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2015-02-16dataplane: endianness-aware accessesCornelia Huck1-1/+3
The vring.c code currently assumes that guest and host endianness match, which is not true for a number of cases: - emulating targets with a different endianness than the host - bi-endian targets, where the correct endianness depends on the virtio device - upcoming support for the virtio-1 standard mandates little-endian accesses even for big-endian targets and hosts Make sure to use accessors that depend on the virtio device. Note that dataplane now needs to be built per-target. Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Fam Zheng <famz@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Tested-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1422289602-17874-2-git-send-email-cornelia.huck@de.ibm.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-02-06virtio-blk: introduce multireadPeter Lieven1-4/+4
this patch finally introduces multiread support to virtio-blk. While multiwrite support was there for a long time, read support was missing. The complete merge logic is moved into virtio-blk.c which has been the only user of request merging ever since. This is required to be able to merge chunks of requests and immediately invoke callbacks for those requests. Secondly, this is required to switch to direct invocation of coroutines which is planned at a later stage. The following benchmarks show the performance of running fio with 4 worker threads on a local ram disk. The numbers show the average of 10 test runs after 1 run as warmup phase. | 4k | 64k | 4k MB/s | rd seq | rd rand | rd seq | rd rand | wr seq | wr rand --------------+--------+---------+--------+---------+--------+-------- master | 1221 | 1187 | 4178 | 4114 | 1745 | 1213 multiread | 1829 | 1189 | 4639 | 4110 | 1894 | 1216 Signed-off-by: Peter Lieven <pl@kamp.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-01-13block: Split BLOCK_OP_TYPE_COMMIT to BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET}Fam Zheng1-1/+2
Like BLOCK_OP_TYPE_BACKUP_SOURCE and BLOCK_OP_TYPE_BACKUP_TARGET, block-commit involves two asymmetric devices. This change is not user-visible (yet), because commit only works with device names. But once we enable backing reference in blockdev-add, or specifying node-name in block-commit command, we don't want the user to start two commit jobs on the same backing chain, which will corrupt things because of the final bdrv_swap. Before we have per category blockers, splitting this type is still better. [Resolved virtio-blk dataplane conflict by replacing BLOCK_OP_TYPE_COMMIT with both BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET}. They are safe since the block job runs in the same AioContext as the dataplane IOThread. --Stefan] Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-12-10blockdev: acquire AioContext in QMP 'transaction' actionsStefan Hajnoczi1-0/+2
The transaction QMP command performs operations atomically on a group of drives. This command needs to acquire AioContext in order to work safely when virtio-blk dataplane IOThreads are accessing drives. The transactional nature of the command means that actions are split into prepare, commit, abort, and clean functions. Acquire the AioContext in prepare and don't release it until one of the other functions is called. This prevents the IOThread from running the AioContext before the transaction has completed. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 1416566940-4430-4-git-send-email-stefanha@redhat.com Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10blockdev: acquire AioContext in change-backing-fileStefan Hajnoczi1-0/+1
Add dataplane support to the change-backing-file QMP commands. By acquiring the AioContext we avoid race conditions with the dataplane thread which may also be accessing the BlockDriverState. Note that this command operates on both bs and a node in its chain (image_bs). The bdrv_chain_contains(bs, image_bs) check guarantees that bs and image_bs are in the same AioContext. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10blockdev: acquire AioContext in eject, change, and block_passwdStefan Hajnoczi1-0/+1
By acquiring the AioContext we avoid race conditions with the dataplane thread which may also be accessing the BlockDriverState. Fix up eject, change, and block_passwd in a single patch because qmp_eject() and qmp_change_blockdev() both call eject_device(). Also fix block_passwd while we're tackling a command that takes a block encryption password. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-12-10blockdev: acquire AioContext in blockdev-snapshot-delete-internal-syncStefan Hajnoczi1-0/+2
