KVM: TDX: Skip updating CPU dirty logging request for TDs

JIRA: https://issues.redhat.com/browse/RHEL-47242

commit 1f62531
Author: Paolo Bonzini <[email protected]>
Date:   Wed Feb 19 07:43:51 2025 -0500

    KVM: TDX: Skip updating CPU dirty logging request for TDs

    Wrap vmx_update_cpu_dirty_logging so as to ignore requests to update
    CPU dirty logging for TDs, as basic TDX does not support the PML feature.
    Invoking vmx_update_cpu_dirty_logging() for TDs would cause an incorrect
    access to a kvm_vmx struct for a TDX VM, so block that before it happens.

    Signed-off-by: Yan Zhao <[email protected]>
    Signed-off-by: Paolo Bonzini <[email protected]>

Signed-off-by: Maxim Levitsky <[email protected]>

Author: Maxim Levitsky

arch/x86/kvm/vmx/main.c

@@ -129,6 +129,18 @@ static void vt_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	vmx_vcpu_load(vcpu, cpu);
 }
 
+static void vt_update_cpu_dirty_logging(struct kvm_vcpu *vcpu)
+{
+	/*
+	 * Basic TDX does not support feature PML. KVM does not enable PML in
+	 * TD's VMCS, nor does it allocate or flush PML buffer for TDX.
+	 */
+	if (WARN_ON_ONCE(is_td_vcpu(vcpu)))
+		return;
+
+	vmx_update_cpu_dirty_logging(vcpu);
+}
+
 static void vt_flush_tlb_all(struct kvm_vcpu *vcpu)
 {
 	if (is_td_vcpu(vcpu)) {
@@ -322,7 +334,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.check_intercept = vmx_check_intercept,
 	.handle_exit_irqoff = vmx_handle_exit_irqoff,
 
-	.update_cpu_dirty_logging = vmx_update_cpu_dirty_logging,
+	.update_cpu_dirty_logging = vt_update_cpu_dirty_logging,
 
 	.nested_ops = &vmx_nested_ops,