On Tue, Nov 15, 2022, Huang, Kai wrote:

On Wed, 2022-11-02 at 23:19 +0000, Sean Christopherson wrote:

quoted

+static bool __init kvm_is_vmx_supported(void)
+{
+	if (!cpu_has_vmx()) {
+		pr_err("CPU doesn't support VMX\n");
+		return false;
+	}
+
+	if (!boot_cpu_has(X86_FEATURE_MSR_IA32_FEAT_CTL) ||
+	    !boot_cpu_has(X86_FEATURE_VMX)) {
+		pr_err("VMX not enabled in MSR_IA32_FEAT_CTL\n");
+		return false;
+	}
+
+	return true;
+}
+
 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("VMX is disabled on CPU %d\n", smp_processor_id());
+	if (!kvm_is_vmx_supported())
 		return -EIO;
-	}
 

Looks there's a functional change here -- the old code checks local cpu's
feature bits but the new code always checks bsp's feature bits.  Should have no
problem I think, though.

Ouch.  The bad check will defeat the purpose of doing compat checks.  Nice catch!