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hvf: add breakpoint handlers 
Required for guest debugging. The code has been structured like the KVM
counterpart.

Signed-off-by: Francesco Cagnin <fcagnin@quarkslab.com>
Message-id: 20230601153107.81955-4-fcagnin@quarkslab.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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@integeruser @pm215
integeruser authored and pm215 committed Jun 6, 2023
1 parent ce799a0 commit f415204
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Showing 6 changed files with 236 additions and 0 deletions.
109 changes: 109 additions & 0 deletions accel/hvf/hvf-accel-ops.c
View file
Expand Up @@ -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"
Expand Down Expand Up @@ -334,6 +335,8 @@ static int hvf_accel_init(MachineState *ms)
s->slots[x].slot_id = x;
}

QTAILQ_INIT(&s->hvf_sw_breakpoints);

hvf_state = s;
memory_listener_register(&hvf_memory_listener, &address_space_memory);

Expand Down Expand Up @@ -462,6 +465,108 @@ static void hvf_start_vcpu_thread(CPUState *cpu)
cpu, QEMU_THREAD_JOINABLE);
}

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(&hvf_state->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(&hvf_state->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, &hvf_state->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(&hvf_state->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);
Expand All @@ -473,6 +578,10 @@ 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->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"),
Expand Down
17 changes: 17 additions & 0 deletions accel/hvf/hvf-all.c
View file
Expand Up @@ -44,3 +44,20 @@ 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, &hvf_state->hvf_sw_breakpoints, entry) {
if (bp->pc == pc) {
return bp;
}
}
return NULL;
}

int hvf_sw_breakpoints_active(CPUState *cpu)
{
return !QTAILQ_EMPTY(&hvf_state->hvf_sw_breakpoints);
}
22 changes: 22 additions & 0 deletions include/sysemu/hvf.h
View file
Expand Up @@ -17,6 +17,7 @@
#include "qom/object.h"

#ifdef NEED_CPU_H
#include "cpu.h"

#ifdef CONFIG_HVF
uint32_t hvf_get_supported_cpuid(uint32_t func, uint32_t idx,
Expand All @@ -36,4 +37,25 @@ typedef struct HVFState HVFState;
DECLARE_INSTANCE_CHECKER(HVFState, HVF_STATE,
TYPE_HVF_ACCEL)

#ifdef NEED_CPU_H
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);
#endif /* NEED_CPU_H */

#endif
1 change: 1 addition & 0 deletions include/sysemu/hvf_int.h
View file
Expand Up @@ -45,6 +45,7 @@ struct HVFState {

hvf_vcpu_caps *hvf_caps;
uint64_t vtimer_offset;
QTAILQ_HEAD(, hvf_sw_breakpoint) hvf_sw_breakpoints;
};
extern HVFState *hvf_state;

Expand Down
63 changes: 63 additions & 0 deletions target/arm/hvf/hvf.c
View file
Expand Up @@ -31,6 +31,8 @@
#include "trace/trace-target_arm_hvf.h"
#include "migration/vmstate.h"

#include "exec/gdbstub.h"

#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
Expand Down Expand Up @@ -1711,3 +1713,64 @@ int hvf_arch_init(void)
qemu_add_vm_change_state_handler(hvf_vm_state_change, &vtimer);
return 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);
}
}
24 changes: 24 additions & 0 deletions target/i386/hvf/hvf.c
View file
Expand Up @@ -679,3 +679,27 @@ int hvf_vcpu_exec(CPUState *cpu)

return ret;
}

int hvf_arch_insert_sw_breakpoint(CPUState *cpu, struct hvf_sw_breakpoint *bp)
{
return -ENOSYS;
}

int hvf_arch_remove_sw_breakpoint(CPUState *cpu, struct hvf_sw_breakpoint *bp)
{
return -ENOSYS;
}

int hvf_arch_insert_hw_breakpoint(target_ulong addr, target_ulong len, int type)
{
return -ENOSYS;
}

int hvf_arch_remove_hw_breakpoint(target_ulong addr, target_ulong len, int type)
{
return -ENOSYS;
}

void hvf_arch_remove_all_hw_breakpoints(void)
{
}

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