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2024-01-08Rename "QEMU global mutex" to "BQL" in comments and docsStefan Hajnoczi1-3/+3
The term "QEMU global mutex" is identical to the more widely used Big QEMU Lock ("BQL"). Update the code comments and documentation to use "BQL" instead of "QEMU global mutex". Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Paul Durrant <paul@xen.org> Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com> Message-id: 20240102153529.486531-6-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-12-21virtio-scsi: don't lock AioContext around ↵Stefan Hajnoczi1-7/+1
virtio_queue_aio_attach_host_notifier() virtio_queue_aio_attach_host_notifier() does not require the AioContext lock. Stop taking the lock and add an explicit smp_wmb() because we were relying on the implicit barrier in the AioContext lock before. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-ID: <20231204164259.1515217-3-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-06-23hw/virtio: Remove unnecessary 'virtio-access.h' headerPhilippe Mathieu-Daudé1-1/+0
None of these files use the VirtIO Load/Store API declared by "hw/virtio/virtio-access.h". This header probably crept in via copy/pasting, remove it. Note, "virtio-access.h" is target-specific, so any file including it also become tainted as target-specific. Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> Acked-by: Richard Henderson <richard.henderson@linaro.org> Tested-by: Thomas Huth <thuth@redhat.com> Message-Id: <20230524093744.88442-10-philmd@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
2023-05-30virtio-scsi: implement BlockDevOps->drained_begin()Stefan Hajnoczi1-7/+11
The virtio-scsi Host Bus Adapter provides access to devices on a SCSI bus. Those SCSI devices typically have a BlockBackend. When the BlockBackend enters a drained section, the SCSI device must temporarily stop submitting new I/O requests. Implement this behavior by temporarily stopping virtio-scsi virtqueue processing when one of the SCSI devices enters a drained section. The new scsi_device_drained_begin() API allows scsi-disk to message the virtio-scsi HBA. scsi_device_drained_begin() uses a drain counter so that multiple SCSI devices can have overlapping drained sections. The HBA only sees one pair of .drained_begin/end() calls. After this commit, virtio-scsi no longer depends on hw/virtio's ioeventfd aio_set_event_notifier(is_external=true). This commit is a step towards removing the aio_disable_external() API. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230516190238.8401-19-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-05-30virtio: make it possible to detach host notifier from any threadStefan Hajnoczi1-0/+14
virtio_queue_aio_detach_host_notifier() does two things: 1. It removes the fd handler from the event loop. 2. It processes the virtqueue one last time. The first step can be peformed by any thread and without taking the AioContext lock. The second step may need the AioContext lock (depending on the device implementation) and runs in the thread where request processing takes place. virtio-blk and virtio-scsi therefore call virtio_queue_aio_detach_host_notifier() from a BH that is scheduled in AioContext. The next patch will introduce a .drained_begin() function that needs to call virtio_queue_aio_detach_host_notifier(). .drained_begin() functions cannot call aio_poll() to wait synchronously for the BH. It is possible for a .drained_poll() callback to asynchronously wait for the BH, but that is more complex than necessary here. Move the virtqueue processing out to the callers of virtio_queue_aio_detach_host_notifier() so that the function can be called from any thread. This is in preparation for the next patch. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230516190238.8401-17-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-05-10aio-wait: avoid AioContext lock in aio_wait_bh_oneshot()Stefan Hajnoczi1-2/+0
There is no need for the AioContext lock in aio_wait_bh_oneshot(). It's easy to remove the lock from existing callers and then switch from AIO_WAIT_WHILE() to AIO_WAIT_WHILE_UNLOCKED() in aio_wait_bh_oneshot(). Document that the AioContext lock should not be held across aio_wait_bh_oneshot(). Holding a lock across aio_poll() can cause deadlock so we don't want callers to do that. This is a step towards getting rid of the AioContext lock. Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230404153307.458883-1-stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-08-17virtio-scsi: fix race in virtio_scsi_dataplane_start()Stefan Hajnoczi1-3/+8
