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

["Daniel P. Berrange" <berrange@redhat.com>]

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

Regards,
Daniel
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