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2024-01-26virtio-blk: move dataplane code into virtio-blk.cStefan Hajnoczi
The dataplane code used to be significantly different from the non-dataplane code and therefore had a separate source file. Over time the difference has gotten smaller because the I/O code paths were unified. Nowadays the distinction between the VirtIOBlock and VirtIOBlockDataPlane structs is more of an inconvenience that hinders code simplification. Move hw/block/dataplane/virtio-blk.c into hw/block/virtio-blk.c, merging VirtIOBlockDataPlane's fields into VirtIOBlock. hw/block/virtio-blk.c used VirtIOBlock->dataplane to check if virtio_blk_data_plane_create() was successful. This is not necessary because ->dataplane_started and ->dataplane_disabled can be used instead. This patch makes those changes in order to drop VirtIOBlock->dataplane. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20240119135748.270944-2-stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2024-01-08Rename "QEMU global mutex" to "BQL" in comments and docsStefan Hajnoczi
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>
2023-12-25virtio-blk: Fix potential nullpointer read access in ↵Stefan Weil via
virtio_blk_data_plane_destroy Fixes: CID 1532828 Fixes: b6948ab01d ("virtio-blk: add iothread-vq-mapping parameter") Signed-off-by: Stefan Weil <sw@weilnetz.de> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2023-12-21virtio-blk: add iothread-vq-mapping parameterStefan Hajnoczi
Add the iothread-vq-mapping parameter to assign virtqueues to IOThreads. Store the vq:AioContext mapping in the new struct VirtIOBlockDataPlane->vq_aio_context[] field and refactor the code to use the per-vq AioContext instead of the BlockDriverState's AioContext. Reimplement --device virtio-blk-pci,iothread= and non-IOThread mode by assigning all virtqueues to the IOThread and main loop's AioContext in vq_aio_context[], respectively. The comment in struct VirtIOBlockDataPlane about EventNotifiers is stale. Remove it. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20231220134755.814917-5-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-12-21block: remove AioContext lockingStefan Hajnoczi
This is the big patch that removes aio_context_acquire()/aio_context_release() from the block layer and affected block layer users. There isn't a clean way to split this patch and the reviewers are likely the same group of people, so I decided to do it in one patch. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Paul Durrant <paul@xen.org> Message-ID: <20231205182011.1976568-7-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-31virtio-blk: remove batch notification BHStefan Hajnoczi
There is a batching mechanism for virtio-blk Used Buffer Notifications that is no longer needed because the previous commit added batching to virtio_notify_irqfd(). Note that this mechanism was rarely used in practice because it is only enabled when EVENT_IDX is not negotiated by the driver. Modern drivers enable EVENT_IDX. Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230913200045.1024233-5-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-31util/defer-call: move defer_call() to util/Stefan Hajnoczi
The networking subsystem may wish to use defer_call(), so move the code to util/ where it can be reused. As a reminder of what defer_call() does: This API defers a function call within a defer_call_begin()/defer_call_end() section, allowing multiple calls to batch up. This is a performance optimization that is used in the block layer to submit several I/O requests at once instead of individually: defer_call_begin(); <-- start of section ... defer_call(my_func, my_obj); <-- deferred my_func(my_obj) call defer_call(my_func, my_obj); <-- another defer_call(my_func, my_obj); <-- another ... defer_call_end(); <-- end of section, my_func(my_obj) is called once Suggested-by: Ilya Maximets <i.maximets@ovn.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230913200045.1024233-3-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-10-31block: rename blk_io_plug_call() API to defer_call()Stefan Hajnoczi
Prepare to move the blk_io_plug_call() API out of the block layer so that other subsystems call use this deferred call mechanism. Rename it to defer_call() but leave the code in block/plug.c. The next commit will move the code out of the block layer. Suggested-by: Ilya Maximets <i.maximets@ovn.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Paul Durrant <paul@xen.org> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20230913200045.1024233-2-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-07-12virtio-blk: fix host notifier issues during dataplane start/stopStefan Hajnoczi