As soon as virtio_scsi_data_plane_start() attaches host notifiers the IOThread may start virtqueue processing. There is a race between IOThread virtqueue processing and virtio_scsi_data_plane_start() because it only assigns s->dataplane_started after attaching host notifiers. When a virtqueue handler function in the IOThread calls virtio_scsi_defer_to_dataplane() it may see !s->dataplane_started and attempt to start dataplane even though we're already in the IOThread: #0 0x00007f67b360857c __pthread_kill_implementation (libc.so.6 + 0xa257c) #1 0x00007f67b35bbd56 raise (libc.so.6 + 0x55d56) #2 0x00007f67b358e833 abort (libc.so.6 + 0x28833) #3 0x00007f67b358e75b __assert_fail_base.cold (libc.so.6 + 0x2875b) #4 0x00007f67b35b4cd6 __assert_fail (libc.so.6 + 0x4ecd6) #5 0x000055ca87fd411b memory_region_transaction_commit (qemu-kvm + 0x67511b) #6 0x000055ca87e17811 virtio_pci_ioeventfd_assign (qemu-kvm + 0x4b8811) #7 0x000055ca87e14836 virtio_bus_set_host_notifier (qemu-kvm + 0x4b5836) #8 0x000055ca87f8e14e virtio_scsi_set_host_notifier (qemu-kvm + 0x62f14e) #9 0x000055ca87f8dd62 virtio_scsi_dataplane_start (qemu-kvm + 0x62ed62) #10 0x000055ca87e14610 virtio_bus_start_ioeventfd (qemu-kvm + 0x4b5610) #11 0x000055ca87f8c29a virtio_scsi_handle_ctrl (qemu-kvm + 0x62d29a) #12 0x000055ca87fa5902 virtio_queue_host_notifier_read (qemu-kvm + 0x646902) #13 0x000055ca882c099e aio_dispatch_handler (qemu-kvm + 0x96199e) #14 0x000055ca882c1761 aio_poll (qemu-kvm + 0x962761) #15 0x000055ca880e1052 iothread_run (qemu-kvm + 0x782052) #16 0x000055ca882c562a qemu_thread_start (qemu-kvm + 0x96662a) This patch assigns s->dataplane_started before attaching host notifiers so that virtqueue handler functions that run in the IOThread before virtio_scsi_data_plane_start() returns correctly identify that dataplane does not need to be started. This fix is taken from the virtio-blk dataplane code and it's worth adding a comment in virtio-blk as well to explain why it works. Note that s->dataplane_started does not need the AioContext lock because it is set before attaching host notifiers and cleared after detaching host notifiers. In other words, the IOThread always sees the value true and the main loop thread does not modify it while the IOThread is active. Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2099541 Reported-by: Qing Wang <qinwang@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20220808162134.240405-1-stefanha@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-05-09virtio-scsi: don't waste CPU polling the event virtqueueStefan Hajnoczi1-1/+1
The virtio-scsi event virtqueue is not emptied by its handler function. This is typical for rx virtqueues where the device uses buffers when some event occurs (e.g. a packet is received, an error condition happens, etc). Polling non-empty virtqueues wastes CPU cycles. We are not waiting for new buffers to become available, we are waiting for an event to occur, so it's a misuse of CPU resources to poll for buffers. Introduce the new virtio_queue_aio_attach_host_notifier_no_poll() API, which is identical to virtio_queue_aio_attach_host_notifier() except that it does not poll the virtqueue. Before this patch the following command-line consumed 100% CPU in the IOThread polling and calling virtio_scsi_handle_event(): $ qemu-system-x86_64 -M accel=kvm -m 1G -cpu host \ --object iothread,id=iothread0 \ --device virtio-scsi-pci,iothread=iothread0 \ --blockdev file,filename=test.img,aio=native,cache.direct=on,node-name=drive0 \ --device scsi-hd,drive=drive0 After this patch CPU is no longer wasted. Reported-by: Nir Soffer <nsoffer@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Tested-by: Nir Soffer <nsoffer@redhat.com> Message-id: 20220427143541.119567-3-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-01-12virtio: unify dataplane and non-dataplane ->handle_output()Stefan Hajnoczi1-48/+6
Now that virtio-blk and virtio-scsi are ready, get rid of the handle_aio_output() callback. It's no longer needed. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20211207132336.36627-7-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-01-12virtio: get rid of VirtIOHandleAIOOutputStefan Hajnoczi1-12/+6
The virtqueue host notifier API virtio_queue_aio_set_host_notifier_handler() polls the virtqueue for new buffers. AioContext previously required a bool progress return value indicating whether an event was handled or not. This is no longer necessary because the AioContext polling API has been split into a poll check function and an event handler function. The event handler is only run when we know there is work to do, so it doesn't return bool. The VirtIOHandleAIOOutput function signature is now the same as VirtIOHandleOutput. Get rid of the bool return value. Further simplifications will be made for virtio-blk and virtio-scsi in the next patch. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20211207132336.36627-3-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-07-02virtio: Clarify MR transaction optimizationGreg Kurz1-0/+16
