KVM: nVMX: expose VPID capability to L1

Expose VPID capability to L1. For nested guests, we don't do anything
specific for single context invalidation. Hence, only advertise support
for global context invalidation. The major benefit of nested VPID comes
from having separate vpids when switching between L1 and L2, and also
when L2's vCPUs not sched in/out on L1.
Reviewed-by: Wincy Van <fanwenyi0529@gmail.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -2622,7 +2622,11 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 	} else
 		vmx->nested.nested_vmx_ept_caps = 0;
 
-	vmx->nested.nested_vmx_vpid_caps = 0;
+	if (enable_vpid)
+		vmx->nested.nested_vmx_vpid_caps = VMX_VPID_INVVPID_BIT |
+				VMX_VPID_EXTENT_GLOBAL_CONTEXT_BIT;
+	else
+		vmx->nested.nested_vmx_vpid_caps = 0;
 
 	if (enable_unrestricted_guest)
 		vmx->nested.nested_vmx_secondary_ctls_high |=
@@ -2739,7 +2743,8 @@ static int vmx_get_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
 		break;
 	case MSR_IA32_VMX_EPT_VPID_CAP:
 		/* Currently, no nested vpid support */
-		*pdata = vmx->nested.nested_vmx_ept_caps;
+		*pdata = vmx->nested.nested_vmx_ept_caps |
+			((u64)vmx->nested.nested_vmx_vpid_caps << 32);
 		break;
 	default:
 		return 1;