[Qemu-devel] [PATCH 0/1] Fixup for DASD geometry detection

[Qemu-devel] [PATCH 0/1] Fixup for DASD geometry detection

[Christian Borntraeger]

Kevin,

here is a fixup for the geometry detection. We tried to be overly
clever and calculate the cyclinder size for devices > 64k cyls. Now
this is wrong for the cyls parameter as the interface only has
16bit. Large DASD devices have a special token (0xfffe) that 
indicate to the DASD related code, that you have to calculate
the cyls size yourself.

Without this patch QEMU cannot pass through bigger DASD disks
and complains "cyls must be between 1 and 65535"


Christian Borntraeger (1):
  block/raw-posix: avoid bogus fixup for cylinders on DASD disks

 block/raw-posix.c | 7 -------
 1 file changed, 7 deletions(-)

-- 
2.3.0

[Qemu-devel] [PATCH 1/1] block/raw-posix: avoid bogus fixup for cylinders on DASD disks

[Christian Borntraeger]

large volume DASD that have > 64k cylinders do claim to have
0xFFFE cylinders as special value in the old 16 bit field. We
want to pass this "token" along to the guest, instead of
calculating the real number. Otherwise qemu might fail with
"cyls must be between 1 and 65535"

Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 block/raw-posix.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index d9162fd..2fff184 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -783,7 +783,6 @@ static int hdev_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
 {
     BDRVRawState *s = bs->opaque;
     struct hd_geometry ioctl_geo = {0};
-    uint32_t blksize;
 
     /* If DASD, get its geometry */
     if (check_for_dasd(s->fd) < 0) {
@@ -803,12 +802,6 @@ static int hdev_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
     }
     geo->heads = ioctl_geo.heads;
     geo->sectors = ioctl_geo.sectors;
-    if (!probe_physical_blocksize(s->fd, &blksize)) {
-        /* overwrite cyls: HDIO_GETGEO result is incorrect for big drives */
-        geo->cylinders = bdrv_nb_sectors(bs) / (blksize / BDRV_SECTOR_SIZE)
-                                             / (geo->heads * geo->sectors);
-        return 0;
-    }
     geo->cylinders = ioctl_geo.cylinders;
 
     return 0;
-- 
2.3.0

Re: [Qemu-devel] [PATCH 1/1] block/raw-posix: avoid bogus fixup for cylinders on DASD disks

[Markus Armbruster]

Christian Borntraeger <borntraeger@de.ibm.com> writes:

> large volume DASD that have > 64k cylinders do claim to have
> 0xFFFE cylinders as special value in the old 16 bit field. We
> want to pass this "token" along to the guest, instead of
> calculating the real number. Otherwise qemu might fail with
> "cyls must be between 1 and 65535"
>
> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

Reviewed-by: Markus Armbruster <armbru@redhat.com>

Re: [Qemu-devel] [PATCH 1/1] block/raw-posix: avoid bogus fixup for cylinders on DASD disks

[Cornelia Huck]

On Mon, 14 Dec 2015 16:41:19 +0100
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> large volume DASD that have > 64k cylinders do claim to have
> 0xFFFE cylinders as special value in the old 16 bit field. We
> want to pass this "token" along to the guest, instead of
> calculating the real number. Otherwise qemu might fail with
> "cyls must be between 1 and 65535"
> 
> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  block/raw-posix.c | 7 -------
>  1 file changed, 7 deletions(-)

Maybe add cc:stable?

Re: [Qemu-devel] [PATCH 1/1] block/raw-posix: avoid bogus fixup for cylinders on DASD disks

[Christian Borntraeger]

On 12/14/2015 06:49 PM, Cornelia Huck wrote:
> On Mon, 14 Dec 2015 16:41:19 +0100
> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
> 
>> large volume DASD that have > 64k cylinders do claim to have
>> 0xFFFE cylinders as special value in the old 16 bit field. We
>> want to pass this "token" along to the guest, instead of
>> calculating the real number. Otherwise qemu might fail with
>> "cyls must be between 1 and 65535"
>>
>> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>>  block/raw-posix.c | 7 -------
>>  1 file changed, 7 deletions(-)
> 
> Maybe add cc:stable?

Yes.

Kevin, ping. I assume this goes via your tree?

Re: [Qemu-devel] [PATCH 0/1] Fixup for DASD geometry detection

[Kevin Wolf]

Am 14.12.2015 um 16:41 hat Christian Borntraeger geschrieben:
> Kevin,
> 
> here is a fixup for the geometry detection. We tried to be overly
> clever and calculate the cyclinder size for devices > 64k cyls. Now
> this is wrong for the cyls parameter as the interface only has
> 16bit. Large DASD devices have a special token (0xfffe) that 
> indicate to the DASD related code, that you have to calculate
> the cyls size yourself.
> 
> Without this patch QEMU cannot pass through bigger DASD disks
> and complains "cyls must be between 1 and 65535"

Thanks, applied to the block branch.

Kevin