The device model batching its ioeventfds in a single MR transaction is an optimization. Clarify this in virtio-scsi, virtio-blk and generic virtio code. Also clarify that the transaction must commit before closing ioeventfds so that no one is tempted to merge the loops in the start functions error path and in the stop functions. Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <162125799728.1394228.339855768563326832.stgit@bahia.lan> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2021-05-14virtio-scsi: Configure all host notifiers in a single MR transactionGreg Kurz1-0/+16
This allows the virtio-scsi-pci device to batch the setup of all its host notifiers. This significantly improves boot time of VMs with a high number of vCPUs, e.g. from 6m5.563s down to 1m2.884s for a pseries machine with 384 vCPUs. Note that memory_region_transaction_commit() must be called before virtio_bus_cleanup_host_notifier() because the latter might close ioeventfds that the transaction still assumes to be around when it commits. Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210407143501.244343-5-groug@kaod.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2021-05-14virtio-scsi: Set host notifiers and callbacks separatelyGreg Kurz1-18/+22
Host notifiers are guaranteed to be idle until the callbacks are hooked up with virtio_queue_aio_set_host_notifier_handler(). They thus don't need to be set or unset with the AioContext lock held. Do this outside the critical section, like virtio-blk already does : basically downgrading virtio_scsi_vring_init() to only setup the host notifier and set the callback in the caller. This will allow to batch addition/deletion of ioeventds in a single memory transaction, which is expected to greatly improve initialization time. Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210407143501.244343-4-groug@kaod.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2021-02-25virtio-scsi: don't process IO on fenced dataplaneMaxim Levitsky1-9/+15
If virtio_scsi_dataplane_start fails, there is a small window when it drops the aio lock (in aio_wait_bh_oneshot) and the dataplane's AIO handler can still run during that window. This is done after the dataplane was marked as fenced, thus we use this flag to avoid it doing any IO. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20201217150040.906961-2-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-08virtio-scsi: don't uninitialize queues that we didn't initializeMaxim Levitsky1-1/+7
Count number of queues that we initialized and only deinitialize these that we initialized successfully. Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com> Message-Id: <20201217150040.906961-3-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-06-28Replace '-enable-kvm' with '-accel kvm' in docs and help textsThomas Huth1-2/+2
The preferred way to select the KVM accelerator is to use "-accel kvm" these days, so let's be consistent in our documentation and help texts. Signed-off-by: Thomas Huth <thuth@redhat.com> Message-Id: <1528866321-23886-3-git-send-email-thuth@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-03-08virtio-scsi: fix race between .ioeventfd_stop() and vq handlerStefan Hajnoczi1-4/+5
If the main loop thread invokes .ioeventfd_stop() just as the vq handler function begins in the IOThread then the handler may lose the race for the AioContext lock. By the time the vq handler is able to acquire the AioContext lock the ioeventfd has already been removed and the handler isn't supposed to run anymore! Use the new aio_wait_bh_oneshot() function to perform ioeventfd removal from within the IOThread. This way no races with the vq handler are possible. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20180307144205.20619-4-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2018-02-08virtio: remove event notifier cleanup call on de-assignGal Hammer1-0/+2
The virtio_bus_set_host_notifier function no longer calls event_notifier_cleanup when a event notifier is removed. The commit updates the code to match the new behavior and calls virtio_bus_cleanup_host_notifier after the notifier was de-assign and no longer in use. This change is a preparation to allow executing the virtio_bus_set_host_notifier function in a memory region transaction. Signed-off-by: Gal Hammer <ghammer@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org> Tested-by: Greg Kurz <groug@kaod.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2017-09-19scsi: move block/scsi.h to include/scsi/constants.hPaolo Bonzini1-1/+1
Complete the transition by renaming this header, which was shared by block/iscsi.c and the SCSI emulation code. Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-03-24virtio-scsi: Fix acquire/release in dataplane handlersFam Zheng1-4/+16
