nVMX: Advertise PML to L1 hypervisor

Advertise the PML bit in vmcs12 but don't try to enable
it in hardware when running L2 since L0 is emulating it. Also,
preserve L0's settings for PML since it may still
want to log writes.
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -2766,8 +2766,11 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 		vmx->nested.nested_vmx_ept_caps |= VMX_EPT_EXTENT_GLOBAL_BIT |
 			VMX_EPT_EXTENT_CONTEXT_BIT | VMX_EPT_2MB_PAGE_BIT |
 			VMX_EPT_1GB_PAGE_BIT;
-	       if (enable_ept_ad_bits)
+		if (enable_ept_ad_bits) {
+			vmx->nested.nested_vmx_secondary_ctls_high |=
+				SECONDARY_EXEC_ENABLE_PML;
 		       vmx->nested.nested_vmx_ept_caps |= VMX_EPT_AD_BIT;
+		}
 	} else
 		vmx->nested.nested_vmx_ept_caps = 0;
 
@@ -8129,7 +8132,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 	case EXIT_REASON_PREEMPTION_TIMER:
 		return false;
 	case EXIT_REASON_PML_FULL:
-		/* We don't expose PML support to L1. */
+		/* We emulate PML support to L1. */
 		return false;
 	default:
 		return true;
@@ -9924,7 +9927,7 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 			  bool from_vmentry, u32 *entry_failure_code)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	u32 exec_control;
+	u32 exec_control, vmcs12_exec_ctrl;
 
 	vmcs_write16(GUEST_ES_SELECTOR, vmcs12->guest_es_selector);
 	vmcs_write16(GUEST_CS_SELECTOR, vmcs12->guest_cs_selector);
@@ -10055,8 +10058,11 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
 				  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
 				  SECONDARY_EXEC_APIC_REGISTER_VIRT);
 		if (nested_cpu_has(vmcs12,
-				CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
-			exec_control |= vmcs12->secondary_vm_exec_control;
+				   CPU_BASED_ACTIVATE_SECONDARY_CONTROLS)) {
+			vmcs12_exec_ctrl = vmcs12->secondary_vm_exec_control &
+				~SECONDARY_EXEC_ENABLE_PML;
+			exec_control |= vmcs12_exec_ctrl;
+		}
 
 		if (exec_control & SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY) {
 			vmcs_write64(EOI_EXIT_BITMAP0,