Commit Graph

9 Commits

Author SHA1 Message Date
Christian Borntraeger
066f4d82a6 virtio_blk: check for hardsector size from host
Currently virtio_blk assumes a 512 byte hard sector size. This can cause
trouble / performance issues if the backing has a different block size
(like a file on an ext3 file system formatted with 4k block size or a dasd).

Lets add a feature flag that tells the guest to use a different hard sector
size than 512 byte.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-07-25 12:06:05 +10:00
Rusty Russell
674bfc23c5 virtio: clarify that ABI is usable by any implementations
We want others to implement and use virtio, so it makes sense to BSD
license the non-__KERNEL__ parts of the headers to make this crystal
clear.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Mark McLoughlin <markmc@redhat.com>
Acked-by: Ryan Harper <ryanh@us.ibm.com>
Acked-by: Eric Van Hensbergen <ericvh@gmail.com>
Acked-by: Anthony Liguori <aliguori@us.ibm.com>
2008-07-25 12:06:04 +10:00
Christian Borntraeger
7757f09c70 virtio_blk: fix endianess annotations
Since commit 72e61eb40b (virtio: change config
to guest endian) config space is no longer fixed endian.

Lets change the virtio_blk_config variables.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-05-30 15:09:45 +10:00
Christian Borntraeger
3ef5360954 virtio_blk: allow read-only disks
Hello Rusty,

sometimes it is useful to share a disk (e.g. usr). To avoid file system
corruption, the disk should be mounted read-only in that case. This patch
adds a new feature flag, that allows the host to specify, if the disk should
be considered read-only.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-05-30 15:09:44 +10:00
Ryan Harper
48e4043d45 virtio: add virtio disk geometry feature
Rather than faking up some geometry, allow the backend to push the disk
geometry via virtio pci config option.  Keep the old geo code around for
compatibility.

Signed-off-by: Ryan Harper <ryanh@us.ibm.com>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (modified to single struct)
2008-05-02 21:50:51 +10:00
Rusty Russell
cb38fa23c1 virtio: de-structify virtio_block status byte
Ron Minnich points out that a struct containing a char is not always
sizeof(char); simplest to remove the structure to avoid confusion.

Cc: "ron minnich" <rminnich@gmail.com>

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-05-02 21:50:45 +10:00
Rusty Russell
24a5ae5d03 virtio: remove unused id field from struct virtio_blk_outhdr
This field has been unused since an older version of virtio.  Remove
it now before we freeze the ABI.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au.
2008-02-04 23:50:01 +11:00
Rusty Russell
a586d4f601 virtio: simplify config mechanism.
Previously we used a type/len pair within the config space, but this
seems overkill.  We now simply define a structure which represents the
layout in the config space: the config space can now only be extended
at the end.

The main driver-visible changes:
1) We indicate what fields are present with an explicit feature bit.
2) Virtqueues are explicitly numbered, and not in the config space.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-02-04 23:49:57 +11:00
Rusty Russell
e467cde238 Block driver using virtio.
The block driver uses scatter-gather lists with sg[0] being the
request information (struct virtio_blk_outhdr) with the type, sector
and inbuf id.  The next N sg entries are the bio itself, then the last
sg is the status byte.  Whether the N entries are in or out depends on
whether it's a read or a write.

We accept the normal (SCSI) ioctls: they get handed through to the other
side which can then handle it or reply that it's unsupported.  It's
not clear that this actually works in general, since I don't know
if blk_pc_request() requests have an accurate rq_data_dir().

Although we try to reply -ENOTTY on unsupported commands, ioctl(fd,
CDROMEJECT) returns success to userspace.  This needs a separate
patch.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jens Axboe <jens.axboe@oracle.com>
2007-10-23 15:49:54 +10:00