git: a0ca4af9455b - main - bhyve: Add arm64 support to the gdb stub
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Date: Tue, 04 Jun 2024 20:06:31 UTC
The branch main has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=a0ca4af9455b844c5e094fc1b09b1390ffa979fc
commit a0ca4af9455b844c5e094fc1b09b1390ffa979fc
Author: Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2024-06-04 19:03:17 +0000
Commit: Mark Johnston <markj@FreeBSD.org>
CommitDate: 2024-06-04 19:03:17 +0000
bhyve: Add arm64 support to the gdb stub
- Add -G to the arm64 getopt handler.
- Add static register definitions and extensible XML definitions.
- Provide definitions for MD bits such as breakpoint encoding and
length.
- Ensure that bhyve re-injects breakpoint exceptions that it is not
responsible for.
Reviewed by: andrew
Sponsored by: Innovate UK
Differential Revision: https://reviews.freebsd.org/D44740
---
usr.sbin/bhyve/aarch64/Makefile.inc | 1 +
usr.sbin/bhyve/aarch64/bhyverun_machdep.c | 6 +-
usr.sbin/bhyve/aarch64/vmexit.c | 20 +++-
usr.sbin/bhyve/gdb.c | 151 +++++++++++++++++++++++++++---
usr.sbin/bhyve/gdb/Makefile | 3 +
usr.sbin/bhyve/gdb/aarch64-core.xml | 46 +++++++++
6 files changed, 213 insertions(+), 14 deletions(-)
diff --git a/usr.sbin/bhyve/aarch64/Makefile.inc b/usr.sbin/bhyve/aarch64/Makefile.inc
index e2ea4414ca19..af458e719d44 100644
--- a/usr.sbin/bhyve/aarch64/Makefile.inc
+++ b/usr.sbin/bhyve/aarch64/Makefile.inc
@@ -7,3 +7,4 @@ SRCS+= \
SRCS+= vmm_instruction_emul.c
BHYVE_FDT_SUPPORT=
+BHYVE_GDB_SUPPORT=
diff --git a/usr.sbin/bhyve/aarch64/bhyverun_machdep.c b/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
index a5fd3f054706..fbaba3128def 100644
--- a/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
+++ b/usr.sbin/bhyve/aarch64/bhyverun_machdep.c
@@ -99,6 +99,7 @@ bhyve_usage(int code)
" -C: include guest memory in core file\n"
" -c: number of CPUs and/or topology specification\n"
" -D: destroy on power-off\n"
+ " -G: start a debug server\n"
" -h: help\n"
" -k: key=value flat config file\n"
" -m: memory size\n"
@@ -119,7 +120,7 @@ bhyve_optparse(int argc, char **argv)
const char *optstr;
int c;
- optstr = "hCDSWk:f:o:p:c:s:m:U:";
+ optstr = "hCDSWk:f:o:p:G:c:s:m:U:";
while ((c = getopt(argc, argv, optstr)) != -1) {
switch (c) {
case 'c':
@@ -134,6 +135,9 @@ bhyve_optparse(int argc, char **argv)
case 'D':
set_config_bool("destroy_on_poweroff", true);
break;
+ case 'G':
+ bhyve_parse_gdb_options(optarg);
+ break;
case 'k':
bhyve_parse_simple_config_file(optarg);
break;
diff --git a/usr.sbin/bhyve/aarch64/vmexit.c b/usr.sbin/bhyve/aarch64/vmexit.c
index 0d328ab4ff85..03fc2f8b21e3 100644
--- a/usr.sbin/bhyve/aarch64/vmexit.c
+++ b/usr.sbin/bhyve/aarch64/vmexit.c
@@ -49,6 +49,7 @@
#include "bhyverun.h"
#include "config.h"
#include "debug.h"
+#include "gdb.h"
#include "mem.h"
#include "vmexit.h"
