Introduce a new function to obtain properly sized input data, and convert

i8253/i8259/mc146818 emulation to use this.

5 files changed, 36 insertions, 18 deletions

diff --git a/usr.sbin/vmd/i8253.c b/usr.sbin/vmd/i8253.c
index 3f9b7383d7b..2979d492a93 100644
--- a/usr.sbin/vmd/i8253.c
+++ b/usr.sbin/vmd/i8253.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: i8253.c,v 1.9 2017/03/24 11:08:43 reyk Exp $ */
+/* $OpenBSD: i8253.c,v 1.10 2017/03/25 07:46:24 mlarkin Exp $ */
 /*
  * Copyright (c) 2016 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -133,7 +133,7 @@ vcpu_exit_i8253(struct vm_run_params *vrp)
 	struct timeval now, delta;
 	union vm_exit *vei = vrp->vrp_exit;
 
-	out_data = vei->vei.vei_data & 0xFF;
+	out_data = get_input_data(vei);
 
 	if (vei->vei.vei_port == TIMER_CTRL) {
 		if (vei->vei.vei_dir == VEI_DIR_OUT) { /* OUT instruction */
diff --git a/usr.sbin/vmd/i8259.c b/usr.sbin/vmd/i8259.c
index 1be0daf0251..61229d79b6f 100644
--- a/usr.sbin/vmd/i8259.c
+++ b/usr.sbin/vmd/i8259.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: i8259.c,v 1.10 2017/03/24 11:08:43 reyk Exp $ */
+/* $OpenBSD: i8259.c,v 1.11 2017/03/25 07:46:24 mlarkin Exp $ */
 /*
  * Copyright (c) 2016 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -556,7 +556,7 @@ static void
 i8259_io_write(union vm_exit *vei)
 {
 	uint16_t port = vei->vei.vei_port;
-	uint8_t data = vei->vei.vei_data;
+	uint8_t data = get_input_data(vei);
 	uint8_t n = 0;
 
 	switch (port) {
diff --git a/usr.sbin/vmd/mc146818.c b/usr.sbin/vmd/mc146818.c
index 59b5c57a2c9..5c265457dde 100644
--- a/usr.sbin/vmd/mc146818.c
+++ b/usr.sbin/vmd/mc146818.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mc146818.c,v 1.8 2017/03/23 07:59:41 mlarkin Exp $ */
+/* $OpenBSD: mc146818.c,v 1.9 2017/03/25 07:46:24 mlarkin Exp $ */
 /*
  * Copyright (c) 2016 Mike Larkin <mlarkin@openbsd.org>
  *
@@ -249,7 +249,9 @@ vcpu_exit_mc146818(struct vm_run_params *vrp)
 	union vm_exit *vei = vrp->vrp_exit;
 	uint16_t port = vei->vei.vei_port;
 	uint8_t dir = vei->vei.vei_dir;
-	uint32_t data = vei->vei.vei_data & 0xFF;
+	uint32_t data;
+
+	data = get_input_data(vei);
 
 	if (port == IO_RTC) {
 		/* Discard NMI bit */
@@ -259,16 +261,10 @@ vcpu_exit_mc146818(struct vm_run_params *vrp)
 		if (dir == 0) {
 			if (data < (NVRAM_SIZE))
 				rtc.idx = data;
-			else {
-				log_warnx("%s: mc146818 bogus register 0x%x",
-				    __func__, data);
+			else
 				rtc.idx = MC_REGD;
-			}
-		} else {
-			log_warnx("%s: mc146818 illegal read from port 0x%x",
-			    __func__, port);
-			set_return_data(vei, 0xFF);
-		}
+		} else
+			set_return_data(vei, rtc.idx);
 	} else if (port == IO_RTC + 1) {
 		if (dir == 0) {
 			switch (rtc.idx) {
@@ -291,7 +287,6 @@ vcpu_exit_mc146818(struct vm_run_params *vrp)
 				log_warnx("%s: mc146818 illegal reg %x\n",
 				    __func__, rtc.idx);
 			}
-			rtc.idx = MC_REGD;
 		} else {
 			data = rtc.regs[rtc.idx];
 			set_return_data(vei, data);
@@ -300,7 +295,6 @@ vcpu_exit_mc146818(struct vm_run_params *vrp)
 				/* Reset IRQ state */
 				rtc.regs[MC_REGC] &= ~MC_REGC_PF;
 			}
-			rtc.idx = MC_REGD;
 		}
 	} else {
 		log_warnx("%s: mc146818 unknown port 0x%x",
diff --git a/usr.sbin/vmd/vm.c b/usr.sbin/vmd/vm.c
index 896364b7c07..ad3ca6d25c6 100644
--- a/usr.sbin/vmd/vm.c
+++ b/usr.sbin/vmd/vm.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vm.c,v 1.6 2017/03/24 08:04:02 mlarkin Exp $	*/
+/*	$OpenBSD: vm.c,v 1.7 2017/03/25 07:46:24 mlarkin Exp $	*/
 
 /*
  * Copyright (c) 2015 Mike Larkin <mlarkin@openbsd.org>
@@ -1333,3 +1333,26 @@ set_return_data(union vm_exit *vei, uint32_t data)
 		break;	
 	}
 }
+
+/*
+ * get_input_data
+ *
+ * Utility function for manipulating register data in vm exit info structs. This
+ * function ensures that the data is copied from the vei->vei.vei_data field with
+ * the proper size for the operation being performed.
+ *
+ * Parameters:
+ *  vei: exit information
+ */
+uint32_t
+get_input_data(union vm_exit *vei)
+{
+	switch (vei->vei.vei_size) {
+	case 1: return vei->vei.vei_data & 0xFF;
+	case 2: return vei->vei.vei_data & 0xFFFF;
+	case 4: return vei->vei.vei_data;
+	}
+
+	log_warnx("%s: invalid i/o size %d", __func__, vei->vei.vei_size);
+	return 0;
+}
diff --git a/usr.sbin/vmd/vmm.h b/usr.sbin/vmd/vmm.h
index 0104225dae9..5e5bb50dceb 100644
--- a/usr.sbin/vmd/vmm.h
+++ b/usr.sbin/vmd/vmm.h
@@ -20,3 +20,4 @@ typedef uint8_t (*io_fn_t)(struct vm_run_params *);
 
 void vcpu_assert_pic_irq(uint32_t, uint32_t, int);
 void set_return_data(union vm_exit *, uint32_t);
+uint32_t get_input_data(union vm_exit *);