[PATCH v4 16/19] KVM: VMX: Check for full VMX support when verifying CPU compatibility

[Sean Christopherson]

Explicitly check the current CPU's IA32_FEAT_CTL and VMX feature flags
when verifying compatibility across physical CPUs.  This effectively
adds a check on IA32_FEAT_CTL to ensure that VMX is fully enabled on
all CPUs.

Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
 arch/x86/kvm/vmx/vmx.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 6020f04fe1a8..38d17c78e19d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6846,6 +6846,12 @@ 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)) {
+		pr_err("kvm: VMX is disabled on CPU %d\n", smp_processor_id());
+		return -EIO;
+	}
+
 	if (setup_vmcs_config(&vmcs_conf, &vmx_cap) < 0)
 		return -EIO;
 	if (nested)
-- 
2.24.0