Re: [PATCH v15 07/10] tb-stats: Adding info [tb-list|tb] commands to HMP (WIP)

[Wu, Fei]

On 6/7/2023 8:24 PM, Fei Wu wrote:
> +void hmp_info_tb(Monitor *mon, const QDict *qdict)
> +{
> +    const int id = qdict_get_int(qdict, "id");
> +    g_autoptr(GString) buf = g_string_new("");
> +
> +    if (!tcg_enabled()) {
> +        monitor_printf(mon, "Only available with accel=tcg\n");
> +        return;
> +    }
> +
> +    TBStatistics *tbs = get_tbstats_by_id(id);
> +    if (tbs == NULL) {
> +        monitor_printf(mon, "TB %d information is not recorded\n", id);
> +        return;
> +    }
> +
> +    monitor_printf(mon, "\n------------------------------\n\n");
> +
> +    int valid_tb_num = dump_tb_info(buf, tbs, id);
> +    monitor_printf(mon, "%s", buf->str);
> +
> +    if (valid_tb_num > 0) {
> +        unsigned num_inst = tbs->code.num_guest_inst / 
> tbs->translations.total;
> +
> +        monitor_printf(mon, "\n----------------n\n");
> +        // FIXME: cannot disas
> +        monitor_disas(mon, mon_get_cpu(mon), tbs->phys_pc, num_inst, true);
> +        monitor_printf(mon, "\n------------------------------\n\n");
> +    }
> +}
> +
So far the following methods are candidates for monitor_disas:

1. still use ram_addr_t for tbs->phys_pc, and extend monitor_disas to
support disassemble ram_addr_t by using qemu_map_ram_ptr(NULL, ram_addr)
to convert it to hva first

2. use gpa for tbs->phys_pc, there is no need to change monitor_disas,
but add another parameter for get_page_addr_code_hostp() to return extra
gpa, probe_access_internal() has already returned CPUTLBEntryFull, so
it's plain to get gpa here.

3. record gpa in another field of tbs, and keep tbs->phys_pc as it is,
this is just a variation of #2.

I'm inclined to use method #2. I think gpa carries more information for
debugging than ram_addr_t, guest can map gpa to the executable file
etc., but it has little knowledge of ram_addr_t.

What do you suggest?

Thanks,
Fei.