From patchwork Fri Jan 19 13:57:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13523813 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DB501C47DAF for ; Fri, 19 Jan 2024 14:00:06 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rQpOG-0004iP-HV; Fri, 19 Jan 2024 08:58:36 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rQpOA-0004Ut-9d for qemu-devel@nongnu.org; Fri, 19 Jan 2024 08:58:31 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rQpO4-0000Xv-4y for qemu-devel@nongnu.org; Fri, 19 Jan 2024 08:58:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1705672701; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MgNpJc0g0yj5VXGCE2vGalY76qAKYcJc8cNoJdaRIMI=; b=BvhWBg7OmHJ/++zT83VCGc+t6dfIXeUL4fzhN/67qhu2nIM+AXCBtjA+U8oUsWA7N8n75H iOuC+hAX05Lp4e4V1c9EK5Wb2vqTqe/P7ttc9Gev4+KKjUUORxpsC26uhU+OKrvQ045gtp n5rkXDvg0LvxfOOJv1QRSsJk5yAwE/8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-656-tesN68xvNeeixcDioJXwrw-1; Fri, 19 Jan 2024 08:58:14 -0500 X-MC-Unique: tesN68xvNeeixcDioJXwrw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 30C63185A780; Fri, 19 Jan 2024 13:58:14 +0000 (UTC) Received: from localhost (unknown [10.39.195.31]) by smtp.corp.redhat.com (Postfix) with ESMTP id B16572166B35; Fri, 19 Jan 2024 13:58:12 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Stefan Hajnoczi , Thomas Huth , Hanna Reitz , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , qemu-block@nongnu.org, "Michael S. Tsirkin" , Kevin Wolf , Paolo Bonzini , =?utf-8?q?Marc-Andr=C3=A9_Lureau?= , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= Subject: [PATCH 1/6] virtio-blk: move dataplane code into virtio-blk.c Date: Fri, 19 Jan 2024 08:57:43 -0500 Message-ID: <20240119135748.270944-2-stefanha@redhat.com> In-Reply-To: <20240119135748.270944-1-stefanha@redhat.com> References: <20240119135748.270944-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -45 X-Spam_score: -4.6 X-Spam_bar: ---- X-Spam_report: (-4.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.519, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org 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 --- meson.build | 1 - hw/block/dataplane/trace.h | 1 - hw/block/dataplane/virtio-blk.h | 34 --- include/hw/virtio/virtio-blk.h | 12 +- hw/block/dataplane/virtio-blk.c | 404 -------------------------------- hw/block/virtio-blk.c | 362 ++++++++++++++++++++++++++-- hw/block/dataplane/meson.build | 1 - hw/block/dataplane/trace-events | 5 - 8 files changed, 357 insertions(+), 463 deletions(-) delete mode 100644 hw/block/dataplane/trace.h delete mode 100644 hw/block/dataplane/virtio-blk.h delete mode 100644 hw/block/dataplane/virtio-blk.c delete mode 100644 hw/block/dataplane/trace-events diff --git a/meson.build b/meson.build index 38deb9363c..38745771f9 100644 --- a/meson.build +++ b/meson.build @@ -3270,7 +3270,6 @@ if have_system 'hw/arm', 'hw/audio', 'hw/block', - 'hw/block/dataplane', 'hw/char', 'hw/display', 'hw/dma', diff --git a/hw/block/dataplane/trace.h b/hw/block/dataplane/trace.h deleted file mode 100644 index 240cc59834..0000000000 --- a/hw/block/dataplane/trace.h +++ /dev/null @@ -1 +0,0 @@ -#include "trace/trace-hw_block_dataplane.h" diff --git a/hw/block/dataplane/virtio-blk.h b/hw/block/dataplane/virtio-blk.h deleted file mode 100644 index 1a806fe447..0000000000 --- a/hw/block/dataplane/virtio-blk.h +++ /dev/null @@ -1,34 +0,0 @@ -/* - * Dedicated thread for virtio-blk I/O processing - * - * Copyright 2012 IBM, Corp. - * Copyright 2012 Red Hat, Inc. and/or its affiliates - * - * Authors: - * Stefan Hajnoczi - * - * This work is licensed under the terms of