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[PATCH v2 2/3] hvf: implement guest debugging on Apple Silicon hosts
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From: |
francesco . cagnin |
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Subject: |
[PATCH v2 2/3] hvf: implement guest debugging on Apple Silicon hosts |
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Date: |
Wed, 16 Nov 2022 18:47:48 +0100 |
From: Francesco Cagnin <fcagnin@quarkslab.com>
Support is added for single-stepping, software breakpoints, hardware
breakpoints and watchpoints. The code has been structured like the KVM
counterpart (and many parts are basically identical).
Guests can be debugged through the gdbstub.
Signed-off-by: Francesco Cagnin <fcagnin@quarkslab.com>
---
accel/hvf/hvf-accel-ops.c | 123 ++++++++++++++++++++++++
accel/hvf/hvf-all.c | 24 +++++
cpu.c | 3 +
include/sysemu/hvf.h | 29 ++++++
include/sysemu/hvf_int.h | 1 +
target/arm/hvf/hvf.c | 194 +++++++++++++++++++++++++++++++++++++-
6 files changed, 372 insertions(+), 2 deletions(-)
diff --git a/accel/hvf/hvf-accel-ops.c b/accel/hvf/hvf-accel-ops.c
index 24913ca9c4..1ce0f94a64 100644
--- a/accel/hvf/hvf-accel-ops.c
+++ b/accel/hvf/hvf-accel-ops.c
@@ -52,6 +52,7 @@
#include "qemu/main-loop.h"
#include "exec/address-spaces.h"
#include "exec/exec-all.h"
+#include "exec/gdbstub.h"
#include "sysemu/cpus.h"
#include "sysemu/hvf.h"
#include "sysemu/hvf_int.h"
@@ -340,12 +341,18 @@ static int hvf_accel_init(MachineState *ms)
return hvf_arch_init();
}
+static int hvf_gdbstub_sstep_flags(void)
+{
+ return SSTEP_ENABLE | SSTEP_NOIRQ;
+}
+
static void hvf_accel_class_init(ObjectClass *oc, void *data)
{
AccelClass *ac = ACCEL_CLASS(oc);
ac->name = "HVF";
ac->init_machine = hvf_accel_init;
ac->allowed = &hvf_allowed;
+ ac->gdbstub_supported_sstep_flags = hvf_gdbstub_sstep_flags;
}
static const TypeInfo hvf_accel_type = {
@@ -462,6 +469,117 @@ static void hvf_start_vcpu_thread(CPUState *cpu)
cpu, QEMU_THREAD_JOINABLE);
}
+static bool hvf_supports_guest_debug(void)
+{
+#ifdef TARGET_AARCH64
+ return true;
+#else
+ return false;
+#endif
+}
+
+static int hvf_insert_breakpoint(CPUState *cpu, int type, hwaddr addr, hwaddr
len)
+{
+ struct hvf_sw_breakpoint *bp;
+ int err;
+
+ if (type == GDB_BREAKPOINT_SW) {
+ bp = hvf_find_sw_breakpoint(cpu, addr);
+ if (bp) {
+ bp->use_count++;
+ return 0;
+ }
+
+ bp = g_new(struct hvf_sw_breakpoint, 1);
+ bp->pc = addr;
+ bp->use_count = 1;
+ err = hvf_arch_insert_sw_breakpoint(cpu, bp);
+ if (err) {
+ g_free(bp);
+ return err;
+ }
+
+ QTAILQ_INSERT_HEAD(&cpu->hvf->hvf_sw_breakpoints, bp, entry);
+ } else {
+ err = hvf_arch_insert_hw_breakpoint(addr, len, type);
+ if (err) {
+ return err;
+ }
