Re: [Qemu-devel] [PATCH] hw/arm/virt: fix cmdline parsing bug with CPU options and smp > 1

[Ard Biesheuvel]

On 4 March 2015 at 08:10, Ard Biesheuvel <address@hidden> wrote:
> On 3 March 2015 at 19:25, Greg Bellows <address@hidden> wrote:
>>
>>
>> On Tue, Mar 3, 2015 at 11:06 AM, Ard Biesheuvel <address@hidden>
>> wrote:
>>>
>>> The recently introduced feature that allows 32 bit guests to be
>>> executed under KVM on a 64-bit host incorrectly handles the case
>>> where more than 1 cpu is specified using '-smp N'
>>>
>>> For instance, this invocation of qemu
>>>
>>>   qemu-system-aarch64 -M virt -cpu cortex-a57,aarch64=off -smp 2
>>>
>
> This is incorrect: it is the command line I used for reproducing the
> issue while working on the bug, after removing the KVM check.
> So this should read
>
>>>   qemu-system-aarch64 -M virt -enable-kvm -cpu host,aarch64=off -smp 2
>
>
>>> produces the following error
>>>
>>>   qemu-system-aarch64: Expected key=value format, found aarch64
>>>
>>> which is caused by the destructive parsing performed by
>>> cpu_common_parse_features(), resulting in subsequent attempts
>>> to parse the CPU option string (for each additional CPU) to fail.
>>>
>>> So duplicate the string before parsing it, and free it directly
>>> afterwards.
>>>
>>> Signed-off-by: Ard Biesheuvel <address@hidden>
>>> ---
>>>  hw/arm/virt.c | 4 +++-
>>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>>> index 69f51ac0da58..f8a6c46323dc 100644
>>> --- a/hw/arm/virt.c
>>> +++ b/hw/arm/virt.c
>>> @@ -758,6 +758,7 @@ static void machvirt_init(MachineState *machine)
>>>          CPUClass *cc = CPU_CLASS(oc);
>>>          Object *cpuobj;
>>>          Error *err = NULL;
>>> +        char *cpuopts = g_strdup(cpustr[1]);
>>>
>>>          if (!oc) {
>>>              fprintf(stderr, "Unable to find CPU definition\n");
>>> @@ -766,7 +767,8 @@ static void machvirt_init(MachineState *machine)
>>>          cpuobj = object_new(object_class_get_name(oc));
>>>
>>>          /* Handle any CPU options specified by the user */
>>> -        cc->parse_features(CPU(cpuobj), cpustr[1], &err);
>>> +        cc->parse_features(CPU(cpuobj), cpuopts, &err);
>>> +        g_free(cpuopts);
>>>          if (err) {
>>>              error_report("%s", error_get_pretty(err));
>>>              exit(1);
>>> --
>>> 1.8.3.2
>>>
>> Saw your patch after I sent mine out, roughly same fix...
>>
>> Reviewed-by: Greg Bellows <address@hidden>
>>
>
> Thanks.
>
> Let's leave it up to Peter which version he is most happy with
>

Ping?