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monitor: Fix crashes when using HMP commands without CPU
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When running certain HMP commands ("info registers", "info cpustats",
"info tlb", "nmi", "memsave" or dumping virtual memory) with the "none"
machine, QEMU crashes with a segmentation fault. This happens because the
"none" machine does not have any CPUs by default, but these HMP commands
did not check for a valid CPU pointer yet. Add such checks now, so we get
an error message about the missing CPU instead.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1484309555-1935-1-git-send-email-thuth@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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@huth @dagrh
huth authored and dagrh committed Feb 21, 2017
1 parent 5fc0048 commit 854e67f
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Showing 7 changed files with 73 additions and 10 deletions.
8 changes: 7 additions & 1 deletion hmp.c
View file
Expand Up @@ -1014,8 +1014,14 @@ void hmp_memsave(Monitor *mon, const QDict *qdict)
const char *filename = qdict_get_str(qdict, "filename");
uint64_t addr = qdict_get_int(qdict, "val");
Error *err = NULL;
int cpu_index = monitor_get_cpu_index();

qmp_memsave(addr, size, filename, true, monitor_get_cpu_index(), &err);
if (cpu_index < 0) {
monitor_printf(mon, "No CPU available\n");
return;
}

qmp_memsave(addr, size, filename, true, cpu_index, &err);
hmp_handle_error(mon, &err);
}

Expand Down
42 changes: 34 additions & 8 deletions monitor.c
View file
Expand Up @@ -1026,6 +1026,9 @@ int monitor_set_cpu(int cpu_index)
CPUState *mon_get_cpu(void)
{
if (!cur_mon->mon_cpu) {
if (!first_cpu) {
return NULL;
}
monitor_set_cpu(first_cpu->cpu_index);
}
cpu_synchronize_state(cur_mon->mon_cpu);
Expand All @@ -1034,17 +1037,27 @@ CPUState *mon_get_cpu(void)

CPUArchState *mon_get_cpu_env(void)
{
return mon_get_cpu()->env_ptr;
CPUState *cs = mon_get_cpu();

return cs ? cs->env_ptr : NULL;
}

int monitor_get_cpu_index(void)
{
return mon_get_cpu()->cpu_index;
CPUState *cs = mon_get_cpu();

return cs ? cs->cpu_index : UNASSIGNED_CPU_INDEX;
}

static void hmp_info_registers(Monitor *mon, const QDict *qdict)
{
cpu_dump_state(mon_get_cpu(), (FILE *)mon, monitor_fprintf, CPU_DUMP_FPU);
CPUState *cs = mon_get_cpu();

if (!cs) {
monitor_printf(mon, "No CPU available\n");
return;
}
cpu_dump_state(cs, (FILE *)mon, monitor_fprintf, CPU_DUMP_FPU);
}

static void hmp_info_jit(Monitor *mon, const QDict *qdict)
Expand Down Expand Up @@ -1077,7 +1090,13 @@ static void hmp_info_history(Monitor *mon, const QDict *qdict)

static void hmp_info_cpustats(Monitor *mon, const QDict *qdict)
{
cpu_dump_statistics(mon_get_cpu(), (FILE *)mon, &monitor_fprintf, 0);
CPUState *cs = mon_get_cpu();

if (!cs) {
monitor_printf(mon, "No CPU available\n");
return;
}
cpu_dump_statistics(cs, (FILE *)mon, &monitor_fprintf, 0);
}

static void hmp_info_trace_events(Monitor *mon, const QDict *qdict)
Expand Down Expand Up @@ -1236,6 +1255,12 @@ static void memory_dump(Monitor *mon, int count, int format, int wsize,
int l, line_size, i, max_digits, len;
uint8_t buf[16];
uint64_t v;
CPUState *cs = mon_get_cpu();

if (!cs && (format == 'i' || !is_physical)) {
monitor_printf(mon, "Can not dump without CPU\n");
return;
}

if (format == 'i') {
int flags = 0;
Expand Down Expand Up @@ -1265,7 +1290,7 @@ static void memory_dump(Monitor *mon, int count, int format, int wsize,
flags = msr_le << 16;
flags |= env->bfd_mach;
#endif
monitor_disas(mon, mon_get_cpu(), addr, count, is_physical, flags);
monitor_disas(mon, cs, addr, count, is_physical, flags);
return;
}