@@ -112,9 +113,10 @@ vmexit_suspend(struct vmctx *ctx, struct vcpu *vcpu, struct vm_run *vmrun)
}
static int
-vmexit_debug(struct vmctx *ctx __unused, struct vcpu *vcpu __unused,
+vmexit_debug(struct vmctx *ctx __unused, struct vcpu *vcpu,
struct vm_run *vmrun __unused)
{
+ gdb_cpu_suspend(vcpu);
return (VMEXIT_CONTINUE);
}
@@ -250,6 +252,20 @@ vmexit_hyp(struct vmctx *ctx __unused, struct vcpu *vcpu __unused,
return (VMEXIT_ABORT);
}
+static int
+vmexit_brk(struct vmctx *ctx __unused, struct vcpu *vcpu, struct vm_run *vmrun)
+{
+ gdb_cpu_breakpoint(vcpu, vmrun->vm_exit);
+ return (VMEXIT_CONTINUE);
+}
+
+static int
+vmexit_ss(struct vmctx *ctx __unused, struct vcpu *vcpu, struct vm_run *vmrun)
+{
+ gdb_cpu_debug(vcpu, vmrun->vm_exit);
+ return (VMEXIT_CONTINUE);
+}
+
const vmexit_handler_t vmexit_handlers[VM_EXITCODE_MAX] = {
[VM_EXITCODE_BOGUS] = vmexit_bogus,
[VM_EXITCODE_INST_EMUL] = vmexit_inst_emul,
@@ -257,4 +273,6 @@ const vmexit_handler_t vmexit_handlers[VM_EXITCODE_MAX] = {
[VM_EXITCODE_DEBUG] = vmexit_debug,
[VM_EXITCODE_SMCCC] = vmexit_smccc,
[VM_EXITCODE_HYP] = vmexit_hyp,
+ [VM_EXITCODE_BRK] = vmexit_brk,
+ [VM_EXITCODE_SS] = vmexit_ss,
};
diff --git a/usr.sbin/bhyve/gdb.c b/usr.sbin/bhyve/gdb.c
index 479ad407dbef..6df8026a0245 100644
--- a/usr.sbin/bhyve/gdb.c
+++ b/usr.sbin/bhyve/gdb.c
@@ -36,10 +36,17 @@
#include <sys/socket.h>
#include <sys/stat.h>
+#ifdef __aarch64__
+#include <machine/armreg.h>
+#endif
#include <machine/atomic.h>
+#ifdef __amd64__
#include <machine/specialreg.h>
+#endif
#include <machine/vmm.h>
+
#include <netinet/in.h>
+
#include <assert.h>
#ifndef WITHOUT_CAPSICUM
#include <capsicum_helpers.h>
@@ -73,9 +80,19 @@
*/
#define GDB_SIGNAL_TRAP 5
+#if defined(__amd64__)
#define GDB_BP_SIZE 1
#define GDB_BP_INSTR (uint8_t []){0xcc}
#define GDB_PC_REGNAME VM_REG_GUEST_RIP
+#define GDB_BREAKPOINT_CAP VM_CAP_BPT_EXIT
+#elif defined(__aarch64__)
+#define GDB_BP_SIZE 4
+#define GDB_BP_INSTR (uint8_t []){0x00, 0x00, 0x20, 0xd4}
+#define GDB_PC_REGNAME VM_REG_GUEST_PC
+#define GDB_BREAKPOINT_CAP VM_CAP_BRK_EXIT
+#else
+#error "Unsupported architecture"
+#endif
_Static_assert(sizeof(GDB_BP_INSTR) == GDB_BP_SIZE,
"GDB_BP_INSTR has wrong size");
@@ -146,10 +163,13 @@ static struct vcpu **vcpus;
static int cur_vcpu, stopped_vcpu;
static bool gdb_active = false;
-static const struct gdb_reg {
+struct gdb_reg {
enum vm_reg_name id;
int size;
-} gdb_regset[] = {
+}
+
+#ifdef __amd64__
+static const gdb_regset[] = {
{ .id = VM_REG_GUEST_RAX, .size = 8 },
{ .id = VM_REG_GUEST_RBX, .size = 8 },
{ .id = VM_REG_GUEST_RCX, .size = 8 },
@@ -191,6 +211,44 @@ static const struct gdb_reg {
{ .id = VM_REG_GUEST_TPR, .size = 8 },
{ .id = VM_REG_GUEST_EFER, .size = 8 },
};
+#else /* __aarch64__ */
+static const gdb_regset[] = {
+ { .id = VM_REG_GUEST_X0, .size = 8 },
+ { .id = VM_REG_GUEST_X1, .size = 8 },
