git: 596fe0bdc9f6 - stable/14 - bhyve: Prepare to add arm64 support to the gdb stub
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Date: Tue, 30 Jan 2024 14:19:21 UTC
The branch stable/14 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=596fe0bdc9f656c856c597c1b179317a587e7d86 commit 596fe0bdc9f656c856c597c1b179317a587e7d86 Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2024-01-23 16:41:13 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2024-01-30 14:18:55 +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 (cherry picked from commit 5f086566e02a3d21dc840564b90d46f1d3b829bb) --- 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 1b0049c9e6ae..f2976622c79a 100644 --- a/usr.sbin/bhyve/gdb.c +++ b/usr.sbin/bhyve/gdb.c @@ -70,6 +70,13 @@ */ #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); @@ -96,7 +103,7 @@ struct io_buffer { struct breakpoint { uint64_t gpa; - uint8_t shadow_inst; + uint8_t shadow_inst[GDB_BP_SIZE]; TAILQ_ENTRY(breakpoint) link; }; @@ -264,6 +271,12 @@ 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) { @@ -932,7 +945,7 @@ 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) { @@ -941,11 +954,11 @@ 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("$vCPU %d reporting breakpoint at rip %#lx\n", - vcpuid, vmexit->rip); + vcpuid, guest_pc(vmexit)); stopped_vcpu = vcpuid; gdb_suspend_vcpus(); } @@ -964,7 +977,7 @@ gdb_cpu_breakpoint(struct vcpu *vcpu, struct vm_exit *vmexit) gdb_cpu_resume(vcpu); } else { debug("$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); @@ -1278,8 +1291,8 @@ 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); } @@ -1295,7 +1308,7 @@ 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; } @@ -1310,7 +1323,7 @@ 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) { @@ -1334,15 +1347,15 @@ 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))