The main loop thread can consume 100% CPU when using --device virtio-blk-pci,iothread=<iothread>. ppoll() constantly returns but reading virtqueue host notifiers fails with EAGAIN. The file descriptors are stale and remain registered with the AioContext because of bugs in the virtio-blk dataplane start/stop code. The problem is that the dataplane start/stop code involves drain operations, which call virtio_blk_drained_begin() and virtio_blk_drained_end() at points where the host notifier is not operational: - In virtio_blk_data_plane_start(), blk_set_aio_context() drains after vblk->dataplane_started has been set to true but the host notifier has not been attached yet. - In virtio_blk_data_plane_stop(), blk_drain() and blk_set_aio_context() drain after the host notifier has already been detached but with vblk->dataplane_started still set to true. I would like to simplify ->ioeventfd_start/stop() to avoid interactions with drain entirely, but couldn't find a way to do that. Instead, this patch accepts the fragile nature of the code and reorders it so that vblk->dataplane_started is false during drain operations. This way the virtio_blk_drained_begin() and virtio_blk_drained_end() calls don't touch the host notifier. The result is that virtio_blk_data_plane_start() and virtio_blk_data_plane_stop() have complete control over the host notifier and stale file descriptors are no longer left in the AioContext. This patch fixes the 100% CPU consumption in the main loop thread and correctly moves host notifier processing to the IOThread. Fixes: 1665d9326fd2 ("virtio-blk: implement BlockDevOps->drained_begin()") Reported-by: Lukáš Doktor <ldoktor@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Tested-by: Lukas Doktor <ldoktor@redhat.com> Message-id: 20230704151527.193586-1-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-06-23hw/virtio: Build various target-agnostic objects just oncePhilippe Mathieu-Daudé
The previous commit remove the unnecessary "virtio-access.h" header. These files no longer have target-specific dependency. Move them to the generic 'softmmu_ss' source set. Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Thomas Huth <thuth@redhat.com> Message-Id: <20230524093744.88442-11-philmd@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-06-23hw/virtio: Remove unnecessary 'virtio-access.h' headerPhilippe Mathieu-Daudé
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>
2023-06-01block: add blk_io_plug_call() APIStefan Hajnoczi
Introduce a new API for thread-local blk_io_plug() that does not traverse the block graph. The goal is to make blk_io_plug() multi-queue friendly. Instead of having block drivers track whether or not we're in a plugged section, provide an API that allows them to defer a function call until we're unplugged: blk_io_plug_call(fn, opaque). If blk_io_plug_call() is called multiple times with the same fn/opaque pair, then fn() is only called once at the end of the function - resulting in batching. This patch introduces the API and changes blk_io_plug()/blk_io_unplug(). blk_io_plug()/blk_io_unplug() no longer require a BlockBackend argument because the plug state is now thread-local. Later patches convert block drivers to blk_io_plug_call() and then we can finally remove .bdrv_co_io_plug() once all block drivers have been converted. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Acked-by: Kevin Wolf <kwolf@redhat.com> Message-id: 20230530180959.1108766-2-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2023-05-30virtio-blk: implement BlockDevOps->drained_begin()Stefan Hajnoczi
Detach ioeventfds during drained sections to stop I/O submission from the guest. virtio-blk is no longer reliant on aio_disable_external() after this patch. This will allow us to remove the aio_disable_external() API once all other code that relies on it is converted. Take extra care to avoid attaching/detaching ioeventfds if the data plane is started/stopped during a drained section. This should be rare, but maybe the mirror block job can trigger it. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230516190238.8401-18-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-05-30virtio: make it possible to detach host notifier from any threadStefan Hajnoczi
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>
2023-05-30xen-block: implement BlockDevOps->drained_begin()Stefan Hajnoczi
Detach event channels during drained sections to stop I/O submission from the ring. xen-block is no longer reliant on aio_disable_external() after this patch. This will allow us to remove the aio_disable_external() API once all other code that relies on it is converted. Extend xen_device_set_event_channel_context() to allow ctx=NULL. The event channel still exists but the event loop does not monitor the file descriptor. Event channel processing can resume by calling xen_device_set_event_channel_context() with a non-NULL ctx. Factor out xen_device_set_event_channel_context() calls in hw/block/dataplane/xen-block.c into attach/detach helper functions. Incidentally, these don't require the AioContext lock because aio_set_fd_handler() is thread-safe. It's safer to register BlockDevOps after the dataplane instance has been created. The BlockDevOps .drained_begin/end() callbacks depend on the dataplane instance, so move the blk_set_dev_ops() call after xen_block_dataplane_create(). Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20230516190238.8401-12-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-05-10aio-wait: avoid AioContext lock in aio_wait_bh_oneshot()Stefan Hajnoczi
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>
2023-04-28hw: replace most qemu_bh_new calls with qemu_bh_new_guardedAlexander Bulekov
This protects devices from bh->mmio reentrancy issues. Thanks: Thomas Huth <thuth@redhat.com> for diagnosing OS X test failure. Signed-off-by: Alexander Bulekov <alxndr@bu.edu> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Paul Durrant <paul@xen.org> Reviewed-by: Thomas Huth <thuth@redhat.com> Message-Id: <20230427211013.2994127-5-alxndr@bu.edu> Signed-off-by: Thomas Huth <thuth@redhat.com>
2023-03-07hw/xen: Build PV backend drivers for CONFIG_XEN_BUSDavid Woodhouse
