Paolo Bonzini <pbonz...@redhat.com> writes:
> From: Claudio Imbrenda <imbre...@linux.vnet.ibm.com>
>
> When GDB issues a "vCont", QEMU was not handling it correctly when
> multiple VCPUs are active.
> For vCont, for each thread (VCPU), it can be specified whether to
> single step, continue or stop that thread. The default is to stop a
> thread.
<snip>
>
> +/**
> + * gdb_handle_vcont - Parses and handles a vCont packet.
> + * returns -ENOTSUP if a command is unsupported, -EINVAL or -ERANGE if there
> is
> + * a format error, 0 on success.
> + */
> +static int gdb_handle_vcont(GDBState *s, const char *p)
> +{
> + int res, idx, signal = 0;
> + char cur_action;
> + char *newstates;
> + unsigned long tmp;
> + CPUState *cpu;
> +#ifdef CONFIG_USER_ONLY
> + int max_cpus = 1; /* global variable max_cpus exists only in system mode
> */
> +
> + CPU_FOREACH(cpu) {
> + max_cpus = max_cpus <= cpu->cpu_index ? cpu->cpu_index + 1 :
> max_cpus;
> + }
> +#endif
> + /* uninitialised CPUs stay 0 */
> + newstates = g_new0(char, max_cpus);
> +
> + /* mark valid CPUs with 1 */
> + CPU_FOREACH(cpu) {
> + newstates[cpu->cpu_index] = 1;
> + }
> +
> + /*
> + * res keeps track of what error we are returning, with -ENOTSUP meaning
> + * that the command is unknown or unsupported, thus returning an empty
> + * packet, while -EINVAL and -ERANGE cause an E22 packet, due to invalid,
> + * or incorrect parameters passed.
> + */
> + res = 0;
> + while (*p) {
> + if (*p++ != ';') {
> + res = -ENOTSUP;
> + goto out;
> + }
> +
> + cur_action = *p++;
> + if (cur_action == 'C' || cur_action == 'S') {
> + cur_action = tolower(cur_action);
> + res = qemu_strtoul(p + 1, &p, 16, &tmp);
> + if (res) {
> + goto out;
> + }
> + signal = gdb_signal_to_target(tmp);
> + } else if (cur_action != 'c' && cur_action != 's') {
> + /* unknown/invalid/unsupported command */
> + res = -ENOTSUP;
> + goto out;
> + }
> + /* thread specification. special values: (none), -1 = all; 0 = any */
> + if ((p[0] == ':' && p[1] == '-' && p[2] == '1') || (p[0] != ':')) {
> + if (*p == ':') {
> + p += 3;
> + }
> + for (idx = 0; idx < max_cpus; idx++) {
> + if (newstates[idx] == 1) {
> + newstates[idx] = cur_action;
> + }
> + }
> + } else if (*p == ':') {
> + p++;
> + res = qemu_strtoul(p, &p, 16, &tmp);
> + if (res) {
> + goto out;
> + }
> + idx = tmp;
> + /* 0 means any thread, so we pick the first valid CPU */
> + if (!idx) {
> + idx = cpu_index(first_cpu);
> + }
> +
> + /*
> + * If we are in user mode, the thread specified is actually a
> + * thread id, and not an index. We need to find the actual
> + * CPU first, and only then we can use its index.
> + */
> + cpu = find_cpu(idx);
> + /* invalid CPU/thread specified */
> + if (!idx || !cpu) {
> + res = -EINVAL;
> + goto out;
> + }
This fails on a packet like vCont;C04:0;c where we do find a cpu but it
happens to have a internal cpu_index of 0.
I'm sending a patch.
--
Alex Bennée