+ }
+
+ CPU_FOREACH(cpu) {
+ err = hvf_update_guest_debug(cpu);
+ if (err) {
+ return err;
+ }
+ }
+ return 0;
+}
+
+static int hvf_remove_breakpoint(CPUState *cpu, int type, hwaddr addr, hwaddr
len)
+{
+ struct hvf_sw_breakpoint *bp;
+ int err;
+
+ if (type == GDB_BREAKPOINT_SW) {
+ bp = hvf_find_sw_breakpoint(cpu, addr);
+ if (!bp) {
+ return -ENOENT;
+ }
+
+ if (bp->use_count > 1) {
+ bp->use_count--;
+ return 0;
+ }
+
+ err = hvf_arch_remove_sw_breakpoint(cpu, bp);
+ if (err) {
+ return err;
+ }
+
+ QTAILQ_REMOVE(&cpu->hvf->hvf_sw_breakpoints, bp, entry);
+ g_free(bp);
+ } else {
+ err = hvf_arch_remove_hw_breakpoint(addr, len, type);
+ if (err) {
+ return err;
+ }
+ }
+
+ CPU_FOREACH(cpu) {
+ err = hvf_update_guest_debug(cpu);
+ if (err) {
+ return err;
+ }
+ }
+ return 0;
+}
+
+static void hvf_remove_all_breakpoints(CPUState *cpu)
+{
+ struct hvf_sw_breakpoint *bp, *next;
+ CPUState *tmpcpu;
+
+ QTAILQ_FOREACH_SAFE(bp, &cpu->hvf->hvf_sw_breakpoints, entry, next) {
+ if (hvf_arch_remove_sw_breakpoint(cpu, bp) != 0) {
+ /* Try harder to find a CPU that currently sees the breakpoint. */
+ CPU_FOREACH(tmpcpu)
+ {
+ if (hvf_arch_remove_sw_breakpoint(tmpcpu, bp) == 0) {
+ break;
+ }
+ }
+ }
+ QTAILQ_REMOVE(&cpu->hvf->hvf_sw_breakpoints, bp, entry);
+ g_free(bp);
+ }
+ hvf_arch_remove_all_hw_breakpoints();
+
+ CPU_FOREACH(cpu) {
+ hvf_update_guest_debug(cpu);
+ }
+}
+
static void hvf_accel_ops_class_init(ObjectClass *oc, void *data)
{
AccelOpsClass *ops = ACCEL_OPS_CLASS(oc);
@@ -473,6 +591,11 @@ static void hvf_accel_ops_class_init(ObjectClass *oc, void
*data)
ops->synchronize_post_init = hvf_cpu_synchronize_post_init;
ops->synchronize_state = hvf_cpu_synchronize_state;
ops->synchronize_pre_loadvm = hvf_cpu_synchronize_pre_loadvm;
+
+ ops->supports_guest_debug = hvf_supports_guest_debug;
+ ops->insert_breakpoint = hvf_insert_breakpoint;
+ ops->remove_breakpoint = hvf_remove_breakpoint;
+ ops->remove_all_breakpoints = hvf_remove_all_breakpoints;
};
static const TypeInfo hvf_accel_ops_type = {
.name = ACCEL_OPS_NAME("hvf"),
diff --git a/accel/hvf/hvf-all.c b/accel/hvf/hvf-all.c
index 0043f4d308..3f02c090b1 100644
--- a/accel/hvf/hvf-all.c
+++ b/accel/hvf/hvf-all.c
@@ -10,6 +10,7 @@
#include "qemu/osdep.h"
#include "qemu/error-report.h"
+#include "exec/gdbstub.h"
#include "sysemu/hvf.h"
#include "sysemu/hvf_int.h"
@@ -44,3 +45,26 @@ void assert_hvf_ok(hv_return_t ret)
abort();
}
+
+struct hvf_sw_breakpoint *hvf_find_sw_breakpoint(CPUState *cpu, target_ulong
pc)
+{
+ struct hvf_sw_breakpoint *bp;
+
+ QTAILQ_FOREACH(bp, &cpu->hvf->hvf_sw_breakpoints, entry) {
+ if (bp->pc == pc) {
+ return bp;
+ }
+ }
+ return NULL;
+}
+
+int hvf_sw_breakpoints_active(CPUState *cpu)
+{