Expand Down Expand Up @@ -1304,7 +1329,7 @@ static void memory_dump(Monitor *mon, int count, int format, int wsize,
if (is_physical) {
cpu_physical_memory_read(addr, buf, l);
} else {
if (cpu_memory_rw_debug(mon_get_cpu(), addr, buf, l, 0) < 0) {
if (cpu_memory_rw_debug(cs, addr, buf, l, 0) < 0) {
monitor_printf(mon, " Cannot access memory\n");
break;
}
Expand Down Expand Up @@ -2189,11 +2214,12 @@ expr_error(Monitor *mon, const char *fmt, ...)
static int get_monitor_def(target_long *pval, const char *name)
{
const MonitorDef *md = target_monitor_defs();
CPUState *cs = mon_get_cpu();
void *ptr;
uint64_t tmp = 0;
int ret;

if (md == NULL) {
if (cs == NULL || md == NULL) {
return -1;
}

Expand All @@ -2220,7 +2246,7 @@ static int get_monitor_def(target_long *pval, const char *name)
}
}

ret = target_get_monitor_def(mon_get_cpu(), name, &tmp);
ret = target_get_monitor_def(cs, name, &tmp);
if (!ret) {
*pval = (target_long) tmp;
}
Expand Down
16 changes: 15 additions & 1 deletion target/i386/monitor.c
View file
Expand Up @@ -210,6 +210,10 @@ void hmp_info_tlb(Monitor *mon, const QDict *qdict)
CPUArchState *env;

env = mon_get_cpu_env();
if (!env) {
monitor_printf(mon, "No CPU available\n");
return;
}

if (!(env->cr[0] & CR0_PG_MASK)) {
monitor_printf(mon, "PG disabled\n");
Expand Down Expand Up @@ -529,6 +533,10 @@ void hmp_info_mem(Monitor *mon, const QDict *qdict)
CPUArchState *env;

env = mon_get_cpu_env();
if (!env) {
monitor_printf(mon, "No CPU available\n");
return;
}

if (!(env->cr[0] & CR0_PG_MASK)) {
monitor_printf(mon, "PG disabled\n");
Expand Down Expand Up @@ -624,7 +632,13 @@ const MonitorDef *target_monitor_defs(void)

void hmp_info_local_apic(Monitor *mon, const QDict *qdict)
{
x86_cpu_dump_local_apic_state(mon_get_cpu(), (FILE *)mon, monitor_fprintf,
CPUState *cs = mon_get_cpu();

if (!cs) {
monitor_printf(mon, "No CPU available\n");
return;
}
x86_cpu_dump_local_apic_state(cs, (FILE *)mon, monitor_fprintf,
CPU_DUMP_FPU);
}

Expand Down
4 changes: 4 additions & 0 deletions target/ppc/monitor.c
View file
Expand Up @@ -62,6 +62,10 @@ void hmp_info_tlb(Monitor *mon, const QDict *qdict)
{
CPUArchState *env1 = mon_get_cpu_env();

if (!env1) {
monitor_printf(mon, "No CPU available\n");
return;
}
dump_mmu((FILE*)mon, (fprintf_function)monitor_printf, env1);
}

Expand Down
5 changes: 5 additions & 0 deletions target/sh4/monitor.c
View file
Expand Up @@ -44,6 +44,11 @@ void hmp_info_tlb(Monitor *mon, const QDict *qdict)
CPUArchState *env = mon_get_cpu_env();
int i;

if (!env) {
monitor_printf(mon, "No CPU available\n");
return;
}

monitor_printf (mon, "ITLB:\n");
for (i = 0 ; i < ITLB_SIZE ; i++)
print_tlb (mon, i, &env->itlb[i]);
Expand Down
4 changes: 4 additions & 0 deletions target/sparc/monitor.c
View file
Expand Up @@ -32,6 +32,10 @@ void hmp_info_tlb(Monitor *mon, const QDict *qdict)
{
CPUArchState *env1 = mon_get_cpu_env();

if (!env1) {
monitor_printf(mon, "No CPU available\n");
return;
}
dump_mmu((FILE*)mon, (fprintf_function)monitor_printf, env1);
}

Expand Down
4 changes: 4 additions & 0 deletions target/xtensa/monitor.c
View file
Expand Up @@ -31,5 +31,9 @@ void hmp_info_tlb(Monitor *mon, const QDict *qdict)
{
CPUArchState *env1 = mon_get_cpu_env();

if (!env1) {
monitor_printf(mon, "No CPU available\n");
return;
}
dump_mmu((FILE*)mon, (fprintf_function)monitor_printf, env1);
}

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