This patch adds trace events that make it possible to observe
virtio-blk.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

in_sg[].iovec and out_sg[].ioved are pointer to (source) host memory and
therefore invalid after migration. When loading the device state we must
create a new mapping on the destination host.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Changing block.h or blockdev.h resulted in recompiling most objects.

Move DriveInfo typedef and BlockInterfaceType enum definitions
to qemu-common.h and rearrange blockdev.h use to decrease churn.
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

Otherwise we can't migrate after we've removed a virtio block device.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Disks without media make no sense.  For SCSI, a Linux guest kernel
complains during boot.  I didn't try other combinations.

scsi-generic doesn't need the additional check, because it already
requires bdrv_is_sg(), which fails without media.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Move the check from virtio_blk_init_pci(), where it protects only
virtio-blk-pci, to virtio_blk_init().  Without that, virtio-blk-s390
initializes without a drive.  I figure that can lead to null pointer
dereferences.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

When available, we'd like to be able to access the DeviceState
when registering a savevm.  For buses with a get_dev_path()
function, this will allow us to create more unique savevm
id strings.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

This patch adds the final missing bits for support of
passing a serial/id string to a virtio-blk guest driver.

The guest-side component already exists in the virtio
driver, and has recently been reworked by Ryan to export
a /sys interface for retrieval of the id from guest userland.
Signed-off-by: Njohn cooper <john.cooper@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

BlockDriverState member removable controls whether virtual media
change (monitor commands change, eject) is allowed.  It is set when
the "type hint" is BDRV_TYPE_CDROM or BDRV_TYPE_FLOPPY.

The type hint is only set by drive_init().  It sets BDRV_TYPE_FLOPPY
for if=floppy.  It sets BDRV_TYPE_CDROM for media=cdrom and if=ide,
scsi, xen, or none.

if=ide and if=scsi work, because the type hint makes it a CD-ROM.
if=xen likewise, I think.

For the same reason, if=none works when it's used by ide-drive or
scsi-disk.  For other guest devices, there are problems:

* fdc: you can't change virtual media

    $ qemu [...] -drive if=none,id=foo,... -global isa-fdc.driveA=foo
    QEMU 0.12.50 monitor - type 'help' for more information
    (qemu) eject foo
    Device 'foo' is not removable

  unless you add media=cdrom, but that makes it readonly.

* virtio: if you add media=cdrom, you can change virtual media.  If
  you eject, the guest gets I/O errors.  If you change, the guest sees
  the drive's contents suddenly change.

* scsi-generic: if you add media=cdrom, you can change virtual media.
  I didn't test what that does to the guest or the physical device,
  but it can't be pretty.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Make the property point to BlockDriverState, cutting out the DriveInfo
middleman.  This prepares the ground for block devices that don't have
a DriveInfo.

Currently all user-defined ones have a DriveInfo, because the only way
to define one is -drive & friends (they go through drive_init()).
DriveInfo is closely tied to -drive, and like -drive, it mixes
information about host and guest part of the block device.  I'm
working towards a new way to define block devices, with clean
host/guest separation, and I need to get DriveInfo out of the way for
that.

Fortunately, the device models are perfectly happy with
BlockDriverState, except for two places: ide_drive_initfn() and
scsi_disk_initfn() need to check the DriveInfo for a serial number set
with legacy -drive serial=...  Use drive_get_by_blockdev() there.

Device model code should now use DriveInfo only when explicitly
dealing with drives defined the old way, i.e. without -device.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Although it is really rare to get in to the while loop, the list
operation in the loop is obviously wrong.
Signed-off-by: NYoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

That's where they belong semantically (block device host part), even
though the actions are actually executed by guest device code.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Pass the MultiReqBuffer structure down all the way to the I/O submission
instead of takin it apart.  Also mark num_writes unsigned as it can't
go negative, and take the check for any pending I/O requests into the
submission function.  Last but not least rename do_multiwrite to
virtio_submit_multiwrite to fit the general naming scheme and make clear
what it does.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

There is a 1:1 relation between VirtIOBlock and BlockDriverState instances,
no need to track it because it won't change.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Anything that moves hundreds of lines out of vl.c can't be all bad.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Clean up virtio-blk.c to be more consistent using BDRV_SECTOR_SIZE
instead of hard coded 512 values.
Signed-off-by: NJes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

Before issuing the barrier to the block driver we need to flush our oustanding
queue of write requests, as the flush is supposed to be issued after them.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The VirtIOBlockRequest structure is about 40 KB in size.  This patch
avoids zeroing every request by only initializing fields that are read.
The other fields are either written to or may not be used at all.

Oprofile shows about 10% of CPU samples in memset called by
virtio_blk_alloc_request().  The workload is
dd if=/dev/vda of=/dev/null iflag=direct bs=8k running concurrently 4
times.  This patch makes memset disappear to the bottom of the profile.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

The bdrv_set_geometry_hint call below is not needed - it's just setting
what was just read.
Signed-off-by: NBruce Rogers <brogers@novell.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

virtio_blk_req_complete frees the request, so we can't access it any more when
calling bdrv_mon_event. Use the pointer that was copied earlier.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

Add a logical block size attribute as various guest side tools only
increase the filesystem sector size based on it, not the advisory
physical block size.

For scsi we already have support for a different logical block size
in place for CDROMs that we can built upon.  Only my recent block
device characteristics VPD page needs some fixups.  Note that we
leave the logial block size for CDROMs hardcoded as the 2k value
is expected for it in general.