After the AioContext lock push down, there is a race between virtio_scsi_dataplane_start and those "assert(s->ctx && s->dataplane_started)", because the latter doesn't isn't wrapped in aio_context_acquire. Reproducer is simply booting a Fedora guest with an empty virtio-scsi-dataplane controller: qemu-system-x86_64 \ -drive if=none,id=root,format=raw,file=Fedora-Cloud-Base-25-1.3.x86_64.raw \ -device virtio-scsi \ -device scsi-disk,drive=root,bootindex=1 \ -object iothread,id=io \ -device virtio-scsi-pci,iothread=io \ -net user,hostfwd=tcp::10022-:22 -net nic,model=virtio -m 2048 \ --enable-kvm Fix this by moving acquire/release pairs from virtio_scsi_handle_*_vq to their callers - and wrap the broken assertions in. Signed-off-by: Fam Zheng <famz@redhat.com> Message-Id: <20170317061447.16243-3-famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-02-17virtio: Report real progress in VQ aio poll handlerFam Zheng1-7/+7
In virtio_queue_host_notifier_aio_poll, not all "!virtio_queue_empty()" cases are making true progress. Currently the offending one is virtio-scsi event queue, whose handler does nothing if no event is pending. As a result aio_poll() will spin on the "non-empty" VQ and take 100% host CPU. Fix this by reporting actual progress from virtio queue aio handlers. Reported-by: Ed Swierk <eswierk@skyportsystems.com> Signed-off-by: Fam Zheng <famz@redhat.com> Tested-by: Ed Swierk <eswierk@skyportsystems.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-11-18virtio: set ISR on dataplane notificationsPaolo Bonzini1-7/+0
Dataplane has been omitting forever the step of setting ISR when an interrupt is raised. This caused little breakage, because the specification actually says that ISR may not be updated in MSI mode. Some versions of the Windows drivers however didn't clear MSI mode correctly, and proceeded using polling mode (using ISR, not the used ring index!) for crashdump and hibernation. If it were just crashdump and hibernation it would not be a big deal, but recent releases of Windows do not really shut down, but rather log out and hibernate to make the next startup faster. Hence, this manifested as a more serious hang during shutdown with e.g. Windows 8.1 and virtio-win 1.8.0 RPMs. Newer versions fixed this, while older versions do not use MSI at all. The failure has always been there for virtio dataplane, but it became visible after commits 9ffe337 ("virtio-blk: always use dataplane path if ioeventfd is active", 2016-10-30) and ad07cd6 ("virtio-scsi: always use dataplane path if ioeventfd is active", 2016-10-30) made virtio-blk and virtio-scsi always use the dataplane code under KVM. The good news therefore is that it was not a bug in the patches---they were doing exactly what they were meant for, i.e. shake out remaining dataplane bugs. The fix is not hard, so it's worth arranging for the broken drivers. The virtio_should_notify+event_notifier_set pair that is common to virtio-blk and virtio-scsi dataplane is replaced with a new public function virtio_notify_irqfd that also sets ISR. The irqfd emulation code now need not set ISR anymore, so virtio_irq is removed. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Tested-by: Farhan Ali <alifm@linux.vnet.ibm.com> Tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-11-03Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into stagingStefan Hajnoczi1-22/+34
virtio, pc: fixes and features nvdimm hotplug support virtio migration and ioeventfd rework virtio crypto device ipmi fixes Signed-off-by: Michael S. Tsirkin <mst@redhat.com> # gpg: Signature made Tue 01 Nov 2016 05:23:40 PM GMT # gpg: using RSA key 0x281F0DB8D28D5469 # gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" # gpg: aka "Michael S. Tsirkin <mst@redhat.com>" # Primary key fingerprint: 0270 606B 6F3C DF3D 0B17 0970 C350 3912 AFBE 8E67 # Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA 8A0D 281F 0DB8 D28D 5469 * remotes/mst/tags/for_upstream: (47 commits) acpi: fix assert failure caused by commit 35c5a52d acpi/ipmi: Initialize the fwinfo before fetching it ipmi: Add graceful shutdown handling to the external BMC ipmi: fix build config variable name for ipmi_bmc_extern.o ipmi: Implement shutdown via ACPI overtemp ipmi: chassis poweroff should use qemu_system_shutdown_request() ipmi_bmc_sim: Remove an unnecessary mutex ipmi: Remove hotplug from IPMI BMCs pc: memhp: enable nvdimm device hotplug nvdimm acpi: introduce _FIT nvdimm acpi: introduce fit buffer nvdimm acpi: prebuild nvdimm devices for available slots nvdimm acpi: use common macros instead of magic names acpi nvdimm: rename result_size to dsm_out_buf_siz nvdimm acpi: compile nvdimm acpi code arch-independently acpi nvdimm: fix Arg6 usage acpi nvdimm: fix ARG3 conflict acpi nvdimm: fix device physical address base acpi nvdimm: fix OperationRegion definition acpi nvdimm: fix wrong buffer size returned by DSM method ... Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-30virtio-scsi: always use dataplane path if ioeventfd is activePaolo Bonzini1-22/+34
