Re: [Qemu-devel] Hang when using 9p mounts after last Seabios update

[Chris Krumme <Chris.Krumme@windriver.com>]

On 10/11/2011 03:30 AM, Daniel P. Berrange wrote:
> On Sat, Oct 01, 2011 at 12:50:43PM -0400, Kevin O'Connor wrote:
>> On Thu, Sep 22, 2011 at 12:45:11PM +0100, Daniel P. Berrange wrote:
>>> On 0.14, 0.15 releaes, this all works just fine. On current GIT master,
>>> the guest OS will hang during boot.
>> [...]
>>> To reproduce this you will need my custom initrd for mounting 9p filesystems
>>> as the root FS. You can get that here:
>>>
>>>    http://berrange.com/~dan/qemu-serial-hang-demo.tar.gz
>> Thanks for the detailed report.
>>
>> I've confirmed the issue and tracked it down.  The current SeaBIOS
>> code gets confused during alignment checking if there are no prefmem
>> regions found.
>>
>> The patch below should fix the issue.
> Thanks, I have tested Seabios 1.6.3 which includes that patch, and
> can confirm that it does fix the hang I saw.
>
> Anthony/Gerd: we can get QEMU master updated to Seabios 1.6.3 before
> the 1.0 release ?
>
>> Author: Kevin O'Connor<kevin@koconnor.net>
>> Date:   Sat Oct 1 12:35:32 2011 -0400
>>
>>      Fix alignment bug in pci_bios_init_root_regions().
>>
>>      If there are no memory allocations for a given type then the "max" bar
>>      size is zero.  However, ALIGN_DOWN does not handle an alignment of
>>      zero properly.  Catch and handle the zero case.
>>
>>      Signed-off-by: Kevin O'Connor<kevin@koconnor.net>
>>
>> diff --git a/src/pciinit.c b/src/pciinit.c
>> index a857da0..0d8758e 100644
>> --- a/src/pciinit.c
>> +++ b/src/pciinit.c
>> @@ -536,7 +536,7 @@ static void pci_bios_init_bus_bases(struct pci_bus *bus)
>>       }
>>   }
>>
>> -#define ROOT_BASE(top, sum, align) ALIGN_DOWN((top)-(sum),(align))
>> +#define ROOT_BASE(top, sum, max) ALIGN_DOWN((top)-(sum),(max) ?: 1)

Hello,

This is adding a GNUism, can this be:  (max)?(max):1

Thanks

Chris

>>
>>   static int pci_bios_init_root_regions(u32 start, u32 end)
>>   {
> Regards,
> Daniel