+ return !QTAILQ_EMPTY(&cpu->hvf->hvf_sw_breakpoints);
+}
+
+int hvf_update_guest_debug(CPUState *cpu)
+{
+ hvf_arch_update_guest_debug(cpu);
+ return 0;
+}
diff --git a/cpu.c b/cpu.c
index 4a7d865427..1fd531aabd 100644
--- a/cpu.c
+++ b/cpu.c
@@ -33,6 +33,7 @@
#endif
#include "sysemu/tcg.h"
#include "sysemu/kvm.h"
+#include "sysemu/hvf.h"
#include "sysemu/replay.h"
#include "exec/cpu-common.h"
#include "exec/exec-all.h"
@@ -389,6 +390,8 @@ void cpu_single_step(CPUState *cpu, int enabled)
cpu->singlestep_enabled = enabled;
if (kvm_enabled()) {
kvm_update_guest_debug(cpu, 0);
+ } else if (hvf_enabled()) {
+ hvf_update_guest_debug(cpu);
}
trace_breakpoint_singlestep(cpu->cpu_index, enabled);
}
diff --git a/include/sysemu/hvf.h b/include/sysemu/hvf.h
index bb70082e45..3e99c80416 100644
--- a/include/sysemu/hvf.h
+++ b/include/sysemu/hvf.h
@@ -36,4 +36,33 @@ typedef struct HVFState HVFState;
DECLARE_INSTANCE_CHECKER(HVFState, HVF_STATE,
TYPE_HVF_ACCEL)
+#ifdef NEED_CPU_H
+#include "cpu.h"
+
+int hvf_update_guest_debug(CPUState *cpu);
+
+struct hvf_sw_breakpoint {
+ target_ulong pc;
+ target_ulong saved_insn;
+ int use_count;
+ QTAILQ_ENTRY(hvf_sw_breakpoint) entry;
+};
+
+struct hvf_sw_breakpoint *hvf_find_sw_breakpoint(CPUState *cpu,
+ target_ulong pc);
+
+int hvf_sw_breakpoints_active(CPUState *cpu);
+
+int hvf_arch_insert_sw_breakpoint(CPUState *cpu, struct hvf_sw_breakpoint *bp);
+int hvf_arch_remove_sw_breakpoint(CPUState *cpu, struct hvf_sw_breakpoint *bp);
+int hvf_arch_insert_hw_breakpoint(target_ulong addr, target_ulong len,
+ int type);
+int hvf_arch_remove_hw_breakpoint(target_ulong addr, target_ulong len,
+ int type);
+void hvf_arch_remove_all_hw_breakpoints(void);
+
+void hvf_arch_update_guest_debug(CPUState *cpu);
+
+#endif /* NEED_CPU_H */
+
#endif
diff --git a/include/sysemu/hvf_int.h b/include/sysemu/hvf_int.h
index 6545f7cd61..a7957d046b 100644
--- a/include/sysemu/hvf_int.h
+++ b/include/sysemu/hvf_int.h
@@ -53,6 +53,7 @@ struct hvf_vcpu_state {
void *exit;
bool vtimer_masked;
sigset_t unblock_ipi_mask;
+ QTAILQ_HEAD(, hvf_sw_breakpoint) hvf_sw_breakpoints;
};
void assert_hvf_ok(hv_return_t ret);
diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
index 060aa0ccf4..66fc82e9b9 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -31,6 +31,22 @@
#include "trace/trace-target_arm_hvf.h"
#include "migration/vmstate.h"
+#include "exec/gdbstub.h"
+
+static void hvf_arm_init_debug(CPUState *cpu)
+{
+ ARMCPU *arm_cpu = ARM_CPU(cpu);
+
+ max_hw_bps = arm_num_brps(arm_cpu);
+ hw_breakpoints =
+ g_array_sized_new(true, true, sizeof(HWBreakpoint), max_hw_bps);
+
+ max_hw_wps = arm_num_wrps(arm_cpu);
+ hw_watchpoints =
+ g_array_sized_new(true, true, sizeof(HWWatchpoint), max_hw_wps);
