Re: [Qemu-devel] [PATCH 1/3] s390: Fix empty kernel command line

[Christian Borntraeger <borntraeger@de.ibm.com>]

On 11/12/12 12:19, Alexander Graf wrote:
> 
> On 11.12.2012, at 12:15, Christian Borntraeger wrote:
> 
>> On 11/12/12 11:34, Alexander Graf wrote:
>>>
>>> On 07.12.2012, at 14:55, Jens Freimann wrote:
>>>
>>>> From: Christian Borntraeger <borntraeger@de.ibm.com>
>>>>
>>>> Since commit 967c0da73a7b0da186baba6632301d83644a570c
>>>>   vl.c: Avoid segfault when started with no arguments
>>>>
>>>> the user can specify a kernel without a command line. Lets not
>>>> overwrite the default command line with \0 in that case.
>>>>
>>>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>>>> Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
>>>> ---
>>>> hw/s390-virtio.c |    2 +-
>>>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
>>>> index ca1bb09..d77871a 100644
>>>> --- a/hw/s390-virtio.c
>>>> +++ b/hw/s390-virtio.c
>>>> @@ -290,7 +290,7 @@ static void s390_init(QEMUMachineInitArgs *args)
>>>>        stq_p(rom_ptr(INITRD_PARM_SIZE), initrd_size);
>>>>    }
>>>>
>>>> -    if (rom_ptr(KERN_PARM_AREA)) {
>>>> +    if (rom_ptr(KERN_PARM_AREA) && strlen(kernel_cmdline)) {
>>>
>>> why strlen()? If no -append option was passed, kernel_cmdline should be NULL. If -append "" was passed, the user wants to command line to be overwritten with "\0".
>>
>> Nope. kernel_cmdline is always a valid pointer.
>>
>> vl.c:
>>
>> [..]
>>    if (!kernel_cmdline) {
>>        kernel_cmdline = "";
>>    }
> 
> Then that's on purpose. Either we change the default for everyone or not at all. But checking for "" only in the s390 machine sounds off.

Ok, makes sense.