the GNU GPL, version 2 or later. - * See the COPYING file in the top-level directory. - * - */ - -#ifndef HW_DATAPLANE_VIRTIO_BLK_H -#define HW_DATAPLANE_VIRTIO_BLK_H - -#include "hw/virtio/virtio.h" - -typedef struct VirtIOBlockDataPlane VirtIOBlockDataPlane; - -bool virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf, - VirtIOBlockDataPlane **dataplane, - Error **errp); -void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s); -void virtio_blk_data_plane_notify(VirtIOBlockDataPlane *s, VirtQueue *vq); - -int virtio_blk_data_plane_start(VirtIODevice *vdev); -void virtio_blk_data_plane_stop(VirtIODevice *vdev); - -void virtio_blk_data_plane_detach(VirtIOBlockDataPlane *s); -void virtio_blk_data_plane_attach(VirtIOBlockDataPlane *s); - -#endif /* HW_DATAPLANE_VIRTIO_BLK_H */ diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index 5e4091e4da..fecffdc303 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -50,8 +50,6 @@ struct VirtIOBlkConf bool x_enable_wce_if_config_wce; }; -struct VirtIOBlockDataPlane; - struct VirtIOBlockReq; struct VirtIOBlock { VirtIODevice parent_obj; @@ -64,7 +62,15 @@ struct VirtIOBlock { VMChangeStateEntry *change; bool dataplane_disabled; bool dataplane_started; - struct VirtIOBlockDataPlane *dataplane; + bool dataplane_starting; + bool dataplane_stopping; + + /* + * The AioContext for each virtqueue. The BlockDriverState will use the + * first element as its AioContext. + */ + AioContext **vq_aio_context; + uint64_t host_features; size_t config_size; BlockRAMRegistrar blk_ram_registrar; diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c deleted file mode 100644 index ba22732497..0000000000 --- a/hw/block/dataplane/virtio-blk.c +++ /dev/null @@ -1,404 +0,0 @@ -/* - * Dedicated thread for virtio-blk I/O processing - * - * Copyright 2012 IBM, Corp. - * Copyright 2012 Red Hat, Inc. and/or its affiliates - * - * Authors: - * Stefan Hajnoczi - * - * This work is licensed under the terms of the GNU GPL, version 2 or later. - * See the COPYING file in the top-level directory. - * - */ - -#include "qemu/osdep.h" -#include "qapi/error.h" -#include "trace.h" -#include "qemu/iov.h" -#include "qemu/main-loop.h" -#include "qemu/thread.h" -#include "qemu/error-report.h" -#include "hw/virtio/virtio-blk.h" -#include "virtio-blk.h" -#include "block/aio.h" -#include "hw/virtio/virtio-bus.h" -#include "qom/object_interfaces.h" - -struct VirtIOBlockDataPlane { - bool starting; - bool stopping; - - VirtIOBlkConf *conf; - VirtIODevice *vdev; - - /* - * The AioContext for each virtqueue. The BlockDriverState will use the - * first element as its AioContext. - */ - AioContext **vq_aio_context; -}; - -/* Raise an interrupt to signal guest, if necessary */ -void virtio_blk_data_plane_notify(VirtIOBlockDataPlane *s, VirtQueue *vq) -{ - virtio_notify_irqfd(s->vdev, vq); -} - -/* Generate vq:AioContext mappings from a validated iothread-vq-mapping list */ -static void -apply_vq_mapping(IOThreadVirtQueueMappingList *iothread_vq_mapping_list, - AioContext **vq_aio_context, uint16_t num_queues) -{ - IOThreadVirtQueueMappingList *node; - size_t num_iothreads = 0; - size_t cur_iothread = 0; - - for (node = iothread_vq_mapping_list; node; node = node->next) { - num_iothreads++; - } - - for (node = iothread_vq_mapping_list; node; node = node->next) { - IOThread *iothread = iothread_by_id(node->value->iothread); - AioContext *ctx = iothread_get_aio_context(iothread); - - /* Released in virtio_blk_data_plane_destroy() */ - object_ref(OBJECT(iothread)); - - if (node->value->vqs) { - uint16List *vq; - - /* Explicit vq:IOThread assignment */ - for (vq = node->value->vqs; vq; vq = vq->next) { - vq_aio_context[vq->value] = ctx; - } - } else { - /* Round-robin vq:IOThread assignment */ - for (unsigned i = cur_iothread; i < num_queues; - i += num_iothreads) { - vq_aio_context[i] = ctx; - } - } - - cur_iothread++; - } -} - -/* Context: BQL held */ -bool virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *conf, - VirtIOBlockDataPlane **dataplane, - Error **errp) -{ - VirtIOBlockDataPlane *s; - BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); - VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); - - *dataplane = NULL; - - if (conf->iothread || conf->iothread_vq_mapping_list) { - if (!k->set_guest_notifiers || !k->ioeventfd_assign) { - error_setg(errp, - "device is incompatible with iothread " - "(transport does not support notifiers)"); - return false; - } - if (!virtio_device_ioeventfd_enabled(vdev)) { - error_setg(errp, "ioeventfd is required for iothread"); - return false; - } - - /* If dataplane is (re-)enabled while the guest is running there could - * be block jobs that can conflict. - */ - if (blk_op_is_blocked(conf->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) { - error_prepend(errp, "cannot start virtio-blk dataplane: "); - return false; - } - } - /* Don't try if transport does not support notifiers. */ - if (!virtio_device_ioeventfd_enabled(vdev)) { - return false; - } - - s = g_new0(VirtIOBlockDataPlane, 1); - s->vdev = vdev; - s->conf = conf; - s->vq_aio_context = g_new(AioContext *, conf->num_queues); - - if (conf->iothread_vq_mapping_list) { - apply_vq_mapping(conf->iothread_vq_mapping_list, s->vq_aio_context, - conf->num_queues); - } else if (conf->iothread) { - AioContext *ctx = iothread_get_aio_context(conf->iothread); - for (unsigned i = 0; i < conf->num_queues; i++) { - s->vq_aio_context[i] = ctx; - } - - /* Released in virtio_blk_data_plane_destroy() */ - object_ref(OBJECT(conf->iothread)); - } else { - AioContext *ctx = qemu_get_aio_context(); - for (unsigned i = 0; i < conf->num_queues; i++) { - s->vq_aio_context[i] = ctx; - } - } - - *dataplane = s; - - return true; -} - -/* Context: BQL held */ -void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s) -{ - VirtIOBlock *vblk; - VirtIOBlkConf *conf; - - if (!s) { - return; - } - - vblk = VIRTIO_BLK(s->vdev); - assert(!vblk->dataplane_started); - conf = s->conf; - - if (conf->iothread_vq_mapping_list) { - IOThreadVirtQueueMappingList *node; - - for (node = conf->iothread_vq_mapping_list; node; node = node->next) { - IOThread *iothread = iothread_by_id(node->value->iothread); - object_unref(OBJECT(iothread)); - } - } - - if (conf->iothread) { - object_unref(OBJECT(conf->iothread)); - } - - g_free(s->vq_aio_context); - g_free(s); -} - -/* Context: BQL held */ -int virtio_blk_data_plane_start(VirtIODevice *vdev) -{ - VirtIOBlock *vblk = VIRTIO_BLK(vdev); - VirtIOBlockDataPlane *s = vblk->dataplane; - BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vblk))); - VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); - unsigned i; - unsigned nvqs = s->conf->num_queues; - Error *local_err = NULL; - int r; - - if (vblk->dataplane_started || s->starting) { - return 0; - } - - s->starting = true; - - /* Set up guest notifier (irq) */ - r = k->set_guest_notifiers(qbus->parent, nvqs, true); - if (r != 0) { - error_report("virtio-blk failed to set guest notifier (%d), " - "ensure -accel kvm is set.", r); - goto fail_guest_notifiers; - } - - /* - * Batch all the host notifiers in a single transaction to avoid - * quadratic time complexity in address_space_update_ioeventfds(). - */ - memory_region_transaction_begin(); - - /* Set up virtqueue notify */ - for (i = 0; i < nvqs; i++) { - r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, true); - if (r != 0) { - int j = i; - - fprintf(stderr, "virtio-blk failed to set host notifier (%d)\n", r); - while (i--) { - virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); - } - - /* - * The transaction expects the ioeventfds to be open when it - * commits. Do it now, before the cleanup loop. - */ - memory_region_transaction_commit(); - - while (j--) { - virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), j); - } - goto fail_host_notifiers; - } - } - - memory_region_transaction_commit(); - - trace_virtio_blk_data_plane_start(s); - - r = blk_set_aio_context(s->conf->conf.blk, s->vq_aio_context[0], - &local_err); - if (r < 0) { - error_report_err(local_err); - goto fail_aio_context; - } - - /* - * These fields must be visible to the IOThread when it processes the - * virtqueue, otherwise it will think dataplane has not started yet. - * - * Make sure ->dataplane_started is false when blk_set_aio_context() is - * called above so that draining does not cause the host notifier to be - * detached/attached prematurely. - */ - s->starting = false; - vblk->dataplane_started = true; - smp_wmb(); /* paired with aio_notify_accept() on the read side */ - - /* Get this show started by hooking up our callbacks */ - if (!blk_in_drain(s->conf->conf.blk)) { - for (i = 0; i < nvqs; i++) { - VirtQueue *vq = virtio_get_queue(s->vdev, i); - AioContext *ctx = s->vq_aio_context[i]; - - /* Kick right away to begin processing requests already in vring */ - event_notifier_set(virtio_queue_get_host_notifier(vq)); - - virtio_queue_aio_attach_host_notifier(vq, ctx); - } - } - return 0; - - fail_aio_context: - memory_region_transaction_begin(); - - for (i = 0; i < nvqs; i++) { - virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); - } - - memory_region_transaction_commit(); - - for (i = 0; i < nvqs; i++) { - virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i); - } - fail_host_notifiers: - k->set_guest_notifiers(qbus->parent, nvqs, false); - fail_guest_notifiers: - vblk->dataplane_disabled = true; - s->starting = false; - return -ENOSYS; -} - -/* Stop notifications for new requests from guest. - * - * Context: BH in IOThread - */ -static void virtio_blk_data_plane_stop_vq_bh(void *opaque) -{ - VirtQueue *vq = opaque; - EventNotifier *host_notifier = virtio_queue_get_host_notifier(vq); - - virtio_queue_aio_detach_host_notifier(vq, qemu_get_current_aio_context()); - - /* - * Test and clear notifier after disabling event, in case poll callback - * didn't have time to run. - */ - virtio_queue_host_notifier_read(host_notifier); -} - -/* Context: BQL held */ -void virtio_blk_data_plane_stop(VirtIODevice *vdev) -{ - VirtIOBlock *vblk = VIRTIO_BLK(vdev); - VirtIOBlockDataPlane *s = vblk->dataplane; - BusState *qbus = qdev_get_parent_bus(DEVICE(vblk)); - VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); - unsigned i; - unsigned nvqs = s->conf->num_queues; - - if (!vblk->dataplane_started || s->stopping) { - return; - } - - /* Better luck next time. */ - if (vblk->dataplane_disabled) { - vblk->dataplane_disabled = false; - vblk->dataplane_started = false; - return; - } - s->stopping = true; - trace_virtio_blk_data_plane_stop(s); - - if (!blk_in_drain(s->conf->conf.blk)) { - for (i = 0; i < nvqs; i++) { - VirtQueue *vq = virtio_get_queue(s->vdev, i); - AioContext *ctx = s->vq_aio_context[i]; - - aio_wait_bh_oneshot(ctx, virtio_blk_data_plane_stop_vq_bh, vq); - } - } - - /* - * Batch all the host notifiers in