+ return;
+}
+
#define HVF_SYSREG(crn, crm, op0, op1, op2) \
ENCODE_AA64_CP_REG(CP_REG_ARM64_SYSREG_CP, crn, crm, op0, op1, op2)
#define PL1_WRITE_MASK 0x4
@@ -621,6 +637,8 @@ int hvf_arch_init_vcpu(CPUState *cpu)
&arm_cpu->isar.id_aa64mmfr0);
assert_hvf_ok(ret);
+ hvf_arm_init_debug(cpu);
+
return 0;
}
@@ -1166,11 +1184,12 @@ int hvf_vcpu_exec(CPUState *cpu)
{
ARMCPU *arm_cpu = ARM_CPU(cpu);
CPUARMState *env = &arm_cpu->env;
+ int ret;
hv_vcpu_exit_t *hvf_exit = cpu->hvf->exit;
hv_return_t r;
bool advance_pc = false;
- if (hvf_inject_interrupts(cpu)) {
+ if (!(cpu->singlestep_enabled & SSTEP_NOIRQ) &&
hvf_inject_interrupts(cpu)) {
return EXCP_INTERRUPT;
}
@@ -1188,6 +1207,7 @@ int hvf_vcpu_exec(CPUState *cpu)
uint64_t syndrome = hvf_exit->exception.syndrome;
uint32_t ec = syn_get_ec(syndrome);
+ ret = 0;
qemu_mutex_lock_iothread();
switch (exit_reason) {
case HV_EXIT_REASON_EXCEPTION:
@@ -1207,6 +1227,47 @@ int hvf_vcpu_exec(CPUState *cpu)
hvf_sync_vtimer(cpu);
switch (ec) {
+ case EC_SOFTWARESTEP: {
+ ret = EXCP_DEBUG;
+
+ if (!cpu->singlestep_enabled) {
+ error_report("EC_SOFTWARESTEP but single-stepping not enabled");
+ }
+ break;
+ }
+ case EC_AA64_BKPT: {
+ ret = EXCP_DEBUG;
+
+ cpu_synchronize_state(cpu);
+
+ if (!hvf_find_sw_breakpoint(cpu, env->pc)) {
+ error_report("EC_AA64_BKPT but unknown sw breakpoint");
+ }
+ break;
+ }
+ case EC_BREAKPOINT: {
+ ret = EXCP_DEBUG;
+
+ cpu_synchronize_state(cpu);
+
+ if (!find_hw_breakpoint(cpu, env->pc)) {
+ error_report("EC_BREAKPOINT but unknown hw breakpoint");
+ }
+ break;
+ }
+ case EC_WATCHPOINT: {
+ ret = EXCP_DEBUG;
+
+ cpu_synchronize_state(cpu);
+
+ CPUWatchpoint *wp =
+ find_hw_watchpoint(cpu, hvf_exit->exception.virtual_address);
+ if (!wp) {
+ error_report("EXCP_DEBUG but unknown hw watchpoint");
+ }
+ cpu->watchpoint_hit = wp;
+ break;
+ }
case EC_DATAABORT: {
bool isv = syndrome & ARM_EL_ISV;
bool iswrite = (syndrome >> 6) & 1;
@@ -1313,7 +1374,7 @@ int hvf_vcpu_exec(CPUState *cpu)
assert_hvf_ok(r);
}
- return 0;
+ return ret;
}
static const VMStateDescription vmstate_hvf_vtimer = {
@@ -1347,3 +1408,132 @@ int hvf_arch_init(void)
qemu_add_vm_change_state_handler(hvf_vm_state_change, &vtimer);
return 0;
}
+
+static inline bool hvf_arm_hw_debug_active(CPUState *cpu)
+{
+ return ((cur_hw_wps > 0) || (cur_hw_bps > 0));
+}
+
+static const uint32_t brk_insn = 0xd4200000;
+
+int hvf_arch_insert_sw_breakpoint(CPUState *cpu, struct hvf_sw_breakpoint *bp)
+{
+ if (cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)&bp->saved_insn, 4, 0) ||
+ cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)&brk_insn, 4, 1)) {
+ return -EINVAL;
+ }
+ return 0;
+}
+
+int hvf_arch_remove_sw_breakpoint(CPUState *cpu, struct hvf_sw_breakpoint *bp)
