Re: [PATCH v4 21/29] gdbstub: expose api to find registers

[Akihiko Odaki <akihiko.odaki@daynix.com>]

On 2024/02/27 23:43, Alex Bennée wrote:
> Expose an internal API to QEMU to return all the registers for a vCPU.
> The list containing the details required to called gdb_read_register().
> 
> Based-on: <20231025093128.33116-15-akihiko.odaki@daynix.com>
> Cc: Akihiko Odaki <akihiko.odaki@daynix.com>
> Message-Id: <20240103173349.398526-38-alex.bennee@linaro.org>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>

> 
> ---
> v3
>    - rm unused api functions left over
> ---
>   include/exec/gdbstub.h | 28 ++++++++++++++++++++++++++++
>   gdbstub/gdbstub.c      | 27 ++++++++++++++++++++++++++-
>   2 files changed, 54 insertions(+), 1 deletion(-)
> 
> diff --git a/include/exec/gdbstub.h b/include/exec/gdbstub.h
> index da9ddfe54c5..eb14b91139b 100644
> --- a/include/exec/gdbstub.h
> +++ b/include/exec/gdbstub.h
> @@ -111,6 +111,34 @@ void gdb_feature_builder_end(const GDBFeatureBuilder *builder);
>    */
>   const GDBFeature *gdb_find_static_feature(const char *xmlname);
>   
> +/**
> + * gdb_read_register() - Read a register associated with a CPU.
> + * @cpu: The CPU associated with the register.
> + * @buf: The buffer that the read register will be appended to.
> + * @reg: The register's number returned by gdb_find_feature_register().
> + *
> + * Return: The number of read bytes.
> + */
> +int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg);
> +
> +/**
> + * typedef GDBRegDesc - a register description from gdbstub
> + */
> +typedef struct {
> +    int gdb_reg;
> +    const char *name;
> +    const char *feature_name;
> +} GDBRegDesc;
> +
> +/**
> + * gdb_get_register_list() - Return list of all registers for CPU
> + * @cpu: The CPU being searched
> + *
> + * Returns a GArray of GDBRegDesc, caller frees array but not the
> + * const strings.
> + */
> +GArray *gdb_get_register_list(CPUState *cpu);
> +
>   void gdb_set_stop_cpu(CPUState *cpu);
>   
>   /* in gdbstub-xml.c, generated by scripts/feature_to_c.py */
> diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
> index a55b5e6581a..2909bc8c69f 100644
> --- a/gdbstub/gdbstub.c
> +++ b/gdbstub/gdbstub.c
> @@ -490,7 +490,32 @@ const GDBFeature *gdb_find_static_feature(const char *xmlname)
>       g_assert_not_reached();
>   }
>   
> -static int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg)
> +GArray *gdb_get_register_list(CPUState *cpu)
> +{
> +    GArray *results = g_array_new(true, true, sizeof(GDBRegDesc));
> +
> +    /* registers are only available once the CPU is initialised */
> +    if (!cpu->gdb_regs) {
> +        return results;
> +    }
> +
> +    for (int f = 0; f < cpu->gdb_regs->len; f++) {
> +        GDBRegisterState *r = &g_array_index(cpu->gdb_regs, GDBRegisterState, f);
> +        for (int i = 0; i < r->feature->num_regs; i++) {
> +            const char *name = r->feature->regs[i];
> +            GDBRegDesc desc = {
> +                r->base_reg + i,
> +                name,
> +                r->feature->name
> +            };
> +            g_array_append_val(results, desc);
> +        }
> +    }
> +
> +    return results;
> +}
> +
> +int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg)
>   {
>       CPUClass *cc = CPU_GET_CLASS(cpu);
>       GDBRegisterState *r;