Add dataplane support to the blockdev-snapshot-delete-internal-sync QMP command. By acquiring the AioContext we avoid race conditions with the dataplane thread which may also be accessing the BlockDriverState. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-11-03block: declare blockjobs and dataplane friends!Stefan Hajnoczi1-0/+5
Now that blockjobs use AioContext they are safe for use with dataplane. Unblock them! Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 1413889440-32577-12-git-send-email-stefanha@redhat.com
2014-10-20hw: Convert from BlockDriverState to BlockBackend, mostlyMarkus Armbruster1-12/+12
Device models should access their block backends only through the block-backend.h API. Convert them, and drop direct includes of inappropriate headers. Just four uses of BlockDriverState are left: * The Xen paravirtual block device backend (xen_disk.c) opens images itself when set up via xenbus, bypassing blockdev.c. I figure it should go through qmp_blockdev_add() instead. * Device model "usb-storage" prompts for keys. No other device model does, and this one probably shouldn't do it, either. * ide_issue_trim_cb() uses bdrv_aio_discard() instead of blk_aio_discard() because it fishes its backend out of a BlockAIOCB, which has only the BlockDriverState. * PC87312State has an unused BlockDriverState[] member. The next two commits take care of the latter two. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20virtio-blk: Rename VirtIOBlkConf variables to confMarkus Armbruster2-17/+18
This is consistent with how VirtIOFOOConf variables are named elsewhere, and makes blk available for BlockBackend variables. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-11dataplane: fix virtio_blk_data_plane_create() op blocker error pathStefan Hajnoczi1-2/+2
Commit 3718d8ab65f68de2acccbe6a315907805f54e3cc ("block: Replace in_use with operation blocker") broke the error path because it consumed local_err instead of propagating it. The caller has no way to know that the function failed. This caused virtio-blk to start "successfully" even though there was a fatal dataplane error. Steps to reproduce: $ qemu-system-x86_64 -enable-kvm -object iothread,id=iothread0 \ -drive if=none,id=drive0,file=a.img \ (qemu) drive_mirror drive0 /tmp/foo.img (qemu) device_add virtio-blk-pci,iothread=iothread0,drive=drive0 Expected result: Since the mirror block job is using drive0 it is not possible to start virtio-blk data-plane. device_add fails and the PCI adapter is not added. Actual result: device_add completes and the PCI adapter is added. Cc: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-29virtio-blk: allow drive_del with dataplaneStefan Hajnoczi1-0/+1
Now that drive_del acquires the AioContext we can safely allow deleting the drive. As with non-dataplane mode, all I/Os submitted by the guest after drive_del will return EIO. This patch makes hot unplug work with virtio-blk dataplane. Previously drive_del reported an error because the device was busy. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-20virtio-blk: allow block_resize with dataplaneStefan Hajnoczi1-0/+1
Now that block_resize acquires the AioContext we can safely allow resizing the disk. Reported-by: Andrey Korolyov <andrey@xdel.ru> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-08-15dataplane: stop trying on notifier errorCornelia Huck1-1/+10
If we fail to set up guest or host notifiers, there's no use trying again every time the guest kicks, so disable dataplane in that case. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15dataplane: fail notifier setting gracefullyCornelia Huck1-4/+11
The dataplane code is currently doing a hard exit if it fails to set up either guest or host notifiers. In practice, this may mean that a guest suddenly dies after a dataplane device failed to come up (e.g., when a file descriptor limit is hit for tne nth device). Let's just try to unwind the setup instead and return. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15dataplane: print why starting failedCornelia Huck1-5/+8
Setting up guest or host notifiers may fail, but the user will have no idea why: Let's print the error returned by the callback. Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-15virtio-blk: dataplane: notify guest as a batchMing Lei1-1/+19
Now requests are submitted as a batch, so it is natural to notify guest as a batch too. This may suppress interrupt notification to VM a lot: - in my test, decreased by ~13K/sec Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-15virtio-blk: data-plane: fix save/set .complete_request in startMing Lei1-3/+4