+ { .id = VM_REG_GUEST_X2, .size = 8 },
+ { .id = VM_REG_GUEST_X3, .size = 8 },
+ { .id = VM_REG_GUEST_X4, .size = 8 },
+ { .id = VM_REG_GUEST_X5, .size = 8 },
+ { .id = VM_REG_GUEST_X6, .size = 8 },
+ { .id = VM_REG_GUEST_X7, .size = 8 },
+ { .id = VM_REG_GUEST_X8, .size = 8 },
+ { .id = VM_REG_GUEST_X9, .size = 8 },
+ { .id = VM_REG_GUEST_X10, .size = 8 },
+ { .id = VM_REG_GUEST_X11, .size = 8 },
+ { .id = VM_REG_GUEST_X12, .size = 8 },
+ { .id = VM_REG_GUEST_X13, .size = 8 },
+ { .id = VM_REG_GUEST_X14, .size = 8 },
+ { .id = VM_REG_GUEST_X15, .size = 8 },
+ { .id = VM_REG_GUEST_X16, .size = 8 },
+ { .id = VM_REG_GUEST_X17, .size = 8 },
+ { .id = VM_REG_GUEST_X18, .size = 8 },
+ { .id = VM_REG_GUEST_X19, .size = 8 },
+ { .id = VM_REG_GUEST_X20, .size = 8 },
+ { .id = VM_REG_GUEST_X21, .size = 8 },
+ { .id = VM_REG_GUEST_X22, .size = 8 },
+ { .id = VM_REG_GUEST_X23, .size = 8 },
+ { .id = VM_REG_GUEST_X24, .size = 8 },
+ { .id = VM_REG_GUEST_X25, .size = 8 },
+ { .id = VM_REG_GUEST_X26, .size = 8 },
+ { .id = VM_REG_GUEST_X27, .size = 8 },
+ { .id = VM_REG_GUEST_X28, .size = 8 },
+ { .id = VM_REG_GUEST_X29, .size = 8 },
+ { .id = VM_REG_GUEST_LR, .size = 8 },
+ { .id = VM_REG_GUEST_SP, .size = 8 },
+ { .id = VM_REG_GUEST_PC, .size = 8 },
+ { .id = VM_REG_GUEST_CPSR, .size = 8 },
+};
+#endif
#ifdef GDB_LOG
#include <stdarg.h>
@@ -228,6 +286,7 @@ static void remove_all_sw_breakpoints(void);
static int
guest_paging_info(struct vcpu *vcpu, struct vm_guest_paging *paging)
{
+#ifdef __amd64__
uint64_t regs[4];
const int regset[4] = {
VM_REG_GUEST_CR0,
@@ -262,6 +321,31 @@ guest_paging_info(struct vcpu *vcpu, struct vm_guest_paging *paging)
else
paging->paging_mode = PAGING_MODE_PAE;
return (0);
+#else /* __aarch64__ */
+ uint64_t regs[6];
+ const int regset[6] = {
+ VM_REG_GUEST_TTBR0_EL1,
+ VM_REG_GUEST_TTBR1_EL1,
+ VM_REG_GUEST_TCR_EL1,
+ VM_REG_GUEST_TCR2_EL1,
+ VM_REG_GUEST_SCTLR_EL1,
+ VM_REG_GUEST_CPSR,
+ };
+
+ if (vm_get_register_set(vcpu, nitems(regset), regset, regs) == -1)
+ return (-1);
+
+ memset(paging, 0, sizeof(*paging));
+ paging->ttbr0_addr = regs[0] & ~(TTBR_ASID_MASK | TTBR_CnP);
+ paging->ttbr1_addr = regs[1] & ~(TTBR_ASID_MASK | TTBR_CnP);
+ paging->tcr_el1 = regs[2];
+ paging->tcr2_el1 = regs[3];
+ paging->flags = regs[5] & (PSR_M_MASK | PSR_M_32);
+ if ((regs[4] & SCTLR_M) != 0)
+ paging->flags |= VM_GP_MMU_ENABLED;
+
+ return (0);
+#endif /* __aarch64__ */
}
/*
@@ -294,7 +378,11 @@ guest_vaddr2paddr(struct vcpu *vcpu, uint64_t vaddr, uint64_t *paddr)
static uint64_t
guest_pc(struct vm_exit *vme)
{
+#ifdef __amd64__
return (vme->rip);
+#else /* __aarch64__ */
+ return (vme->pc);
+#endif
}
static void
@@ -762,6 +850,7 @@ _gdb_set_step(struct vcpu *vcpu, int val)
{
int error;
+#ifdef __amd64__
/*
* If the MTRAP cap fails, we are running on an AMD host.
* In that case, we request DB exits caused by RFLAGS.TF.