Now that we have the redirectable Xen backend operations we can build the PV backends even without the Xen libraries. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-07hw/xen: Rename xen_common.h to xen_native.hDavid Woodhouse
This header is now only for native Xen code, not PV backends that may be used in Xen emulation. Since the toolstack libraries may depend on the specific version of Xen headers that they pull in (and will set the __XEN_TOOLS__ macro to enable internal definitions that they depend on), the rule is that xen_native.h (and thus the toolstack library headers) must be included *before* any of the headers in include/hw/xen/interface. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-07hw/xen: Use XEN_PAGE_SIZE in PV backend driversDavid Woodhouse
XC_PAGE_SIZE comes from the actual Xen libraries, while XEN_PAGE_SIZE is provided by QEMU itself in xen_backend_ops.h. For backends which may be built for emulation mode, use the latter. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-03-07hw/xen: Pass grant ref to gnttab unmap operationDavid Woodhouse
The previous commit introduced redirectable gnttab operations fairly much like-for-like, with the exception of the extra arguments to the ->open() call which were always NULL/0 anyway. This *changes* the arguments to the ->unmap() operation to include the original ref# that was mapped. Under real Xen it isn't necessary; all we need to do from QEMU is munmap(), then the kernel will release the grant, and Xen does the tracking/refcounting for the guest. When we have emulated grant tables though, we need to do all that for ourselves. So let's have the back ends keep track of what they mapped and pass it in to the ->unmap() method for us. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Reviewed-by: Paul Durrant <paul@xen.org>
2023-01-23virtio-blk: simplify virtio_blk_dma_restart_cb()Stefan Hajnoczi
virtio_blk_dma_restart_cb() is tricky because the BH must deal with virtio_blk_data_plane_start()/virtio_blk_data_plane_stop() being called. There are two issues with the code: 1. virtio_blk_realize() should use qdev_add_vm_change_state_handler() instead of qemu_add_vm_change_state_handler(). This ensures the ordering with virtio_init()'s vm change state handler that calls virtio_blk_data_plane_start()/virtio_blk_data_plane_stop() is well-defined. Then blk's AioContext is guaranteed to be up-to-date in virtio_blk_dma_restart_cb() and it's no longer necessary to have a special case for virtio_blk_data_plane_start(). 2. Only blk_drain() waits for virtio_blk_dma_restart_cb()'s blk_inc_in_flight() to be decremented. The bdrv_drain() family of functions do not wait for BlockBackend's in_flight counter to reach zero. virtio_blk_data_plane_stop() relies on blk_set_aio_context()'s implicit drain, but that's a bdrv_drain() and not a blk_drain(). Note that virtio_blk_reset() already correctly relies on blk_drain(). If virtio_blk_data_plane_stop() switches to blk_drain() then we can properly wait for pending virtio_blk_dma_restart_bh() calls. Once these issues are taken care of the code becomes simpler. This change is in preparation for multiple IOThreads in virtio-blk where we need to clean up the multi-threading behavior. I ran the reproducer from commit 49b44549ace7 ("virtio-blk: On restart, process queued requests in the proper context") to check that there is no regression. Cc: Sergio Lopez <slp@redhat.com> Cc: Kevin Wolf <kwolf@redhat.com> Cc: Emanuele Giuseppe Esposito <eesposit@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com> Message-id: 20221102182337.252202-1-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-08-17virtio-scsi: fix race in virtio_scsi_dataplane_start()Stefan Hajnoczi
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>
2022-03-07osdep: Move memalign-related functions to their own headerPeter Maydell
Move the various memalign-related functions out of osdep.h and into their own header, which we include only where they are used. While we're doing this, add some brief documentation comments. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20220226180723.1706285-10-peter.maydell@linaro.org
2022-01-12virtio: unify dataplane and non-dataplane ->handle_output()Stefan Hajnoczi
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 Hajnoczi
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>
2021-12-06virtio-blk: Fix clean up of host notifiers for single MR transaction.Mark Mielke
The code that introduced "virtio-blk: Configure all host notifiers in a single MR transaction" introduced a second loop variable to perform cleanup in second loop, but mistakenly still refers to the first loop variable within the second loop body. Fixes: d0267da61489 ("virtio-blk: Configure all host notifiers in a single MR transaction") Signed-off-by: Mark Mielke <mark.mielke@gmail.com> Message-id: CALm7yL08qarOu0dnQkTN+pa=BSRC92g31YpQQNDeAiT4yLZWQQ@mail.gmail.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-07-02virtio: Clarify MR transaction optimizationGreg Kurz
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>
2021-06-02docs: fix references to docs/devel/tracing.rstStefano Garzarella
Commit e50caf4a5c ("tracing: convert documentation to rST") converted docs/devel/tracing.txt to docs/devel/tracing.rst. We still have several references to the old file, so let's fix them with the following command: sed -i s/tracing.txt/tracing.rst/ $(git grep -l docs/devel/tracing.txt) Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20210517151702.109066-2-sgarzare@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2021-05-14virtio-blk: Configure all host notifiers in a single MR transactionGreg Kurz