For virtio-blk we already have a feature flag claiming to support
a variable logical block size that was added for the s390 kuli
hypervisor.  Interestingly it does not actually change the units
in which the protocol works, which is still fixed at 512 bytes,
but only communicates a different minimum I/O granularity.  So
all we need to do in virtio is to add a trap for unaligned I/O
and round down the device size to the next multiple of the logical
block size.

IDE does not support any other logical block size than 512 bytes.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

The next commit will move the STOP event into do_vm_stop(), to
have the expected event sequence we need to emit the I/O error
event before calling vm_stop().

The expected sequence is:

{ "event": "BLOCK_IO_ERROR" [...] }
{ "event": "STOP" }
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Export all topology information in the block config structure,
guarded by a new VIRTIO_BLK_F_TOPOLOGY feature flag.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Add three new qdev properties to export block topology information to
the guest.  This is needed to get optimal I/O alignment for RAID arrays
or SSDs.

The options are:

 - physical_block_size to specify the physical block size of the device,
   this is going to increase from 512 bytes to 4096 kilobytes for many
   modern storage devices
 - min_io_size to specify the minimal I/O size without performance impact,
   this is typically set to the RAID chunk size for arrays.
 - opt_io_size to specify the optimal sustained I/O size, this is
   typically the RAID stripe width for arrays.

I decided to not auto-probe these values from blkid which might easily
be possible as I don't know how to deal with these issues on migration.

Note that we specificly only set the physical_block_size, and not the
logial one which is the unit all I/O is described in.  The reason for
that is that IDE does not support increasing the logical block size and
at last for now I want to stick to one meachnisms in queue and allow
for easy switching of transports for a given backing image which would
not be possible if scsi and virtio use real 4k sectors, while ide only
uses the physical block exponent.

To make this more common for the different block drivers introduce a
new BlockConf structure holding all common block properties and a
DEFINE_BLOCK_PROPERTIES macro to add them all together, mirroring
what is done for network drivers.  Also switch over all block drivers
to use it, except for the floppy driver which has weird driveA/driveB
properties and probably won't require any advanced block options ever.

Example usage for a virtio device with 4k physical block size and
8k optimal I/O size:

  -drive file=scratch.img,media=disk,cache=none,id=scratch \
  -device virtio-blk-pci,drive=scratch,physical_block_size=4096,opt_io_size=8192

aliguori: updated patch to take into account BLOCK events
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

The addition of the whole ATA IDENTIY page caused the config space to
go above the allowed size in the PCI spec, and thus the feature was
already reverted in the Linux guest driver and disabled by default in
qemu.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Just call bdrv_mon_event() in the right place.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

If an I/O request fails right away instead of getting an error only in the
callback, we still need to consider rerror/werror.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Current code assumes that only write requests are ever going to be restarted.
This is wrong since rerror=stop exists. Instead of directly starting writes,
use the same request processing as used for new requests.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

We need a function that handles a single request. Create one by splitting out
code from virtio_blk_handle_output.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

As pointed out by clang size is only ever written to, but never actually
used.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Add feature bits as properties to virtio. This makes it possible to e.g. define
machine without indirect buffer support, which is required for 0.10
compatibility, or without hardware checksum support, which is required for 0.11
compatibility.  Since default values for optional features are now set by qdev,
get_features callback has been modified: it sets non-optional bits, and clears
bits not supported by host.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Acked-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Either rename variables and functions to refer to write errors (which is what
they actually do) or introduce a parameter to distinguish reads and writes.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

We need to signal not only write errors, but also read errors to the guest
driver. This fixes a regression introduced by 869a5c6d.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Implemented for virtio-blk and for scsi
Signed-off-by: NNaphtali Sprei <nsprei@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Changes:
  * drive_uninit() wants a DriveInfo now.
  * drive_uninit() also calls bdrv_delete(),
    so callers don't need to do that.
  * drive_uninit() calls are moved over to the ->exit()
    callbacks, destroy_bdrvs() is zapped.
  * setting bdrv->private is not needed any more as the
    only user (destroy_bdrvs) is gone.
  * usb-storage needs no drive_uninit, scsi-disk will
    handle that.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Add a new VIRTIO_BLK_F_WCACHE feature to virtio-blk to indicate that we have
a volatile write cache that needs controlled flushing.  Implement a
VIRTIO_BLK_T_FLUSH operation to flush it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

commit bf011293 made virtio-blk-pci not
PCI-compliant, since it makes region 0 (which is an i/o region)
size > 256, and, since PCI 2.1, i/o regions are limited to 256 bytes size.

When the ATA serial number feature is off, which is the default,
make the device spec compliant again, by making region 0 smaller.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reported-by: NVadim Rozenfeld <vrozenfe@redhat.com>
Tested-by: NVadim Rozenfeld <vrozenfe@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

It is quite common for virtio-blk to submit more than one write request in a
row to the qemu block layer. Use bdrv_aio_multiwrite to allow block drivers to
optimize its handling of the requests.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

The bdrv_aio_{read,write} routines can return a NULL pointer when the
I/O submission fails.  Currently we ignore this and will wait forever
for an I/O completion and leading to a hang of the guest.

I can easily reproduce this using the native Linux AIO patch, but it's
also possible using normal pthreads-based AIO.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>