@@ -771,23 +860,31 @@ _gdb_set_step(struct vcpu *vcpu, int val)
error = vm_set_capability(vcpu, VM_CAP_RFLAGS_TF, val);
if (error == 0)
(void)vm_set_capability(vcpu, VM_CAP_MASK_HWINTR, val);
-
+#else /* __aarch64__ */
+ error = vm_set_capability(vcpu, VM_CAP_SS_EXIT, val);
+ if (error == 0)
+ error = vm_set_capability(vcpu, VM_CAP_MASK_HWINTR, val);
+#endif
return (error);
}
/*
- * Checks whether single-stepping is enabled for a given vCPU.
+ * Checks whether single-stepping is supported for a given vCPU.
*/
static int
_gdb_check_step(struct vcpu *vcpu)
{
+#ifdef __amd64__
int val;
if (vm_get_capability(vcpu, VM_CAP_MTRAP_EXIT, &val) != 0) {
if (vm_get_capability(vcpu, VM_CAP_RFLAGS_TF, &val) != 0)
- return -1;
+ return (-1);
}
- return 0;
+#else /* __aarch64__ */
+ (void)vcpu;
+#endif
+ return (0);
}
/*
@@ -809,7 +906,7 @@ gdb_cpu_add(struct vcpu *vcpu)
vcpus[vcpuid] = vcpu;
CPU_SET(vcpuid, &vcpus_active);
if (!TAILQ_EMPTY(&breakpoints)) {
- vm_set_capability(vcpu, VM_CAP_BPT_EXIT, 1);
+ vm_set_capability(vcpu, GDB_BREAKPOINT_CAP, 1);
debug("$vCPU %d enabled breakpoint exits\n", vcpuid);
}
@@ -912,7 +1009,7 @@ gdb_cpu_step(struct vcpu *vcpu)
}
/*
- * A general handler for VM_EXITCODE_DB.
+ * A general handler for single-step exceptions.
* Handles RFLAGS.TF exits on AMD SVM.
*/
void
@@ -921,10 +1018,15 @@ gdb_cpu_debug(struct vcpu *vcpu, struct vm_exit *vmexit)
if (!gdb_active)
return;
+#ifdef __amd64__
/* RFLAGS.TF exit? */
if (vmexit->u.dbg.trace_trap) {
gdb_cpu_step(vcpu);
}
+#else /* __aarch64__ */
+ (void)vmexit;
+ gdb_cpu_step(vcpu);
+#endif
}
/*
@@ -998,11 +1100,19 @@ gdb_cpu_breakpoint(struct vcpu *vcpu, struct vm_exit *vmexit)
} else {
debug("$vCPU %d injecting breakpoint at rip %#lx\n", vcpuid,
guest_pc(vmexit));
+#ifdef __amd64__
error = vm_set_register(vcpu, VM_REG_GUEST_ENTRY_INST_LENGTH,
vmexit->u.bpt.inst_length);
assert(error == 0);
error = vm_inject_exception(vcpu, IDT_BP, 0, 0, 0);
assert(error == 0);
+#else /* __aarch64__ */
+ uint64_t esr;
+
+ esr = (EXCP_BRK << ESR_ELx_EC_SHIFT) | vmexit->u.hyp.esr_el2;
+ error = vm_inject_exception(vcpu, esr, 0);
+ assert(error == 0);
+#endif
}
pthread_mutex_unlock(&gdb_lock);
}
@@ -1053,8 +1163,10 @@ gdb_read_regs(void)
start_packet();
for (size_t i = 0; i < nitems(gdb_regset); i++) {
+#ifdef GDB_REG_FIRST_EXT
if (gdb_regset[i].id == GDB_REG_FIRST_EXT)
break;
+#endif
append_unsigned_native(regvals[i], gdb_regset[i].size);
}
finish_packet();
@@ -1318,7 +1430,7 @@ set_breakpoint_caps(bool enable)
while (!CPU_EMPTY(&mask)) {
vcpu = CPU_FFS(&mask) - 1;
CPU_CLR(vcpu, &mask);
- if (vm_set_capability(vcpus[vcpu], VM_CAP_BPT_EXIT,
+ if (vm_set_capability(vcpus[vcpu], GDB_BREAKPOINT_CAP,
enable ? 1 : 0) < 0)
return (false);
debug("$vCPU %d %sabled breakpoint exits\n", vcpu,
@@ -1327,6 +1439,20 @@ set_breakpoint_caps(bool enable)
return (true);
}
+static void
+write_instr(uint8_t *dest, uint8_t *instr, size_t len)
+{
+ memcpy(dest, instr, len);
+#ifdef __arm64__
+ __asm __volatile(
+ "dc cvau, %0\n"
+ "dsb ish\n"
