Re: [Qemu-devel] [PATCH v6 07/16] gdbstub: add multiprocess support to (f|s)ThreadInfo and ThreadExtraInfo

["Edgar E. Iglesias" <edgar.iglesias@xilinx.com>]

On Thu, Nov 15, 2018 at 10:41:58AM +0100, Luc Michel wrote:
> Change the thread info related packets handling to support multiprocess
> extension.
> 
> Add the CPUs class name in the extra info to help differentiate
> them in multiprocess mode.
> 
> Signed-off-by: Luc Michel <luc.michel@greensocs.com>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  gdbstub.c | 35 +++++++++++++++++++++++++----------
>  1 file changed, 25 insertions(+), 10 deletions(-)
> 
> diff --git a/gdbstub.c b/gdbstub.c
> index d19b0137e8..292dee8914 100644
> --- a/gdbstub.c
> +++ b/gdbstub.c
> @@ -1260,11 +1260,10 @@ out:
>  static int gdb_handle_packet(GDBState *s, const char *line_buf)
>  {
>      CPUState *cpu;
>      CPUClass *cc;
>      const char *p;
> -    uint32_t thread;
>      uint32_t pid, tid;
>      int ch, reg_size, type, res;
>      uint8_t mem_buf[MAX_PACKET_LENGTH];
>      char buf[sizeof(mem_buf) + 1 /* trailing NUL */];
>      char thread_id[16];
> @@ -1556,30 +1555,46 @@ static int gdb_handle_packet(GDBState *s, const char *line_buf)
>              snprintf(buf, sizeof(buf), "QC%s",
>                       gdb_fmt_thread_id(s, cpu, thread_id, sizeof(thread_id)));
>              put_packet(s, buf);
>              break;
>          } else if (strcmp(p,"fThreadInfo") == 0) {
> -            s->query_cpu = first_cpu;
> +            s->query_cpu = gdb_first_cpu(s);
>              goto report_cpuinfo;
>          } else if (strcmp(p,"sThreadInfo") == 0) {
>          report_cpuinfo:
>              if (s->query_cpu) {
> -                snprintf(buf, sizeof(buf), "m%x", cpu_gdb_index(s->query_cpu));
> +                snprintf(buf, sizeof(buf), "m%s",
> +                         gdb_fmt_thread_id(s, s->query_cpu,
> +                                       thread_id, sizeof(thread_id)));
>                  put_packet(s, buf);
> -                s->query_cpu = CPU_NEXT(s->query_cpu);
> +                s->query_cpu = gdb_next_cpu(s, s->query_cpu);
>              } else
>                  put_packet(s, "l");
>              break;
>          } else if (strncmp(p,"ThreadExtraInfo,", 16) == 0) {
> -            thread = strtoull(p+16, (char **)&p, 16);
> -            cpu = find_cpu(thread);
> +            if (read_thread_id(p + 16, &p, &pid, &tid) == GDB_READ_THREAD_ERR) {
> +                put_packet(s, "E22");
> +                break;
> +            }
> +            cpu = gdb_get_cpu(s, pid, tid);
>              if (cpu != NULL) {
>                  cpu_synchronize_state(cpu);
> -                /* memtohex() doubles the required space */
> -                len = snprintf((char *)mem_buf, sizeof(buf) / 2,
> -                               "CPU#%d [%s]", cpu->cpu_index,
> -                               cpu->halted ? "halted " : "running");
> +
> +                if (s->multiprocess && (s->process_num > 1)) {
> +                    /* Print the CPU model in multiprocess mode */
> +                    ObjectClass *oc = object_get_class(OBJECT(cpu));
> +                    const char *cpu_model = object_class_get_name(oc);
> +                    len = snprintf((char *)mem_buf, sizeof(buf) / 2,
> +                                   "CPU#%d %s [%s]", cpu->cpu_index,
> +                                   cpu_model,
> +                                   cpu->halted ? "halted " : "running");



I wonder if we could also print a friendly name here deducted from QOM?
In some of our use-cases we have an array of MicroBlazes that all live
in different HW subsystems and are named differently (e.g CSU, PMU, PMC,
PSM etc).

Instead of just seeing a list of MicroBlaze cores it may be more useful
to see the actual core name of some sort, e.g:

Instead of:
CPU#0 MicroBlaze [running]
CPU#1 MicroBlaze [running]
CPU#2 MicroBlaze [running]
CPU#3 MicroBlaze [running]

Perhaps something like:
CPU#0 MicroBlaze PMU [running]
CPU#1 MicroBlaze PMC-PPU0 [running]
CPU#2 MicroBlaze PMC-PPU1 [running]
CPU#3 MicroBlaze PSM [running]

Any thoughts on that?

Thanks,
Edgar

> +                } else {
> +                    /* memtohex() doubles the required space */
> +                    len = snprintf((char *)mem_buf, sizeof(buf) / 2,
> +                                   "CPU#%d [%s]", cpu->cpu_index,
> +                                   cpu->halted ? "halted " : "running");
> +                }
>                  trace_gdbstub_op_extra_info((char *)mem_buf);
>                  memtohex(buf, mem_buf, len);
>                  put_packet(s, buf);
>              }
>              break;
> -- 
> 2.19.1
>