From: dv <dv@openbsd.org>
Date: Fri, 13 May 2022 18:19:32 +0000 (+0000)
Subject: vmm: add additional fault type, fixing vm receive
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=8732c71624623210e9e8217b22269e93892f230f;p=openbsd

vmm: add additional fault type, fixing vm receive

After vmm(4)/vmd(8) "receive" a vm via vmctl(8), vmd on Intel hosts
was incorrectly identifying the fault type for nested page fault
exits and resetting the vm. This commit adds a new fault type to
signify the page fault was serviced in vmm and any exit to userland
does not require an assist.

ok mlarkin@
---

diff --git a/sys/arch/amd64/amd64/vmm.c b/sys/arch/amd64/amd64/vmm.c
index 090feb6623a..2784aaf654f 100644
--- a/sys/arch/amd64/amd64/vmm.c
+++ b/sys/arch/amd64/amd64/vmm.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vmm.c,v 1.308 2022/05/04 02:24:26 dv Exp $	*/
+/*	$OpenBSD: vmm.c,v 1.309 2022/05/13 18:19:32 dv Exp $	*/
 /*
  * Copyright (c) 2014 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -5732,14 +5732,16 @@ vmx_fault_page(struct vcpu *vcpu, paddr_t gpa)
 	int fault_type, ret;
 
 	fault_type = vmx_get_guest_faulttype();
-	if (fault_type == -1) {
+	switch (fault_type) {
+	case -1:
 		printf("%s: invalid fault type\n", __func__);
 		return (EINVAL);
-	}
-
-	if (fault_type == VM_FAULT_PROTECT) {
+	case VM_FAULT_PROTECT:
 		vcpu->vc_exit.vee.vee_fault_type = VEE_FAULT_PROTECT;
 		return (EAGAIN);
+	default:
+		vcpu->vc_exit.vee.vee_fault_type = VEE_FAULT_HANDLED;
+		break;
 	}
 
 	/* We may sleep during uvm_fault(9), so reload VMCS. */
diff --git a/sys/arch/amd64/include/vmmvar.h b/sys/arch/amd64/include/vmmvar.h
index f798674dd0f..42b811a2e42 100644
--- a/sys/arch/amd64/include/vmmvar.h
+++ b/sys/arch/amd64/include/vmmvar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vmmvar.h,v 1.75 2022/05/03 21:39:19 dv Exp $	*/
+/*	$OpenBSD: vmmvar.h,v 1.76 2022/05/13 18:19:32 dv Exp $	*/
 /*
  * Copyright (c) 2014 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -324,7 +324,8 @@ enum {
 };
 
 enum {
-	VEE_FAULT_PROTECT
+	VEE_FAULT_HANDLED,
+	VEE_FAULT_PROTECT,
 };
 
 enum {