The branch main has been updated by markj:
URL:
https://cgit.FreeBSD.org/src/commit/?id=5f086566e02a3d21dc840564b90d46f1d3b829bb
commit 5f086566e02a3d21dc840564b90d46f1d3b829bb
Author: Mark Johnston <ma...@freebsd.org>
AuthorDate: 2024-01-23 16:41:13 +0000
Commit: Mark Johnston <ma...@freebsd.org>
CommitDate: 2024-01-23 16:41:13 +0000
bhyve: Prepare to add arm64 support to the gdb stub
In particular:
- Stop assuming that the breakpoint size is one byte.
- Avoid referencing the "rip" field in machine-independent code, use a
helper.
No functional change intended.
Reviewed by: corvink, jhb
MFC after: 1 week
Sponsored by: Innovate UK
Differential Revision: https://reviews.freebsd.org/D43483
---
usr.sbin/bhyve/gdb.c | 37 +++++++++++++++++++++++++------------
1 file changed, 25 insertions(+), 12 deletions(-)
diff --git a/usr.sbin/bhyve/gdb.c b/usr.sbin/bhyve/gdb.c
index 2ef684e82c4b..4f427b1a0863 100644
--- a/usr.sbin/bhyve/gdb.c
+++ b/usr.sbin/bhyve/gdb.c
@@ -69,6 +69,13 @@
*/
#define GDB_SIGNAL_TRAP 5
+#define GDB_BP_SIZE 1
+#define GDB_BP_INSTR (uint8_t []){0xcc}
+#define GDB_PC_REGNAME VM_REG_GUEST_RIP
+
+_Static_assert(sizeof(GDB_BP_INSTR) == GDB_BP_SIZE,
+ "GDB_BP_INSTR has wrong size");
+
static void gdb_resume_vcpus(void);
static void check_command(int fd);
@@ -95,7 +102,7 @@ struct io_buffer {
struct breakpoint {
uint64_t gpa;
- uint8_t shadow_inst;
+ uint8_t shadow_inst[GDB_BP_SIZE];
TAILQ_ENTRY(breakpoint) link;
};
@@ -263,6 +270,12 @@ guest_vaddr2paddr(struct vcpu *vcpu, uint64_t vaddr,
uint64_t *paddr)
return (1);
}
+static uint64_t
+guest_pc(struct vm_exit *vme)
+{
+ return (vme->rip);
+}
+
static void
io_buffer_reset(struct io_buffer *io)
{
@@ -931,7 +944,7 @@ gdb_cpu_breakpoint(struct vcpu *vcpu, struct vm_exit
*vmexit)
}
vcpuid = vcpu_id(vcpu);
pthread_mutex_lock(&gdb_lock);
- error = guest_vaddr2paddr(vcpu, vmexit->rip, &gpa);
+ error = guest_vaddr2paddr(vcpu, guest_pc(vmexit), &gpa);
assert(error == 1);
bp = find_breakpoint(gpa);
if (bp != NULL) {
@@ -940,11 +953,11 @@ gdb_cpu_breakpoint(struct vcpu *vcpu, struct vm_exit
*vmexit)
assert(vs->stepped == false);
assert(vs->hit_swbreak == false);
vs->hit_swbreak = true;
- vm_set_register(vcpu, VM_REG_GUEST_RIP, vmexit->rip);
+ vm_set_register(vcpu, GDB_PC_REGNAME, guest_pc(vmexit));
for (;;) {
if (stopped_vcpu == -1) {
debug("$vCPU %d reporting breakpoint at rip
%#lx\n",
- vcpuid, vmexit->rip);
+ vcpuid, guest_pc(vmexit));
stopped_vcpu = vcpuid;
gdb_suspend_vcpus();
}
@@ -963,7 +976,7 @@ gdb_cpu_breakpoint(struct vcpu *vcpu, struct vm_exit
*vmexit)
gdb_cpu_resume(vcpu);
} else {
debug("$vCPU %d injecting breakpoint at rip %#lx\n", vcpuid,
- vmexit->rip);
+ guest_pc(vmexit));
error = vm_set_register(vcpu, VM_REG_GUEST_ENTRY_INST_LENGTH,
vmexit->u.bpt.inst_length);
assert(error == 0);
@@ -1277,8 +1290,8 @@ remove_all_sw_breakpoints(void)
TAILQ_FOREACH_SAFE(bp, &breakpoints, link, nbp) {
debug("remove breakpoint at %#lx\n", bp->gpa);
- cp = paddr_guest2host(ctx, bp->gpa, 1);
- *cp = bp->shadow_inst;
+ cp = paddr_guest2host(ctx, bp->gpa, sizeof(bp->shadow_inst));
+ memcpy(cp, bp->shadow_inst, sizeof(bp->shadow_inst));
TAILQ_REMOVE(&breakpoints, bp, link);
free(bp);
}
@@ -1294,7 +1307,7 @@ update_sw_breakpoint(uint64_t gva, int kind, bool insert)
uint8_t *cp;
int error;
- if (kind != 1) {
+ if (kind != GDB_BP_SIZE) {
send_error(EINVAL);
return;
}
@@ -1309,7 +1322,7 @@ update_sw_breakpoint(uint64_t gva, int kind, bool insert)
return;
}
- cp = paddr_guest2host(ctx, gpa, 1);
+ cp = paddr_guest2host(ctx, gpa, sizeof(bp->shadow_inst));
/* Only permit breakpoints in guest RAM. */
if (cp == NULL) {
@@ -1333,15 +1346,15 @@ update_sw_breakpoint(uint64_t gva, int kind, bool
insert)
}
bp = malloc(sizeof(*bp));
bp->gpa = gpa;
- bp->shadow_inst = *cp;
- *cp = 0xcc; /* INT 3 */
+ memcpy(bp->shadow_inst, cp, sizeof(bp->shadow_inst));
+ memcpy(cp, GDB_BP_INSTR, sizeof(bp->shadow_inst));
TAILQ_INSERT_TAIL(&breakpoints, bp, link);
debug("new breakpoint at %#lx\n", gpa);
}
} else {
if (bp != NULL) {
debug("remove breakpoint at %#lx\n", gpa);
- *cp = bp->shadow_inst;
+ memcpy(cp, bp->shadow_inst, sizeof(bp->shadow_inst));
TAILQ_REMOVE(&breakpoints, bp, link);
free(bp);
if (TAILQ_EMPTY(&breakpoints))
