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From: Alex =?utf-8?Q?Benn=C3=A9e?= <alex.bennee@linaro.org>
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Date: Wed, 31 May 2017 17:27:04 +0100
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Subject: Re: [Qemu-devel] [PATCH v1 2/2] gdbstub: don't fail on vCont; C04:0;
 c packets
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To: Greg Kurz <groug@kaod.org>
Cc: pbonzini@redhat.com, doug16k@gmail.com, imbrenda@linux.vnet.ibm.com, qemu-devel@nongnu.org


Greg Kurz <groug@kaod.org> writes:

> On Wed, 31 May 2017 16:09:33 +0100
> Alex Bennée <alex.bennee@linaro.org> 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;
>             }

Yeah that will make it cleaner, I'll apply to v2.

>
> Anyway, the fix looks ok.
>
> Reviewed-by: Greg Kurz <groug@kaod.org>
>
>> 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 <alex.bennee@linaro.org>
>> ---
>>  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;
>>              }


--
Alex Bennée