This allows the virtio-blk-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 3m26.186s down to 0m58.023s 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: <20210407143501.244343-3-groug@kaod.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2021-05-14virtio-blk: Fix rollback path in virtio_blk_data_plane_start()Greg Kurz
When dataplane multiqueue support was added in QEMU 2.7, the path that would rollback guest notifiers assignment in case of error simply got dropped. Later on, when Error was added to blk_set_aio_context() in QEMU 4.1, another error path was introduced, but it ommits to rollback both host and guest notifiers. It seems cleaner to fix the rollback path in one go. The patch is simple enough that it can be adjusted if backported to a pre-4.1 QEMU. Fixes: 51b04ac5c6a6 ("virtio-blk: dataplane multiqueue support") Cc: stefanha@redhat.com Fixes: 97896a4887a0 ("block: Add Error to blk_set_aio_context()") Cc: kwolf@redhat.com Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210407143501.244343-2-groug@kaod.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2021-01-27block: Separate blk_is_writable() and blk_supports_write_perm()Kevin Wolf
Currently, blk_is_read_only() tells whether a given BlockBackend can only be used in read-only mode because its root node is read-only. Some callers actually try to answer a slightly different question: Is the BlockBackend configured to be writable, by taking write permissions on the root node? This can differ, for example, for CD-ROM devices which don't take write permissions, but may be backed by a writable image file. scsi-cd allows write requests to the drive if blk_is_read_only() returns false. However, the write request will immediately run into an assertion failure because the write permission is missing. This patch introduces separate functions for both questions. blk_supports_write_perm() answers the question whether the block node/image file can support writable devices, whereas blk_is_writable() tells whether the BlockBackend is currently configured to be writable. All calls of blk_is_read_only() are converted to one of the two new functions. Fixes: https://bugs.launchpad.net/bugs/1906693 Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20210118123448.307825-2-kwolf@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-01-20block: Honor blk_set_aio_context() context requirementsSergio Lopez
The documentation for bdrv_set_aio_context_ignore() states this: * The caller must own the AioContext lock for the old AioContext of bs, but it * must not own the AioContext lock for new_context (unless new_context is the * same as the current context of bs). As blk_set_aio_context() makes use of this function, this rule also applies to it. Fix all occurrences where this rule wasn't honored. Suggested-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Sergio Lopez <slp@redhat.com> Message-Id: <20201214170519.223781-2-slp@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
2020-08-21meson: convert hw/blockMarc-André Lureau
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-08-21trace: switch position of headers to what Meson requiresPaolo Bonzini
Meson doesn't enjoy the same flexibility we have with Make in choosing the include path. In particular the tracing headers are using $(build_root)/$(<D). In order to keep the include directives unchanged, the simplest solution is to generate headers with patterns like "trace/trace-audio.h" and place forwarding headers in the source tree such that for example "audio/trace.h" includes "trace/trace-audio.h". This patch is too ugly to be applied to the Makefiles now. It's only a way to separate the changes to the tracing header files from the Meson rewrite of the tracing logic. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-10xen: Use ERRP_GUARD()Vladimir Sementsov-Ogievskiy
If we want to check error after errp-function call, we need to introduce local_err and then propagate it to errp. Instead, use the ERRP_GUARD() macro, benefits are: 1. No need of explicit error_propagate call 2. No need of explicit local_err variable: use errp directly 3. ERRP_GUARD() leaves errp as is if it's not NULL or &error_fatal, this means that we don't break error_abort (we'll abort on error_set, not on error_propagate) If we want to add some info to errp (by error_prepend() or error_append_hint()), we must use the ERRP_GUARD() macro. Otherwise, this info will not be added when errp == &error_fatal (the program will exit prior to the error_append_hint() or error_prepend() call). No such cases are being fixed here. This commit is generated by command sed -n '/^X86 Xen CPUs$/,/^$/{s/^F: //p}' MAINTAINERS | \ xargs git ls-files | grep '\.[hc]$' | \ xargs spatch \ --sp-file scripts/coccinelle/errp-guard.cocci \ --macro-file scripts/cocci-macro-file.h \ --in-place --no-show-diff --max-width 80 Reported-by: Kevin Wolf <kwolf@redhat.com> Reported-by: Greg Kurz <groug@kaod.org> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> [Commit message tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20200707165037.1026246-9-armbru@redhat.com> [ERRP_AUTO_PROPAGATE() renamed to ERRP_GUARD(), and auto-propagated-errp.cocci to errp-guard.cocci. Commit message tweaked again.]
