VMXE))
return sysfs_emit(buf, "KVM: Mitigation: VMX disabled\n");
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 9dba04b6b019..de3fe3932ee8 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -2423,8 +2423,7 @@ static __init int cpu_has_kvm_support(void)

static __init int vmx_disabled_by_bios(void)
{
- return !boot_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
- !boot_cpu_has(X86_FEATURE_VMX);
+ return !boot_cpu_has(X86_FEATURE_VMX);
}

static int kvm_cpu_vmxon(u64 vmxon_pointer)
@@ -7413,8 +7412,7 @@ static int __init vmx_check_processor_compat(void)
struct vmcs_config vmcs_conf;
struct vmx_capability vmx_cap;

- if (!this_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
- !this_cpu_has(X86_FEATURE_VMX)) {
+ if (!this_cpu_has(X86_FEATURE_VMX)) {
pr_err("kvm: VMX is disabled on CPU %d\n", smp_processor_id());
return -EIO;
}
--
2.39.0.rc0.267.gcb52ba06e7-goog