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[src/trunk]: src When there's no DecodeAssist in hardware, decode manually in...
details: https://anonhg.NetBSD.org/src/rev/bf0e9eb6fee5
branches: trunk
changeset: 447141:bf0e9eb6fee5
user: maxv <maxv%NetBSD.org@localhost>
date: Wed Jan 02 12:18:08 2019 +0000
description:
When there's no DecodeAssist in hardware, decode manually in software. This
is needed on certain AMD CPUs (like mine): the segment base of OUTS can be
overridden, and it is wrong to just assume DS.
We fetch the instruction and look at the prefixes if any to determine the
correct segment.
diffstat:
lib/libnvmm/libnvmm_x86.c | 99 ++++++++++++++++++++++++++++++++--------
sys/dev/nvmm/x86/nvmm_x86_svm.c | 10 +--
2 files changed, 81 insertions(+), 28 deletions(-)
diffs (195 lines):
diff -r 883aec17ebdd -r bf0e9eb6fee5 lib/libnvmm/libnvmm_x86.c
--- a/lib/libnvmm/libnvmm_x86.c Wed Jan 02 09:04:09 2019 +0000
+++ b/lib/libnvmm/libnvmm_x86.c Wed Jan 02 12:18:08 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: libnvmm_x86.c,v 1.7 2018/12/29 17:54:54 maxv Exp $ */
+/* $NetBSD: libnvmm_x86.c,v 1.8 2019/01/02 12:18:08 maxv Exp $ */
/*
* Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -76,13 +76,14 @@
printf("| -> RBX=%p\n", (void *)state.gprs[NVMM_X64_GPR_RBX]);
printf("| -> RCX=%p\n", (void *)state.gprs[NVMM_X64_GPR_RCX]);
for (i = 0; i < NVMM_X64_NSEG; i++) {
- printf("| -> %s: sel=0x%lx base=%p, limit=%p, P=%d\n",
+ printf("| -> %s: sel=0x%lx base=%p, limit=%p, P=%d, D=%d\n",
segnames[i],
state.segs[i].selector,
(void *)state.segs[i].base,
(void *)state.segs[i].limit,
- state.segs[i].attrib.p);
+ state.segs[i].attrib.p, state.segs[i].attrib.def32);
}
+ printf("| -> CPL=%p\n", (void *)state.misc[NVMM_X64_MISC_CPL]);
return 0;
}
@@ -619,6 +620,8 @@
/* -------------------------------------------------------------------------- */
+static int fetch_segment(struct nvmm_machine *, struct nvmm_x64_state *);
+
int
nvmm_assist_io(struct nvmm_machine *mach, nvmm_cpuid_t cpuid,
struct nvmm_exit *exit)
@@ -628,7 +631,7 @@
uint64_t cnt;
gvaddr_t gva;
int reg = 0; /* GCC */
- int ret;
+ int ret, seg;
if (__predict_false(exit->reason != NVMM_EXIT_IO)) {
errno = EINVAL;
@@ -659,8 +662,19 @@
gva &= mask_from_adsize(exit->u.io.address_size);
if (!is_long_mode(&state)) {
- ret = segment_apply(&state.segs[exit->u.io.seg], &gva,
- io.size);
+ if (exit->u.io.seg != -1) {
+ seg = exit->u.io.seg;
+ } else {
+ if (io.in) {
+ seg = NVMM_X64_SEG_ES;
+ } else {
+ seg = fetch_segment(mach, &state);
+ if (seg == -1)
+ return -1;
+ }
+ }
+
+ ret = segment_apply(&state.segs[seg], &gva, io.size);
if (ret == -1)
return -1;
}
@@ -2091,24 +2105,27 @@
return 0;
}
-static const uint8_t legpref_table[NLEG] = {
+static const struct {
+ uint8_t byte;
+ int seg;
+} legpref_table[NLEG] = {
/* Group 1 */
- [LEG_LOCK] = 0xF0,