2020-06-17virtio-blk: On restart, process queued requests in the proper contextSergio Lopez
On restart, we were scheduling a BH to process queued requests, which would run before starting up the data plane, leading to those requests being assigned and started on coroutines on the main context. This could cause requests to be wrongly processed in parallel from different threads (the main thread and the iothread managing the data plane), potentially leading to multiple issues. For example, stopping and resuming a VM multiple times while the guest is generating I/O on a virtio_blk device can trigger a crash with a stack tracing looking like this one: <------> Thread 2 (Thread 0x7ff736765700 (LWP 1062503)): #0 0x00005567a13b99d6 in iov_memset (iov=0x6563617073206f4e, iov_cnt=1717922848, offset=516096, fillc=0, bytes=7018105756081554803) at util/iov.c:69 #1 0x00005567a13bab73 in qemu_iovec_memset (qiov=0x7ff73ec99748, offset=516096, fillc=0, bytes=7018105756081554803) at util/iov.c:530 #2 0x00005567a12f411c in qemu_laio_process_completion (laiocb=0x7ff6512ee6c0) at block/linux-aio.c:86 #3 0x00005567a12f42ff in qemu_laio_process_completions (s=0x7ff7182e8420) at block/linux-aio.c:217 #4 0x00005567a12f480d in ioq_submit (s=0x7ff7182e8420) at block/linux-aio.c:323 #5 0x00005567a12f43d9 in qemu_laio_process_completions_and_submit (s=0x7ff7182e8420) at block/linux-aio.c:236 #6 0x00005567a12f44c2 in qemu_laio_poll_cb (opaque=0x7ff7182e8430) at block/linux-aio.c:267 #7 0x00005567a13aed83 in run_poll_handlers_once (ctx=0x5567a2b58c70, timeout=0x7ff7367645f8) at util/aio-posix.c:520 #8 0x00005567a13aee9f in run_poll_handlers (ctx=0x5567a2b58c70, max_ns=16000, timeout=0x7ff7367645f8) at util/aio-posix.c:562 #9 0x00005567a13aefde in try_poll_mode (ctx=0x5567a2b58c70, timeout=0x7ff7367645f8) at util/aio-posix.c:597 #10 0x00005567a13af115 in aio_poll (ctx=0x5567a2b58c70, blocking=true) at util/aio-posix.c:639 #11 0x00005567a109acca in iothread_run (opaque=0x5567a2b29760) at iothread.c:75 #12 0x00005567a13b2790 in qemu_thread_start (args=0x5567a2b694c0) at util/qemu-thread-posix.c:519 #13 0x00007ff73eedf2de in start_thread () at /lib64/libpthread.so.0 #14 0x00007ff73ec10e83 in clone () at /lib64/libc.so.6 Thread 1 (Thread 0x7ff743986f00 (LWP 1062500)): #0 0x00005567a13b99d6 in iov_memset (iov=0x6563617073206f4e, iov_cnt=1717922848, offset=516096, fillc=0, bytes=7018105756081554803) at util/iov.c:69 #1 0x00005567a13bab73 in qemu_iovec_memset (qiov=0x7ff73ec99748, offset=516096, fillc=0, bytes=7018105756081554803) at util/iov.c:530 #2 0x00005567a12f411c in qemu_laio_process_completion (laiocb=0x7ff6512ee6c0) at block/linux-aio.c:86 #3 0x00005567a12f42ff in qemu_laio_process_completions (s=0x7ff7182e8420) at block/linux-aio.c:217 #4 0x00005567a12f480d in ioq_submit (s=0x7ff7182e8420) at block/linux-aio.c:323 #5 0x00005567a12f4a2f in laio_do_submit (fd=19, laiocb=0x7ff5f4ff9ae0, offset=472363008, type=2) at block/linux-aio.c:375 #6 0x00005567a12f4af2 in laio_co_submit (bs=0x5567a2b8c460, s=0x7ff7182e8420, fd=19, offset=472363008, qiov=0x7ff5f4ff9ca0, type=2) at block/linux-aio.c:394 #7 0x00005567a12f1803 in raw_co_prw (bs=0x5567a2b8c460, offset=472363008, bytes=20480, qiov=0x7ff5f4ff9ca0, type=2) at block/file-posix.c:1892 #8 0x00005567a12f1941 in raw_co_pwritev (bs=0x5567a2b8c460, offset=472363008, bytes=20480, qiov=0x7ff5f4ff9ca0, flags=0) at block/file-posix.c:1925 #9 0x00005567a12fe3e1 in bdrv_driver_pwritev (bs=0x5567a2b8c460, offset=472363008, bytes=20480, qiov=0x7ff5f4ff9ca0, qiov_offset=0, flags=0) at block/io.c:1183 #10 0x00005567a1300340 in bdrv_aligned_pwritev (child=0x5567a2b5b070, req=0x7ff5f4ff9db0, offset=472363008, bytes=20480, align=512, qiov=0x7ff72c0425b8, qiov_offset=0, flags=0) at block/io.c:1980 #11 0x00005567a1300b29 in bdrv_co_pwritev_part (child=0x5567a2b5b070, offset=472363008, bytes=20480, qiov=0x7ff72c0425b8, qiov_offset=0, flags=0) at block/io.c:2137 #12 0x00005567a12baba1 in qcow2_co_pwritev_task (bs=0x5567a2b92740, file_cluster_offset=472317952, offset=487305216, bytes=20480, qiov=0x7ff72c0425b8, qiov_offset=0, l2meta=0x0) at block/qcow2.c:2444 #13 0x00005567a12bacdb in qcow2_co_pwritev_task_entry (task=0x5567a2b48540) at block/qcow2.c:2475 #14 0x00005567a13167d8 in aio_task_co (opaque=0x5567a2b48540) at block/aio_task.c:45 #15 0x00005567a13cf00c in coroutine_trampoline (i0=738245600, i1=32759) at util/coroutine-ucontext.c:115 #16 0x00007ff73eb622e0 in __start_context () at /lib64/libc.so.6 #17 0x00007ff6626f1350 in () #18 0x0000000000000000 in () <------> This is also known to cause crashes with this message (assertion failed): aio_co_schedule: Co-routine was already scheduled in 'aio_co_schedule' RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1812765 Signed-off-by: Sergio Lopez <slp@redhat.com> Message-Id: <20200603093240.40489-3-slp@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-04-07xen-block: Fix double qlist remove and request leakAnthony PERARD