The callback has to be saved and reset in virtio_blk_data_plane_start(), otherwise dataplane's requests will be completed in qemu aio context. Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-14virtio-blk: embed VirtQueueElement in VirtIOBlockReqStefan Hajnoczi1-15/+14
The memory allocation between hw/block/virtio-blk.c, hw/block/dataplane/virtio-blk.c, and hw/virtio/dataplane/vring.c is messy. Structs are allocated in different files than they are freed in. This is risky and makes memory leaks easier. Embed VirtQueueElement in VirtIOBlockReq to reduce the amount of memory allocation we need to juggle. This also makes vring.c and virtio.c slightly more similar. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-07-14virtio-blk: avoid dataplane VirtIOBlockReq early freeStefan Hajnoczi1-1/+0
VirtIOBlockReq is freed later by virtio_blk_free_request() in hw/block/virtio-blk.c. Remove this extraneous g_slice_free(). This patch fixes the following segfault: 0x00005555556373af in virtio_blk_rw_complete (opaque=0x5555565ff5e0, ret=0) at hw/block/virtio-blk.c:99 99 bdrv_acct_done(req->dev->bs, &req->acct); (gdb) print req $1 = (VirtIOBlockReq *) 0x5555565ff5e0 (gdb) print req->dev $2 = (VirtIOBlock *) 0x0 (gdb) bt #0 0x00005555556373af in virtio_blk_rw_complete (opaque=0x5555565ff5e0, ret=0) at hw/block/virtio-blk.c:99 #1 0x0000555555840ebe in bdrv_co_em_bh (opaque=0x5555566152d0) at block.c:4675 #2 0x000055555583de77 in aio_bh_poll (ctx=ctx@entry=0x5555563a8150) at async.c:81 #3 0x000055555584b7a7 in aio_poll (ctx=0x5555563a8150, blocking=blocking@entry=true) at aio-posix.c:188 #4 0x00005555556e520e in iothread_run (opaque=0x5555563a7fd8) at iothread.c:41 #5 0x00007ffff42ba124 in start_thread () from /usr/lib/libpthread.so.0 #6 0x00007ffff16d14bd in clone () from /usr/lib/libc.so.6 Reported-by: Max Reitz <mreitz@redhat.com> Cc: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-07-07dataplane: submit I/O as a batchMing Lei1-0/+2
Before commit 580b6b2aa2(dataplane: use the QEMU block layer for I/O), dataplane for virtio-blk submits block I/O as a batch. This commit 580b6b2aa2 replaces the custom linux AIO implementation(including submit I/O as a batch) with QEMU block layer, but this commit causes ~40% throughput regression on virtio-blk performance, and removing submitting I/O as a batch is one of the causes. This patch applies the newly introduced bdrv_io_plug() and bdrv_io_unplug() interfaces to support submitting I/O at batch for Qemu block layer, and in my test, the change can improve throughput by ~30% with 'aio=native'. Following my fio test script: [global] direct=1 size=4G bsrange=4k-4k timeout=40 numjobs=4 ioengine=libaio iodepth=64 filename=/dev/vdc group_reporting=1 [f] rw=randread Result on one of my small machine(host: x86_64, 2cores, 4thread, guest: 4cores): - qemu master: 65K IOPS - qemu master with these patches: 92K IOPS - 2.0.0 release(dataplane using custom linux aio): 104K IOPS Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01virtio-blk: remove need for explicit x-data-plane=on optionStefan Hajnoczi1-1/+1
The x-data-plane=on|off option is no longer useful because the iothread=<iothread> option conveys the same information plus which IOThread to use. Do not delete x-data-plane=on|off yet as a convenience to people using this legacy experimental option. We will drop it in QEMU 2.2. Instead, turn on data-plane when either x-data-plane=on or iothread=<iothread> are used. The following command-line uses data-plane: qemu -device virtio-blk-pci,iothread=foo,drive=drive0 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-07-01dataplane: bail out on unsupported transportCornelia Huck1-0/+10
If the virtio transport does not support notifiers (like s390-virtio), we can't use dataplane. Bail out early and let the user know what is wrong. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-27virtio-blk: Rename complete_request_early to complete_request_vringFam Zheng1-2/+2
The old name is misleading in its new usage, so rename it. Signed-off-by: Fam Zheng <famz@redhat.com> Tested-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27virtio-blk: Unify {non-,}dataplane's request handlingsFam Zheng1-164/+19
This drops request handling code from dataplane, and uses code from hw/block/virtio-blk.c. It starts to use multiwrite as non-dataplane does. Dataplane sets VirtIOBlock.complete_request to vring version, and calls into non-dataplane's process handling. In complete_request_early, qiov.size is added to vring push length, because it's also called in rw completion now. Signed-off-by: Fam Zheng <famz@redhat.com> Tested-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27virtio-blk: Fill in VirtIOBlockReq.out in dataplane codeFam Zheng1-58/+44
