Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0; c packets

[Greg Kurz]

On Wed, 31 May 2017 16:09:33 +0100
Alex Bennée <address@hidden> wrote:

> The thread-id of 0 means any CPU but we then ignore the fact we find
> the first_cpu in this case who can have an index of 0. Instead of

The index can never be 0 in system mode actually, but you're right that this
check doesn't make sense.

The code still looks a bit convoluted IMHO. What about something like the
following ?

            /* 0 means any thread, so we pick the first valid CPU */
            cpu = tmp ? find_cpu(tmp) : first_cpu;

            /* invalid CPU/thread specified */
            if (!cpu) {
                res = -EINVAL;
                goto out;
            }

Anyway, the fix looks ok.

Reviewed-by: Greg Kurz <address@hidden>

> bailing out just test if we have managed to match up thread-id to a
> CPU.
> 
> Otherwise you get:
>   gdb_handle_packet: command='vCont;C04:0;c'
>   put_packet: reply='E22'
> 
> Signed-off-by: Alex Bennée <address@hidden>
> ---
>  gdbstub.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/gdbstub.c b/gdbstub.c
> index a249846954..29c9ed3002 100644
> --- a/gdbstub.c
> +++ b/gdbstub.c
> @@ -934,8 +934,8 @@ static int gdb_handle_vcont(GDBState *s, const char *p)
>               * CPU first, and only then we can use its index.
>               */
>              cpu = find_cpu(idx);
> -            /* invalid CPU/thread specified */
> -            if (!idx || !cpu) {
> +            /* invalid thread specified, cpu not found. */
> +            if (!cpu) {
>                  res = -EINVAL;
>                  goto out;
>              }

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