Commit a31ca6801c02 ("qemu/queue.h: clear linked list pointers on remove") revealed that a request was removed twice from a list, once in xen_block_finish_request() and a second time in xen_block_release_request() when both function are called from xen_block_complete_aio(). But also, the `requests_inflight' counter is decreased twice, and thus became negative. This is a bug that was introduced in bfd0d6366043 ("xen-block: improve response latency"), where a `finished' list was removed. That commit also introduced a leak of request in xen_block_do_aio(). That function calls xen_block_finish_request() but the request is never released after that. To fix both issue, we do two changes: - we squash finish_request() and release_request() together as we want to remove a request from 'inflight' list to add it to 'freelist'. - before releasing a request, we need to let the other end know the result, thus we should call xen_block_send_response() before releasing a request. The first change fixes the double QLIST_REMOVE() as we remove the extra call. The second change makes the leak go away because if we want to call finish_request(), we need to call a function that does all of finish, send response, and release. Fixes: bfd0d6366043 ("xen-block: improve response latency") Signed-off-by: Anthony PERARD <anthony.perard@citrix.com> Message-Id: <20200406140217.1441858-1-anthony.perard@citrix.com> Reviewed-by: Paul Durrant <paul@xen.org> [mreitz: Amended commit message as per Paul's suggestions] Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-02-27xen-bus/block: explicitly assign event channels to an AioContextPaul Durrant
It is not safe to close an event channel from the QEMU main thread when that channel's poller is running in IOThread context. This patch adds a new xen_device_set_event_channel_context() function to explicitly assign the channel AioContext, and modifies xen_device_bind_event_channel() to initially assign the channel's poller to the QEMU main thread context. The code in xen-block's dataplane is then modified to assign the channel to IOThread context during xen_block_dataplane_start() and de-assign it during in xen_block_dataplane_stop(), such that the channel is always assigned back to main thread context before it is closed. aio_set_fd_handler() already deals with all the necessary synchronization when moving an fd between AioContext-s so no extra code is needed to manage this. Reported-by: Julien Grall <jgrall@amazon.com> Signed-off-by: Paul Durrant <pdurrant@amazon.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Message-Id: <20191216143451.19024-1-pdurrant@amazon.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2019-12-19virtio-blk: fix out-of-bounds access to bitmap in notify_guest_bhLi Hangjing
When the number of a virtio-blk device's virtqueues is larger than BITS_PER_LONG, the out-of-bounds access to bitmap[ ] will occur. Fixes: e21737ab15 ("virtio-blk: multiqueue batch notify") Cc: qemu-stable@nongnu.org Cc: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Li Hangjing <lihangjing@baidu.com> Reviewed-by: Xie Yongji <xieyongji@baidu.com> Reviewed-by: Chai Wen <chaiwen@baidu.com> Message-id: 20191216023050.48620-1-lihangjing@baidu.com Message-Id: <20191216023050.48620-1-lihangjing@baidu.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2019-09-03virtio-blk: Cancel the pending BH when the dataplane is resetPhilippe Mathieu-Daudé