VirtIOBlockReq is allocated in process_request, and freed in command functions. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27virtio-blk: Use VirtIOBlockReq.in to drop VirtIOBlockReq.inhdrFam Zheng1-32/+22
In current virtio spec, inhdr is a single byte, and is unlikely to change for both functionality and compatibility considerations. Non-dataplane uses .in, and we are on the way to converge them. So let's unify it to get cleaner code. Remove .inhdr and use .in. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27virtio-blk: Replace VirtIOBlockRequest with VirtIOBlockReqFam Zheng1-19/+15
Field "inhdr" is added temporarily for a more mechanical change, and will be dropped in the next commit. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27virtio-blk: Drop VirtIOBlockRequest.readFam Zheng1-2/+0
Since it's set but not used. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-27virtio-blk: Drop bounce buffer from dataplane codeFam Zheng1-25/+0
The block layer will handle the unaligned request. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-06-04dataplane: Support VIRTIO_BLK_T_SCSI_CMDFam Zheng1-8/+10
Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04virtio-blk: Allow config-wce in dataplaneFam Zheng1-6/+0
Dataplane now uses block layer. Protect bdrv_set_enable_write_cache with aio_context_acquire and aio_context_release, so we can enable config-wce to allow guest to modify the write cache online. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04dataplane: implement async flushStefan Hajnoczi1-16/+27
Stop using the raw-posix file descriptor for synchronous qemu_fdatasync(). Use bdrv_aio_flush() instead and drop the VirtIOBlockDataPlane->fd field. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04dataplane: delete IOQueue since it is no longer usedStefan Hajnoczi3-175/+1
This custom Linux AIO request queue is no longer used by virtio-blk data-plane. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04dataplane: use the QEMU block layer for I/OStefan Hajnoczi1-128/+65
Stop using a custom Linux AIO request queue from ioq.h and instead use the QEMU block layer for I/O. This patch adjusts the VirtIOBlockRequest struct with fields needed for bdrv_aio_readv()/bdrv_aio_writev(). ioq.h used struct iovec and struct iocb, which we don't need directly anymore. Modify dataplane start/stop to set the AioContext on the BlockDriverState. We also no longer need to get the raw-posix file descriptor. This means image formats are now supported with dataplane! Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-05-28block: Replace in_use with operation blockerFam Zheng1-6/+12
This drops BlockDriverState.in_use with op_blockers: - Call bdrv_op_block_all in place of bdrv_set_in_use(bs, 1). - Call bdrv_op_unblock_all in place of bdrv_set_in_use(bs, 0). - Check bdrv_op_is_blocked() in place of bdrv_in_use(bs). The specific types are used, e.g. in place of starting block backup, bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP, ...). There is one exception in block_job_create, where bdrv_op_blocker_is_empty() is used, because we don't know the operation type here. This doesn't matter because in a few commits away we will drop the check and move it to callers that _do_ know the type. - Check bdrv_op_blocker_is_empty() in place of assert(!bs->in_use). Note: there is only bdrv_op_block_all and bdrv_op_unblock_all callers at this moment. So although the checks are specific to op types, this changes can still be seen as identical logic with previously with in_use. The difference is error message are improved because of blocker error info. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-04-04dataplane: replace iothread object_add() with embedded instanceStefan Hajnoczi1-19/+12
Before IOThread was its own object, each virtio-blk device would create its own internal thread. We need to preserve this behavior for backwards compatibility when users do not specify -device virtio-blk-pci,iothread=<id>. This patch changes how the internal IOThread object is created. Previously we used the monitor object_add() function, which is really a layering violation. The problem is that this needs to assign a name but we don't have a name for this internal object. Generating names for internal objects is a pain but even worse is that they may collide with user-defined names. Paolo Bonzini <pbonzini@redhat.com> suggested that the internal IOThread object should not be named. This way the conflict cannot happen and we no longer need object_add(). One gotcha is that internal IOThread objects will not be listed by the query-iothreads command since they are not named. This is okay though because query-iothreads is new and the internal IOThread is just for backwards compatibility. New users should explicitly define IOThread objects. Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-03-19dataplane: fix implicit IOThread refcountStefan Hajnoczi1-1/+1