- [LEG_REPN] = 0xF2,
- [LEG_REP] = 0xF3,
+ [LEG_LOCK] = { 0xF0, -1 },
+ [LEG_REPN] = { 0xF2, -1 },
+ [LEG_REP] = { 0xF3, -1 },
/* Group 2 */
- [LEG_OVR_CS] = 0x2E,
- [LEG_OVR_SS] = 0x36,
- [LEG_OVR_DS] = 0x3E,
- [LEG_OVR_ES] = 0x26,
- [LEG_OVR_FS] = 0x64,
- [LEG_OVR_GS] = 0x65,
- [LEG_BRN_TAKEN] = 0x2E,
- [LEG_BRN_NTAKEN] = 0x3E,
+ [LEG_OVR_CS] = { 0x2E, NVMM_X64_SEG_CS },
+ [LEG_OVR_SS] = { 0x36, NVMM_X64_SEG_SS },
+ [LEG_OVR_DS] = { 0x3E, NVMM_X64_SEG_DS },
+ [LEG_OVR_ES] = { 0x26, NVMM_X64_SEG_ES },
+ [LEG_OVR_FS] = { 0x64, NVMM_X64_SEG_FS },
+ [LEG_OVR_GS] = { 0x65, NVMM_X64_SEG_GS },
+ [LEG_BRN_TAKEN] = { 0x2E, -1 },
+ [LEG_BRN_NTAKEN] = { 0x3E, -1 },
/* Group 3 */
- [LEG_OPR_OVR] = 0x66,
+ [LEG_OPR_OVR] = { 0x66, -1 },
/* Group 4 */
- [LEG_ADR_OVR] = 0x67
+ [LEG_ADR_OVR] = { 0x67, -1 },
};
static int
@@ -2122,7 +2139,7 @@
}
for (i = 0; i < NLEG; i++) {
- if (byte == legpref_table[i])
+ if (byte == legpref_table[i].byte)
break;
}
@@ -2451,6 +2468,46 @@
}
static int
+fetch_segment(struct nvmm_machine *mach, struct nvmm_x64_state *state)
+{
+ uint8_t inst_bytes[15], byte;
+ size_t i, n, fetchsize;
+ gvaddr_t gva;
+ int ret, seg;
+
+ fetchsize = sizeof(inst_bytes);
+
+ gva = state->gprs[NVMM_X64_GPR_RIP];
+ if (!is_long_mode(state)) {
+ ret = segment_apply(&state->segs[NVMM_X64_SEG_CS], &gva,
+ fetchsize);
+ if (ret == -1)
+ return -1;
+ }
+
+ ret = read_guest_memory(mach, state, gva, inst_bytes, fetchsize);
+ if (ret == -1)
+ return -1;
+
+ seg = NVMM_X64_SEG_DS;
+ for (n = 0; n < fetchsize; n++) {
+ byte = inst_bytes[n];
+ for (i = 0; i < NLEG; i++) {
+ if (byte != legpref_table[i].byte)
+ continue;
+ if (i >= LEG_OVR_CS && i <= LEG_OVR_GS)
+ seg = legpref_table[i].seg;
+ break;
+ }
+ if (i == NLEG) {
+ break;
+ }
+ }
+
+ return seg;
+}
+
+static int
fetch_instruction(struct nvmm_machine *mach, struct nvmm_x64_state *state,
struct nvmm_exit *exit)
{
diff -r 883aec17ebdd -r bf0e9eb6fee5 sys/dev/nvmm/x86/nvmm_x86_svm.c
--- a/sys/dev/nvmm/x86/nvmm_x86_svm.c Wed Jan 02 09:04:09 2019 +0000
+++ b/sys/dev/nvmm/x86/nvmm_x86_svm.c Wed Jan 02 12:18:08 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: nvmm_x86_svm.c,v 1.7 2018/12/13 16:28:10 maxv Exp $ */
+/* $NetBSD: nvmm_x86_svm.c,v 1.8 2019/01/02 12:18:08 maxv Exp $ */
/*
* Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_svm.c,v 1.7 2018/12/13 16:28:10 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_svm.c,v 1.8 2019/01/02 12:18:08 maxv Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -803,11 +803,7 @@
KASSERT(__SHIFTOUT(info, SVM_EXIT_IO_SEG) < 6);
exit->u.io.seg = seg_to_nvmm[__SHIFTOUT(info, SVM_EXIT_IO_SEG)];
} else {
- if (exit->u.io.type == NVMM_EXIT_IO_IN) {
- exit->u.io.seg = NVMM_X64_SEG_ES;
- } else {
- exit->u.io.seg = NVMM_X64_SEG_DS;
- }
+ exit->u.io.seg = -1;
}
if (info & SVM_EXIT_IO_A64) {
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