When 'system_reset' is called, the main loop clear the memory region cache before the BH has a chance to execute. Later when the deferred function is called, some assumptions that were made when scheduling them are no longer true when they actually execute. This is what happens using a virtio-blk device (fresh RHEL7.8 install): $ (sleep 12.3; echo system_reset; sleep 12.3; echo system_reset; sleep 1; echo q) \ | qemu-system-x86_64 -m 4G -smp 8 -boot menu=on \ -device virtio-blk-pci,id=image1,drive=drive_image1 \ -drive file=/var/lib/libvirt/images/rhel78.qcow2,if=none,id=drive_image1,format=qcow2,cache=none \ -device virtio-net-pci,netdev=net0,id=nic0,mac=52:54:00:c4:e7:84 \ -netdev tap,id=net0,script=/bin/true,downscript=/bin/true,vhost=on \ -monitor stdio -serial null -nographic (qemu) system_reset (qemu) system_reset (qemu) qemu-system-x86_64: hw/virtio/virtio.c:225: vring_get_region_caches: Assertion `caches != NULL' failed. Aborted (gdb) bt Thread 1 (Thread 0x7f109c17b680 (LWP 10939)): #0 0x00005604083296d1 in vring_get_region_caches (vq=0x56040a24bdd0) at hw/virtio/virtio.c:227 #1 0x000056040832972b in vring_avail_flags (vq=0x56040a24bdd0) at hw/virtio/virtio.c:235 #2 0x000056040832d13d in virtio_should_notify (vdev=0x56040a240630, vq=0x56040a24bdd0) at hw/virtio/virtio.c:1648 #3 0x000056040832d1f8 in virtio_notify_irqfd (vdev=0x56040a240630, vq=0x56040a24bdd0) at hw/virtio/virtio.c:1662 #4 0x00005604082d213d in notify_guest_bh (opaque=0x56040a243ec0) at hw/block/dataplane/virtio-blk.c:75 #5 0x000056040883dc35 in aio_bh_call (bh=0x56040a243f10) at util/async.c:90 #6 0x000056040883dccd in aio_bh_poll (ctx=0x560409161980) at util/async.c:118 #7 0x0000560408842af7 in aio_dispatch (ctx=0x560409161980) at util/aio-posix.c:460 #8 0x000056040883e068 in aio_ctx_dispatch (source=0x560409161980, callback=0x0, user_data=0x0) at util/async.c:261 #9 0x00007f10a8fca06d in g_main_context_dispatch () at /lib64/libglib-2.0.so.0 #10 0x0000560408841445 in glib_pollfds_poll () at util/main-loop.c:215 #11 0x00005604088414bf in os_host_main_loop_wait (timeout=0) at util/main-loop.c:238 #12 0x00005604088415c4 in main_loop_wait (nonblocking=0) at util/main-loop.c:514 #13 0x0000560408416b1e in main_loop () at vl.c:1923 #14 0x000056040841e0e8 in main (argc=20, argv=0x7ffc2c3f9c58, envp=0x7ffc2c3f9d00) at vl.c:4578 Fix this by cancelling the BH when the virtio dataplane is stopped. [This is version of the patch was modified as discussed with Philippe on the mailing list thread. --Stefan] Reported-by: Yihuang Yu <yihyu@redhat.com> Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> Fixes: https://bugs.launchpad.net/qemu/+bug/1839428 Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20190816171503.24761-1-philmd@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2019-08-16Include qemu/main-loop.h lessMarkus Armbruster
In my "build everything" tree, changing qemu/main-loop.h triggers a recompile of some 5600 out of 6600 objects (not counting tests and objects that don't depend on qemu/osdep.h). It includes block/aio.h, which in turn includes qemu/event_notifier.h, qemu/notify.h, qemu/processor.h, qemu/qsp.h, qemu/queue.h, qemu/thread-posix.h, qemu/thread.h, qemu/timer.h, and a few more. Include qemu/main-loop.h only where it's needed. Touching it now recompiles only some 1700 objects. For block/aio.h and qemu/event_notifier.h, these numbers drop from 5600 to 2800. For the others, they shrink only slightly. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190812052359.30071-21-armbru@redhat.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2019-08-16Include hw/hw.h exactly where neededMarkus Armbruster
In my "build everything" tree, changing hw/hw.h triggers a recompile of some 2600 out of 6600 objects (not counting tests and objects that don't depend on qemu/osdep.h). The previous commits have left only the declaration of hw_error() in hw/hw.h. This permits dropping most of its inclusions. Touching it now recompiles less than 200 objects. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20190812052359.30071-19-armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2019-06-24xen-bus / xen-block: add support for event channel pollingPaul Durrant
