nvmx: mark ept single context invalidation as supported

Commit 4b855078 ("KVM: nVMX: Don't advertise single
context invalidation for invept") removed advertising
single context invalidation since the spec does not mandate it.
However, some hypervisors (such as ESX) require it to be present
before willing to use ept in a nested environment. Advertise it
and fallback to the global case.
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -2809,12 +2809,8 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
 			vmx->nested.nested_vmx_ept_caps |=
 				VMX_EPT_EXECUTE_ONLY_BIT;
 		vmx->nested.nested_vmx_ept_caps &= vmx_capability.ept;
-		/*
-		 * For nested guests, we don't do anything specific
-		 * for single context invalidation. Hence, only advertise
-		 * support for global context invalidation.
-		 */
-		vmx->nested.nested_vmx_ept_caps |= VMX_EPT_EXTENT_GLOBAL_BIT;
+		vmx->nested.nested_vmx_ept_caps |= VMX_EPT_EXTENT_GLOBAL_BIT |
+			VMX_EPT_EXTENT_CONTEXT_BIT;
 	} else
 		vmx->nested.nested_vmx_ept_caps = 0;
 
@@ -7608,12 +7604,16 @@ static int handle_invept(struct kvm_vcpu *vcpu)
 
 	switch (type) {
 	case VMX_EPT_EXTENT_GLOBAL:
+	/*
+	 * TODO: track mappings and invalidate
+	 * single context requests appropriately
+	 */
+	case VMX_EPT_EXTENT_CONTEXT:
 		kvm_mmu_sync_roots(vcpu);
 		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
 		nested_vmx_succeed(vcpu);
 		break;
 	default:
-		/* Trap single context invalidation invept calls */
 		BUG_ON(1);
 		break;
 	}