+ "ic ialluis\n"
+ "dsb ish\n"
+ : : "r" (dest) : "memory");
+#endif
+}
+
static void
remove_all_sw_breakpoints(void)
{
@@ -1339,7 +1465,7 @@ 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, sizeof(bp->shadow_inst));
- memcpy(cp, bp->shadow_inst, sizeof(bp->shadow_inst));
+ write_instr(cp, bp->shadow_inst, sizeof(bp->shadow_inst));
TAILQ_REMOVE(&breakpoints, bp, link);
free(bp);
}
@@ -1395,14 +1521,15 @@ update_sw_breakpoint(uint64_t gva, int kind, bool insert)
bp = malloc(sizeof(*bp));
bp->gpa = gpa;
memcpy(bp->shadow_inst, cp, sizeof(bp->shadow_inst));
- memcpy(cp, GDB_BP_INSTR, sizeof(bp->shadow_inst));
+ write_instr(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);
- memcpy(cp, bp->shadow_inst, sizeof(bp->shadow_inst));
+ write_instr(cp, bp->shadow_inst,
+ sizeof(bp->shadow_inst));
TAILQ_REMOVE(&breakpoints, bp, link);
free(bp);
if (TAILQ_EMPTY(&breakpoints))
diff --git a/usr.sbin/bhyve/gdb/Makefile b/usr.sbin/bhyve/gdb/Makefile
index cc9ba4d224da..d9edbe02aea4 100644
--- a/usr.sbin/bhyve/gdb/Makefile
+++ b/usr.sbin/bhyve/gdb/Makefile
@@ -6,6 +6,9 @@ FILES+= target.xml
.if ${MACHINE_ARCH} == "amd64"
XMLARCH= i386:x86-64
FILES+= amd64.xml
+.elif ${MACHINE_ARCH} == "aarch64"
+XMLARCH= aarch64
+FILES+= aarch64-core.xml
.endif
.if !make(install*)
diff --git a/usr.sbin/bhyve/gdb/aarch64-core.xml b/usr.sbin/bhyve/gdb/aarch64-core.xml
new file mode 100644
index 000000000000..c44b679405b7
--- /dev/null
+++ b/usr.sbin/bhyve/gdb/aarch64-core.xml
@@ -0,0 +1,46 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2009-2012 Free Software Foundation, Inc.
+ Contributed by ARM Ltd.
+
+ Copying and distribution of this file, with or without modification,
+ are permitted in any medium without royalty provided the copyright
+ notice and this notice are preserved. -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.aarch64.core">
+ <reg name="x0" bitsize="64"/>
+ <reg name="x1" bitsize="64"/>
+ <reg name="x2" bitsize="64"/>
+ <reg name="x3" bitsize="64"/>
+ <reg name="x4" bitsize="64"/>
+ <reg name="x5" bitsize="64"/>
+ <reg name="x6" bitsize="64"/>
+ <reg name="x7" bitsize="64"/>
+ <reg name="x8" bitsize="64"/>
+ <reg name="x9" bitsize="64"/>
+ <reg name="x10" bitsize="64"/>
+ <reg name="x11" bitsize="64"/>
+ <reg name="x12" bitsize="64"/>
+ <reg name="x13" bitsize="64"/>
+ <reg name="x14" bitsize="64"/>
+ <reg name="x15" bitsize="64"/>
+ <reg name="x16" bitsize="64"/>
+ <reg name="x17" bitsize="64"/>
+ <reg name="x18" bitsize="64"/>
+ <reg name="x19" bitsize="64"/>
+ <reg name="x20" bitsize="64"/>
+ <reg name="x21" bitsize="64"/>
+ <reg name="x22" bitsize="64"/>
+ <reg name="x23" bitsize="64"/>
+ <reg name="x24" bitsize="64"/>
+ <reg name="x25" bitsize="64"/>
+ <reg name="x26" bitsize="64"/>
+ <reg name="x27" bitsize="64"/>
+ <reg name="x28" bitsize="64"/>
+ <reg name="x29" bitsize="64"/>
+ <reg name="x30" bitsize="64"/>
+ <reg name="sp" bitsize="64" type="data_ptr"/>
+
+ <reg name="pc" bitsize="64" type="code_ptr"/>
+ <reg name="cpsr" bitsize="64"/>
+</feature>