Override start_ioeventfd and stop_ioeventfd to start/stop the whole dataplane logic. This has some positive side effects: - no need anymore for virtio_add_queue_aio (i.e. a revert of commit 1c627137c10ee2dcf59e0383ade8a9abfa2d4355) - no need anymore to switch from generic ioeventfd handlers to dataplane It detects some errors better: $ qemu-system-x86_64 -object iothread,id=io \ -device virtio-scsi-pci,ioeventfd=off,iothread=io qemu-system-x86_64: -device virtio-scsi-pci,ioeventfd=off,iothread=io: ioeventfd is required for iothread while previously it would have started just fine. Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-10-30virtio: move ioeventfd_started flag to VirtioBusStatePaolo Bonzini1-1/+1
This simplifies the code and removes the ioeventfd_started and ioeventfd_set_started callback. The only difference is in how virtio-ccw handles an error---it doesn't disable ioeventfd forever anymore. It was the only backend to do so, and if desired this behavior should be implemented in virtio-bus.c. Instead of ioeventfd_started, the ioeventfd_assign callback now determines whether the virtio bus supports host notifiers. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-10-28block: only call aio_poll on the current thread's AioContextPaolo Bonzini1-3/+1
aio_poll is not thread safe; for example bdrv_drain can hang if the last in-flight I/O operation is completed in the I/O thread after the main thread has checked bs->in_flight. The bug remains latent as long as all of it is called within aio_context_acquire/aio_context_release, but this will change soon. To fix this, if bdrv_drain is called from outside the I/O thread, signal the main AioContext through a dummy bottom half. The event loop then only runs in the I/O thread. Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <1477565348-5458-18-git-send-email-pbonzini@redhat.com> Signed-off-by: Fam Zheng <famz@redhat.com>
2016-07-12Use #include "..." for our own headers, <...> for othersMarkus Armbruster1-3/+3
Tracked down with an ugly, brittle and probably buggy Perl script. Also move includes converted to <...> up so they get included before ours where that's obviously okay. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Tested-by: Eric Blake <eblake@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-06-24virtio-bus: remove old set_host_notifier callbackCornelia Huck1-15/+4
All users have been converted to the new ioevent callbacks. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-06-24virtio-bus: have callers tolerate new host notifier apiCornelia Huck1-5/+15
Have vhost and dataplane use the new api for transports that have been converted. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-04-07virtio: merge virtio_queue_aio_set_host_notifier_handler with ↵Paolo Bonzini1-8/+4
virtio_queue_set_aio Eliminating the reentrancy is actually a nice thing that we can do with the API that Michael proposed, so let's make it first class. This also hides the complex assign/set_handler conventions from callers of virtio_queue_aio_set_host_notifier_handler, which in fact was always called with assign=true. Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-04-07virtio-scsi: use aio handler for data planePaolo Bonzini1-4/+39
In addition to handling IO in vcpu thread and in io thread, dataplane introduces yet another mode: handling it by AioContext. This reuses the same handler as previous modes, which triggers races as these were not designed to be reentrant. Use a separate handler just for aio, and disable regular handlers when dataplane is active. Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-03-22Clean up includes some moreMarkus Armbruster1-1/+0
Manually drop redundant includes that scripts/clean-includes misses, e.g. because they're hidden in generator programs, or they use the wrong kind of delimiter. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-02-25virtio-scsi: do not use vring in dataplanePaolo Bonzini1-171/+25
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-02-06virtio: move allocation to virtqueue_pop/vring_popPaolo Bonzini1-7/+8
The return code of virtqueue_pop/vring_pop is unused except to check for errors or 0. We can thus easily move allocation inside the functions and just return a pointer to the VirtQueueElement. The advantage is that we will be able to allocate only the space that is needed for the actual size of the s/g list instead of the full VIRTQUEUE_MAX_SIZE items. Currently VirtQueueElement takes about 48K of memory, and this kind of allocation puts a lot of stress on malloc. By cutting the size by two or three orders of magnitude, malloc can use much more efficient algorithms. The patch is pretty large, but changes to each device are testable more or less independently. Splitting it would mostly add churn. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2016-01-29virtio: Clean up includesPeter Maydell1-0/+1
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1453832250-766-15-git-send-email-peter.maydell@linaro.org
