Re: [Qemu-devel] [PATCH v2 0/6] Geometry and blocksize support for backing devices

[Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>]

On 11/28/2014 01:35 PM, Stefan Hajnoczi wrote:
> On Wed, Nov 26, 2014 at 01:16:48PM +0300, Ekaterina Tumanova wrote:
>> On 11/25/2014 04:01 PM, Stefan Hajnoczi wrote:
>>> On Wed, Nov 19, 2014 at 11:17:50AM +0100, Ekaterina Tumanova wrote:
>>> 3. Why does s390 need to customize hd_geometry_guess()?
>>>
>> Since hd_geometry_guess contains semantics of x86-specific LBA translation,
>> we have to modify it not to get in the way of z
>> architecture
>
> If the behavior is x86-specific, it should be made x86-specific.  z,
> ppc, sparc, arm, etc should share the non-x86-specific code path.  It's
> weird to single out z here, this seems like the wrong way around.
>
> Is the x86-specific behavior a problem in practice?  No one seemed to
> mind for the other targets.
>

on s390 arch this adds support for FCP attached SCSI disks that do not
yet have a partition table. Without this patch, fdisk -l on the host
would return different results then fdisk -l in the guest.

If you guys don't like the way patch goes, I can exclude it from patch
series and we can discuss it later.

But I thought that since it's related to the hard drive geometry,
and since we change hd_geometry_guess in this patchset anyway, why not
get rid of this problem as well.

Kate.