When creating an IOThread implicitly (the user did not specify x-iothread=<id>) remember that iothread_find() does not return the object with an incremented refcount. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-03-13dataplane: replace internal thread with IOThreadStefan Hajnoczi1-42/+54
Today virtio-blk dataplane uses a 1:1 device-per-thread model. Now that IOThreads have been introduced we can generalize this to N:M devices per threads. This patch drops thread code from dataplane in favor of running inside an IOThread AioContext. As a bonus we solve the case where a guest keeps submitting I/O requests while dataplane is trying to stop. Previously the dataplane thread would continue to process requests until the request gave it a break. Now we can shut down in bounded time thanks to aio_context_acquire/release. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-09Add a 'name' parameter to qemu_thread_createDr. David Alan Gilbert1-1/+1
If enabled, set the thread name at creation (on GNU systems with pthread_set_np) Fix up all the callers with a thread name Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
2014-01-31dataplane: Comment fixMarkus Armbruster1-1/+1
Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-20dataplane: change vring API to use VirtQueueElementPaolo Bonzini1-52/+33
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-20vring: factor common code for error exitsPaolo Bonzini1-0/+1
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-09virtio-blk-dataplane: Improve error reportingAndreas Färber2-16/+19
Return an Error so that it can be propagated later. Tested-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> [AF: Rebased] Signed-off-by: Andreas Färber <afaerber@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-09-06dataplane: Fix startup race.Cornelia Huck1-0/+9
Avoid trying to setup dataplane again if dataplane setup is already in progress. This may happen if an eventfd is triggered during setup. I saw this occasionally with an experimental s390 irqfd implementation: virtio_blk_handle_output -> virtio_blk_data_plane_start -> virtio_ccw_set_host_notifier ... -> virtio_queue_set_host_notifier_fd_handler -> virtio_queue_host_notifier_read -> virtio_queue_notify_vq -> virtio_blk_handle_output -> virtio_blk_data_plane_start -> vring_setup -> hostmem_init -> memory_listener_register -> BOOM As virtio-ccw tries to follow what virtio-pci does, it might be triggerable for other platforms as well. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-19aio: drop io_flush argumentStefan Hajnoczi1-4/+4
The .io_flush() handler no longer exists and has no users. Drop the io_flush argument to aio_set_fd_handler() and related functions. The AioFlushEventNotifierHandler and AioFlushHandler typedefs are no longer used and are dropped too. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-19dataplane/virtio-blk: drop flush_true() and flush_io()Stefan Hajnoczi1-15/+2
.io_flush() is no longer called so drop flush_true() and flush_io(). Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-19dataplane/virtio-blk: check exit conditions before aio_poll()Stefan Hajnoczi1-2/+2
Check exit conditions before entering blocking aio_poll(). This is mainly for consistency since it's unlikely that we are stopping in the first event loop iteration. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-07-29dataplane: refuse to start if device is already in useStefan Hajnoczi1-0/+8
Dataplane must check whether a block device is in use before launching the dataplane thread. This is necessary since the thread does not synchronize with the main loop and I/O requests could cause corruption. One example is when a drive is added and a block job is started before hotplugging the virtio-blk-pci adapter. In this case we must not use dataplane mode. Cc: qemu-stable@nongnu.org Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-07-29dataplane: enable virtio-blk x-data-plane=on live migrationStefan Hajnoczi1-9/+0
Although the dataplane thread does not cooperate with dirty memory logging yet it's fairly easy to temporarily disable dataplane during live migration. This way virtio-blk can live migrate when x-data-plane=on. The dataplane thread will restart after migration is cancelled or if the guest resuming virtio-blk operation after migration completes. Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>