a single transaction to avoid - * quadratic time complexity in address_space_update_ioeventfds(). - */ - memory_region_transaction_begin(); - - for (i = 0; i < nvqs; i++) { - virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); - } - - /* - * The transaction expects the ioeventfds to be open when it - * commits. Do it now, before the cleanup loop. - */ - memory_region_transaction_commit(); - - for (i = 0; i < nvqs; i++) { - virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i); - } - - /* - * Set ->dataplane_started to false before draining so that host notifiers - * are not detached/attached anymore. - */ - vblk->dataplane_started = false; - - /* Wait for virtio_blk_dma_restart_bh() and in flight I/O to complete */ - blk_drain(s->conf->conf.blk); - - /* - * Try to switch bs back to the QEMU main loop. If other users keep the - * BlockBackend in the iothread, that's ok - */ - blk_set_aio_context(s->conf->conf.blk, qemu_get_aio_context(), NULL); - - /* Clean up guest notifier (irq) */ - k->set_guest_notifiers(qbus->parent, nvqs, false); - - s->stopping = false; -} - -void virtio_blk_data_plane_detach(VirtIOBlockDataPlane *s) -{ - VirtIODevice *vdev = VIRTIO_DEVICE(s->vdev); - - for (uint16_t i = 0; i < s->conf->num_queues; i++) { - VirtQueue *vq = virtio_get_queue(vdev, i); - virtio_queue_aio_detach_host_notifier(vq, s->vq_aio_context[i]); - } -} - -void virtio_blk_data_plane_attach(VirtIOBlockDataPlane *s) -{ - VirtIODevice *vdev = VIRTIO_DEVICE(s->vdev); - - for (uint16_t i = 0; i < s->conf->num_queues; i++) { - VirtQueue *vq = virtio_get_queue(vdev, i); - virtio_queue_aio_attach_host_notifier(vq, s->vq_aio_context[i]); - } -} diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index b7a344ca97..510cb4248d 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -27,7 +27,6 @@ #include "sysemu/sysemu.h" #include "sysemu/runstate.h" #include "hw/virtio/virtio-blk.h" -#include "dataplane/virtio-blk.h" #include "scsi/constants.h" #ifdef __linux__ # include @@ -66,7 +65,7 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status) iov_discard_undo(&req->outhdr_undo); virtqueue_push(req->vq, &req->elem, req->in_len); if (s->dataplane_started && !s->dataplane_disabled) { - virtio_blk_data_plane_notify(s->dataplane, req->vq); + virtio_notify_irqfd(vdev, req->vq); } else { virtio_notify(vdev, req->vq); } @@ -1142,7 +1141,7 @@ static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) { VirtIOBlock *s = (VirtIOBlock *)vdev; - if (s->dataplane && !s->dataplane_started) { + if (!s->dataplane_disabled && !s->dataplane_started) { /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start * dataplane here instead of waiting for .set_status(). */ @@ -1546,16 +1545,34 @@ static void virtio_blk_resize(void *opaque) aio_bh_schedule_oneshot(qemu_get_aio_context(), virtio_resize_cb, vdev); } +static void virtio_blk_data_plane_detach(VirtIOBlock *s) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + for (uint16_t i = 0; i < s->conf.num_queues; i++) { + VirtQueue *vq = virtio_get_queue(vdev, i); + virtio_queue_aio_detach_host_notifier(vq, s->vq_aio_context[i]); + } +} + +static void virtio_blk_data_plane_attach(VirtIOBlock *s) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(s); + + for (uint16_t i = 0; i < s->conf.num_queues; i++) { + VirtQueue *vq = virtio_get_queue(vdev, i); + virtio_queue_aio_attach_host_notifier(vq, s->vq_aio_context[i]); + } +} + /* Suspend virtqueue ioeventfd processing during drain */ static void virtio_blk_drained_begin(void *opaque) { VirtIOBlock *s = opaque; - if (!s->dataplane || !s->dataplane_started) { - return; + if (s->dataplane_started) { + virtio_blk_data_plane_detach(s); } - - virtio_blk_data_plane_detach(s->dataplane); } /* Resume virtqueue ioeventfd processing after drain */ @@ -1563,11 +1580,9 @@ static void virtio_blk_drained_end(void *opaque) { VirtIOBlock *s = opaque; - if (!s->dataplane || !s->dataplane_started) { - return; + if (s->dataplane_started) { + virtio_blk_data_plane_attach(s); } - - virtio_blk_data_plane_attach(s->dataplane); } static const BlockDevOps virtio_block_ops = { @@ -1576,6 +1591,326 @@ static const BlockDevOps virtio_block_ops = { .drained_end = virtio_blk_drained_end, }; +/* Generate vq:AioContext mappings from a validated iothread-vq-mapping list */ +static void +apply_vq_mapping(IOThreadVirtQueueMappingList *iothread_vq_mapping_list, + AioContext **vq_aio_context, uint16_t num_queues) +{ + IOThreadVirtQueueMappingList *node; + size_t num_iothreads = 0; + size_t cur_iothread = 0; + + for (node = iothread_vq_mapping_list; node; node = node->next) { + num_iothreads++; + } + + for (node = iothread_vq_mapping_list; node; node = node->next) { + IOThread *iothread = iothread_by_id(node->value->iothread); + AioContext *ctx = iothread_get_aio_context(iothread); + + /* Released in virtio_blk_data_plane_destroy() */ + object_ref(OBJECT(iothread)); + + if (node->value->vqs) { + uint16List *vq; + + /* Explicit vq:IOThread assignment */ + for (vq = node->value->vqs; vq; vq = vq->next) { + vq_aio_context[vq->value] = ctx; + } + } else { + /* Round-robin vq:IOThread assignment */ + for (unsigned i = cur_iothread; i < num_queues; + i += num_iothreads) { + vq_aio_context[i] = ctx; + } + } + + cur_iothread++; + } +} + +/* Context: BQL held */ +static bool virtio_blk_data_plane_create(VirtIOBlock *s, Error **errp) +{ + VirtIODevice *vdev = VIRTIO_DEVICE(s); + VirtIOBlkConf *conf = &s->conf; + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + + if (conf->iothread || conf->iothread_vq_mapping_list) { + if (!k->set_guest_notifiers || !k->ioeventfd_assign) { + error_setg(errp, + "device is incompatible with iothread " + "(transport does not support notifiers)"); + return false; + } + if (!virtio_device_ioeventfd_enabled(vdev)) { + error_setg(errp, "ioeventfd is required for iothread"); + return false; + } + + /* + * If dataplane is (re-)enabled while the guest is running there could + * be block jobs that can conflict. + */ + if (blk_op_is_blocked(conf->conf.blk, BLOCK_OP_TYPE_DATAPLANE, errp)) { + error_prepend(errp, "cannot start virtio-blk dataplane: "); + return false; + } + } + /* Don't try if transport does not support notifiers. */ + if (!virtio_device_ioeventfd_enabled(vdev)) { + s->dataplane_disabled = true; + return false; + } + + s->vq_aio_context = g_new(AioContext *, conf->num_queues); + + if (conf->iothread_vq_mapping_list) { + apply_vq_mapping(conf->iothread_vq_mapping_list, s->vq_aio_context, + conf->num_queues); + } else if (conf->iothread) { + AioContext *ctx = iothread_get_aio_context(conf->iothread); + for (unsigned i = 0; i < conf->num_queues; i++) { + s->vq_aio_context[i] = ctx; + } + + /* Released in virtio_blk_data_plane_destroy() */ + object_ref(OBJECT(conf->iothread)); + } else { + AioContext *ctx = qemu_get_aio_context(); + for (unsigned i = 0; i < conf->num_queues; i++) { + s->vq_aio_context[i] = ctx; + } + } + + return true; +} + +/* Context: BQL held */ +static void virtio_blk_data_plane_destroy(VirtIOBlock *s) +{ + VirtIOBlkConf *conf = &s->conf; + + assert(!s->dataplane_started); + + if (conf->iothread_vq_mapping_list) { + IOThreadVirtQueueMappingList *node; + + for (node = conf->iothread_vq_mapping_list; node; node = node->next) { + IOThread *iothread = iothread_by_id(node->value->iothread); + object_unref(OBJECT(iothread)); + } + } + + if (conf->iothread) { + object_unref(OBJECT(conf->iothread)); + } + + g_free(s->vq_aio_context); + s->vq_aio_context = NULL; +} + +/* Context: BQL held */ +static int virtio_blk_data_plane_start(VirtIODevice *vdev) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s))); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + unsigned i; + unsigned nvqs = s->conf.num_queues; + Error *local_err = NULL; + int r; + + if (s->dataplane_started || s->dataplane_starting) { + return 0; + } + + s->dataplane_starting = true; + + /* Set up guest notifier (irq) */ + r = k->set_guest_notifiers(qbus->parent, nvqs, true); + if (r != 0) { + error_report("virtio-blk failed to set guest notifier (%d), " + "ensure -accel kvm is set.", r); + goto fail_guest_notifiers; + } + + /* + * Batch all the host notifiers in a single transaction to avoid + * quadratic time complexity in address_space_update_ioeventfds(). + */ + memory_region_transaction_begin(); + + /* Set up virtqueue notify */ + for (i = 0; i < nvqs; i++) { + r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, true); + if (r != 0) { + int j = i; + + fprintf(stderr, "virtio-blk failed to set host notifier (%d)\n", r); + while (i--) { + virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); + } + + /* + * The transaction expects the ioeventfds to be open when it + * commits. Do it now, before the cleanup loop. + */ + memory_region_transaction_commit(); + + while (j--) { + virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), j); + } + goto fail_host_notifiers; + } + } + + memory_region_transaction_commit(); + + r = blk_set_aio_context(s->conf.conf.blk, s->vq_aio_context[0], + &local_err); + if (r < 0) { + error_report_err(local_err); + goto fail_aio_context; + } + + /* + * These fields must be visible to the IOThread when it processes the + * virtqueue, otherwise it will think dataplane has not started yet. + * + * Make sure ->dataplane_started is false when blk_set_aio_context() is + * called above so that draining does not cause the host notifier to be + * detached/attached prematurely. + */ + s->dataplane_starting = false; + s->dataplane_started = true; + smp_wmb(); /* paired with aio_notify_accept() on the read side */ + + /* Get this show started by hooking up our callbacks */ + if (!blk_in_drain(s->conf.conf.blk)) { + for (i = 0; i < nvqs; i++) { + VirtQueue *vq = virtio_get_queue(vdev, i); + AioContext *ctx = s->vq_aio_context[i]; + + /* Kick right away to begin processing requests already in vring */ + event_notifier_set(virtio_queue_get_host_notifier(vq)); + + virtio_queue_aio_attach_host_notifier(vq, ctx); + } + } + return 0; + + fail_aio_context: + memory_region_transaction_begin(); + + for (i = 0; i < nvqs; i++) { + virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); + } + + memory_region_transaction_commit(); + + for (i = 0; i < nvqs; i++) { + virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i); + } + fail_host_notifiers: + k->set_guest_notifiers(qbus->parent, nvqs, false); + fail_guest_notifiers: + s->dataplane_disabled = true; + s->dataplane_starting = false; + return -ENOSYS; +} + +/* Stop notifications for new requests from guest. + * + * Context: BH in IOThread + */ +static void virtio_blk_data_plane_stop_vq_bh(void *opaque) +{ + VirtQueue *vq = opaque; + EventNotifier *host_notifier = virtio_queue_get_host_notifier(vq); + + virtio_queue_aio_detach_host_notifier(vq, qemu_get_current_aio_context()); + + /* + * Test and clear notifier after