This patch introduces a poll callback for event channel fd-s and uses this to invoke the channel callback function. To properly support polling, it is necessary for the event channel callback function to return a boolean saying whether it has done any useful work or not. Thus xen_block_dataplane_event() is modified to directly invoke xen_block_handle_requests() and the latter only returns true if it actually processes any requests. This also means that the call to qemu_bh_schedule() is moved into xen_block_complete_aio(), which is more intuitive since the only reason for doing a deferred poll of the shared ring should be because there were previously insufficient resources to fully complete a previous poll. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Message-Id: <20190408151617.13025-4-paul.durrant@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2019-06-24xen-bus: allow AioContext to be specified for each event channelPaul Durrant
This patch adds an AioContext parameter to xen_device_bind_event_channel() and then uses aio_set_fd_handler() to set the callback rather than qemu_set_fd_handler(). Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Message-Id: <20190408151617.13025-3-paul.durrant@citrix.com> [Call aio_set_fd_handler() with is_external=true] Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2019-06-24xen-block: support feature-large-sector-sizePaul Durrant
A recent Xen commit [1] clarified the semantics of sector based quantities used in the blkif protocol such that it is now safe to create a xen-block device with a logical_block_size != 512, as long as the device only connects to a frontend advertizing 'feature-large-block-size'. This patch modifies xen-block accordingly. It also uses a stack variable for the BlockBackend in xen_block_realize() to avoid repeated dereferencing of the BlockConf pointer, and changes the parameters of xen_block_dataplane_create() so that the BlockBackend pointer and sector size are passed expicitly rather than implicitly via the BlockConf. These modifications have been tested against a recent Windows PV XENVBD driver [2] using a xen-disk device with a 4kB logical block size. [1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=67e1c050e36b2c9900cca83618e56189effbad98 [2] https://winpvdrvbuild.xenproject.org:8080/job/XENVBD-master/126 Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Message-Id: <20190409164038.25484-1-paul.durrant@citrix.com> [Edited error message] Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2019-06-04block: Add Error to blk_set_aio_context()Kevin Wolf
Add an Error parameter to blk_set_aio_context() and use bdrv_child_try_set_aio_context() internally to check whether all involved nodes can actually support the AioContext switch. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-04-04xen-block: scale sector based quantities correctlyPaul Durrant
The Xen blkif protocol requires that sector based quantities should be interpreted strictly as multiples of 512 bytes. Specifically: "first_sect and last_sect in blkif_request_segment, as well as sector_number in blkif_request, are always expressed in 512-byte units." Commit fcab2b464e06 "xen: add header and build dataplane/xen-block.c" incorrectly modified behaviour to use the block device logical_block_size property as the scale, instead of correctly shifting values by the hardcoded BDRV_SECTOR_BITS (and hence scaling them to 512 byte units). This patch undoes that change and restores compliance with the spec. Furthermore, this patch also restores the original xen_disk behaviour of advertizing a hardcoded 'sector-size' value of 512 in xenstore and scaling 'sectors' accordingly. The realize() method is also modified to fail if logical_block_size is set to anything other than 512. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Reviewed-by: Anthony PERARD <anthony.perard@citrix.com> Message-Id: <20190401121719.27208-1-paul.durrant@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2019-03-22trace-events: Shorten file names in commentsMarkus Armbruster
We spell out sub/dir/ in sub/dir/trace-events' comments pointing to source files. That's because when trace-events got split up, the comments were moved verbatim. Delete the sub/dir/ part from these comments. Gets rid of several misspellings. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-id: 20190314180929.27722-3-armbru@redhat.com Message-Id: <20190314180929.27722-3-armbru@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2019-03-07block: fix recursion in hw/block/dataplanePaolo Bonzini
There are Xen files in hw/block/dataplane that should be compiled even if virtio-blk is disabled. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>