KVM: nVMX: Add support for rdtscp

If the guest CPU is supposed to support rdtscp and the host has rdtscp
enabled in the secondary execution controls, we can also expose this
feature to L1. Just extend nested_vmx_exit_handled to properly route
EXIT_REASON_RDTSCP.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/include/uapi/asm/vmx.h

@@ -67,6 +67,7 @@
 #define EXIT_REASON_EPT_VIOLATION       48
 #define EXIT_REASON_EPT_MISCONFIG       49
 #define EXIT_REASON_INVEPT              50
+#define EXIT_REASON_RDTSCP              51
 #define EXIT_REASON_PREEMPTION_TIMER    52
 #define EXIT_REASON_INVVPID             53
 #define EXIT_REASON_WBINVD              54

arch/x86/kvm/vmx.c

@@ -2467,6 +2467,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 	vmx->nested.nested_vmx_secondary_ctls_low = 0;
 	vmx->nested.nested_vmx_secondary_ctls_high &=
 		SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+		SECONDARY_EXEC_RDTSCP |
 		SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
 		SECONDARY_EXEC_APIC_REGISTER_VIRT |
 		SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
@@ -7510,7 +7511,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 		return nested_cpu_has(vmcs12, CPU_BASED_INVLPG_EXITING);
 	case EXIT_REASON_RDPMC:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDPMC_EXITING);
-	case EXIT_REASON_RDTSC:
+	case EXIT_REASON_RDTSC: case EXIT_REASON_RDTSCP:
 		return nested_cpu_has(vmcs12, CPU_BASED_RDTSC_EXITING);
 	case EXIT_REASON_VMCALL: case EXIT_REASON_VMCLEAR:
 	case EXIT_REASON_VMLAUNCH: case EXIT_REASON_VMPTRLD:
@@ -8517,6 +8518,9 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
 						exec_control);
 			}
 		}
+		if (nested && !vmx->rdtscp_enabled)
+			vmx->nested.nested_vmx_secondary_ctls_high &=
+				~SECONDARY_EXEC_RDTSCP;
 	}
 
 	/* Exposing INVPCID only when PCID is exposed */
@@ -9146,8 +9150,9 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 			exec_control &= ~SECONDARY_EXEC_RDTSCP;
 		/* Take the following fields only from vmcs12 */
 		exec_control &= ~(SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
+				  SECONDARY_EXEC_RDTSCP |
 				  SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
-                                  SECONDARY_EXEC_APIC_REGISTER_VIRT);
+				  SECONDARY_EXEC_APIC_REGISTER_VIRT);
 		if (nested_cpu_has(vmcs12,
 				CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
 			exec_control |= vmcs12->secondary_vm_exec_control;