disabling event, in case poll callback + * didn't have time to run. + */ + virtio_queue_host_notifier_read(host_notifier); +} + +/* Context: BQL held */ +static void virtio_blk_data_plane_stop(VirtIODevice *vdev) +{ + VirtIOBlock *s = VIRTIO_BLK(vdev); + BusState *qbus = qdev_get_parent_bus(DEVICE(s)); + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); + unsigned i; + unsigned nvqs = s->conf.num_queues; + + if (!s->dataplane_started || s->dataplane_stopping) { + return; + } + + /* Better luck next time. */ + if (s->dataplane_disabled) { + s->dataplane_disabled = false; + s->dataplane_started = false; + return; + } + s->dataplane_stopping = true; + + if (!blk_in_drain(s->conf.conf.blk)) { + for (i = 0; i < nvqs; i++) { + VirtQueue *vq = virtio_get_queue(vdev, i); + AioContext *ctx = s->vq_aio_context[i]; + + aio_wait_bh_oneshot(ctx, virtio_blk_data_plane_stop_vq_bh, vq); + } + } + + /* + * Batch all the host notifiers in a single transaction to avoid + * quadratic time complexity in address_space_update_ioeventfds(). + */ + memory_region_transaction_begin(); + + for (i = 0; i < nvqs; i++) { + virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), i, false); + } + + /* + * The transaction expects the ioeventfds to be open when it + * commits. Do it now, before the cleanup loop. + */ + memory_region_transaction_commit(); + + for (i = 0; i < nvqs; i++) { + virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), i); + } + + /* + * Set ->dataplane_started to false before draining so that host notifiers + * are not detached/attached anymore. + */ + s->dataplane_started = false; + + /* Wait for virtio_blk_dma_restart_bh() and in flight I/O to complete */ + blk_drain(s->conf.conf.blk); + + /* + * Try to switch bs back to the QEMU main loop. If other users keep the + * BlockBackend in the iothread, that's ok + */ + blk_set_aio_context(s->conf.conf.blk, qemu_get_aio_context(), NULL); + + /* Clean up guest notifier (irq) */ + k->set_guest_notifiers(qbus->parent, nvqs, false); + + s->dataplane_stopping = false; +} + static void virtio_blk_device_realize(DeviceState *dev, Error **errp) { VirtIODevice *vdev = VIRTIO_DEVICE(dev); @@ -1680,7 +2015,7 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp) virtio_add_queue(vdev, conf->queue_size, virtio_blk_handle_output); } qemu_coroutine_inc_pool_size(conf->num_queues * conf->queue_size / 2); - virtio_blk_data_plane_create(vdev, conf, &s->dataplane, &err); + virtio_blk_data_plane_create(s, &err); if (err != NULL) { error_propagate(errp, err); for (i = 0; i < conf->num_queues; i++) { @@ -1717,8 +2052,7 @@ static void virtio_blk_device_unrealize(DeviceState *dev) blk_drain(s->blk); del_boot_device_lchs(dev, "/disk@0,0"); - virtio_blk_data_plane_destroy(s->dataplane); - s->dataplane = NULL; + virtio_blk_data_plane_destroy(s); for (i = 0; i < conf->num_queues; i++) { virtio_del_queue(vdev, i); } diff --git a/hw/block/dataplane/meson.build b/hw/block/dataplane/meson.build index 025b3b061b..11a5eba2f4 100644 --- a/hw/block/dataplane/meson.build +++ b/hw/block/dataplane/meson.build @@ -1,2 +1 @@ -system_ss.add(when: 'CONFIG_VIRTIO_BLK', if_true: files('virtio-blk.c')) specific_ss.add(when: 'CONFIG_XEN_BUS', if_true: files('xen-block.c')) diff --git a/hw/block/dataplane/trace-events b/hw/block/dataplane/trace-events deleted file mode 100644 index 38fc3e7507..0000000000 --- a/hw/block/dataplane/trace-events +++ /dev/null @@ -1,5 +0,0 @@ -# See docs/devel/tracing.rst for syntax documentation. - -# virtio-blk.c -virtio_blk_data_plane_start(void *s) "dataplane %p" -virtio_blk_data_plane_stop(void *s) "dataplane %p"