+{
+ static uint32_t brk;
+
+ if (cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)&brk, 4, 0) ||
+ brk != brk_insn ||
+ cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)&bp->saved_insn, 4, 1)) {
+ return -EINVAL;
+ }
+ return 0;
+}
+
+int hvf_arch_insert_hw_breakpoint(target_ulong addr, target_ulong len, int
type)
+{
+ switch (type) {
+ case GDB_BREAKPOINT_HW:
+ return insert_hw_breakpoint(addr);
+ case GDB_WATCHPOINT_READ:
+ case GDB_WATCHPOINT_WRITE:
+ case GDB_WATCHPOINT_ACCESS:
+ return insert_hw_watchpoint(addr, len, type);
+ default:
+ return -ENOSYS;
+ }
+}
+
+int hvf_arch_remove_hw_breakpoint(target_ulong addr, target_ulong len, int
type)
+{
+ switch (type) {
+ case GDB_BREAKPOINT_HW:
+ return delete_hw_breakpoint(addr);
+ case GDB_WATCHPOINT_READ:
+ case GDB_WATCHPOINT_WRITE:
+ case GDB_WATCHPOINT_ACCESS:
+ return delete_hw_watchpoint(addr, len, type);
+ default:
+ return -ENOSYS;
+ }
+}
+
+void hvf_arch_remove_all_hw_breakpoints(void)
+{
+ if (cur_hw_wps > 0) {
+ g_array_remove_range(hw_watchpoints, 0, cur_hw_wps);
+ }
+ if (cur_hw_bps > 0) {
+ g_array_remove_range(hw_breakpoints, 0, cur_hw_bps);
+ }
+}
+
+#define MDSCR_EL1_SS_SHIFT 0
+#define MDSCR_EL1_MDE_SHIFT 15
+
+void hvf_arch_update_guest_debug(CPUState *cpu)
+{
+ ARMCPU *arm_cpu = ARM_CPU(cpu);
+ CPUARMState *env = &arm_cpu->env;
+ hv_return_t r = HV_SUCCESS;
+ bool trap_debug_exceptions = false;
+
+ cpu_synchronize_state(cpu);
+
+ if (cpu->singlestep_enabled) {
+ trap_debug_exceptions = true;
+
+ env->cp15.mdscr_el1 =
+ deposit64(env->cp15.mdscr_el1, MDSCR_EL1_SS_SHIFT, 1, 1);
+ pstate_write(env, pstate_read(env) | PSTATE_SS);
+ } else {
+ env->cp15.mdscr_el1 =
+ deposit64(env->cp15.mdscr_el1, MDSCR_EL1_SS_SHIFT, 1, 0);
+ }
+
+ if (hvf_sw_breakpoints_active(cpu)) {
+ trap_debug_exceptions = true;
+ }
+
+ if (hvf_arm_hw_debug_active(cpu)) {
+ trap_debug_exceptions = true;
+
+ env->cp15.mdscr_el1 =
+ deposit64(env->cp15.mdscr_el1, MDSCR_EL1_MDE_SHIFT, 1, 1);
+
+ int i;
+ for (i = 0; i < cur_hw_bps; i++) {
+ HWBreakpoint *bp = get_hw_bp(i);
+ env->cp15.dbgbcr[i] = bp->bcr;
+ env->cp15.dbgbvr[i] = bp->bvr;
+ }
+ for (i = 0; i < cur_hw_wps; i++) {
+ HWWatchpoint *bp = get_hw_wp(i);
+ env->cp15.dbgwcr[i] = bp->wcr;
+ env->cp15.dbgwvr[i] = bp->wvr;
+ }
+ } else {
+ env->cp15.mdscr_el1 =
+ deposit64(env->cp15.mdscr_el1, MDSCR_EL1_MDE_SHIFT, 1, 0);
+
+ int i;
+ for (i = 0; i < max_hw_bps; i++) {
+ env->cp15.dbgbcr[i] = 0;
+ env->cp15.dbgbvr[i] = 0;
+ }
+ for (i = 0; i < max_hw_wps; i++) {
+ env->cp15.dbgwcr[i] = 0;
+ env->cp15.dbgwvr[i] = 0;
+ }
+ }
+
+ r = hv_vcpu_set_trap_debug_exceptions(cpu->hvf->fd, trap_debug_exceptions);
+ assert_hvf_ok(r);
+}
--
2.38.1