2015-10-23dataplane: Mark host notifiers' client type as "external"Fam Zheng1-10/+8
They will be excluded by type in the nested event loops in block layer, so that unwanted events won't be processed there. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23aio: Add "is_external" flag for event handlersFam Zheng1-8/+16
All callers pass in false, and the real external ones will switch to true in coming patches. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-12scsi: switch from g_slice allocator to mallocPaolo Bonzini1-5/+5
Simplify memory allocation by sticking with a single API. GSlice is not that fast anyway (tcmalloc/jemalloc are better). Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-26virtio-scsi-dataplane: fix memory leak for VirtIOSCSIVringTing Wang1-0/+6
VirtIOSCSIVring which allocated in virtio_scsi_vring_init should be free when dataplane has been stopped or failed to start. Signed-off-by: Ting Wang <kathy.wangting@huawei.com> Message-Id: <1427355752-25844-1-git-send-email-kathy.wangting@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-18virtio-scsi-dataplane: fix memory leak in virtio_scsi_vring_initBo Su1-1/+3
if k->set_host_notifier failed, VirtIOSCSIVring *r will leak Signed-off-by: Bo Su <subo7@huawei.com> Message-Id: <1426671732-80213-1-git-send-email-subo7@huawei.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Gonglei <arei.gonglei@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-02virtio-scsi: Allocate op blocker reason before blockingMax Reitz1-4/+0
s->blocker is really only used in hw/scsi/virtio-scsi.c; the only places where it is used in hw/scsi/virtio-scsi-dataplane.c is when it is allocated and when it is freed. That does not make a whole lot of sense (and is actually wrong because this leads to s->blocker potentially being NULL when blk_op_block_all() is called in virtio-scsi.c), so move the allocation and destruction of s->blocker to the device realization and unrealization in virtio-scsi.c, respectively. Case in point: $ echo -e 'eject drv\nquit' | \ x86_64-softmmu/qemu-system-x86_64 \ -monitor stdio -machine accel=qtest -display none \ -object iothread,id=thr -device virtio-scsi-pci,iothread=thr \ -drive if=none,file=test.qcow2,format=qcow2,id=drv \ -device scsi-cd,drive=drv Without this patch: (qemu) eject drv [1] 10102 done 10103 segmentation fault (core dumped) With this patch: (qemu) eject drv Device 'drv' is busy: block device is in use by data plane (qemu) quit Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <1425057113-26940-1-git-send-email-mreitz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-02-16dataplane: endianness-aware accessesCornelia Huck1-1/+1
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>
2014-11-12virtio-scsi: dataplane: suppress guest notificationMing Lei1-1/+6
This patch uses vring_should_notify() to suppress guest notification, and looks notification frequency can be decreased from ~33K/sec to ~2K/sec in my test environment. Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-11-11virtio-scsi: dataplane: fix allocation for 'cmd_vrings'Ming Lei1-1/+1
The size of each element should be sizeof(VirtIOSCSIVring *). Signed-off-by: Ming Lei <ming.lei@canonical.com> Reviewed-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-31virtio-scsi: fix dataplanePaolo Bonzini1-1/+2
Commit 361dcc7 (virtio-scsi: dataplane: fail setup gracefully, 2014-10-15) actually broke successful dataplane setup in a not-so-graceful manner: qemu-system-x86_64: .../util/rfifolock.c:71: rfifolock_unlock: Assertion `r->nesting > 0' failed. due to a missing return statement. Fixes: 361dcc790db8c87b2e46ab610739191ced894c44 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-23virtio-scsi: dataplane: stop trying on notifier errorCornelia Huck1-0/+8
There's no use to constantly trying to enable dataplane if we failed to set up guest or host notifiers, so fence it off in that case. We'll try again if the device is reinitialized. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-23virtio-scsi: dataplane: fail setup gracefullyCornelia Huck1-9/+70
The dataplane code is currently doing a hard exit on various setup failures. 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 the nth device). Let's just try to unwind the setup instead and return. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-23virtio-scsi: dataplane: print why starting failedCornelia Huck1-4/+7
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. Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-23virtio-scsi-dataplane: Add op blockerFam Zheng1-0/+4
We need this to protect dataplane thread from race conditions with block jobs until the latter is made dataplane-safe. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-10-20hw: Convert from BlockDriverState to BlockBackend, mostlyMarkus Armbruster1-1/+2
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>
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