From mboxrd@z Thu Jan 1 00:00:00 1970 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 A0A74C3DA4A for ; Mon, 19 Aug 2024 15:51:48 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sg4ew-0003Li-7X; Mon, 19 Aug 2024 11:51:06 -0400 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 1sg4eu-0003KY-HF for qemu-devel@nongnu.org; Mon, 19 Aug 2024 11:51:04 -0400 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 1sg4em-0004xP-Vt for qemu-devel@nongnu.org; Mon, 19 Aug 2024 11:51:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1724082655; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pVlbQyzSrmr80QP6wCh9uo/OrSot8fgSEiVruMsUdCI=; b=KedhwtG3p8/XO44Z2GN6ApsB9u4ZXAVgHIFcM4nhtoXQr88r12Ed8oIW5Q1uLnrsw7psoo 7uUz9vTRsfkW05cgce4wRKoyx0N1XUuMpiCHCnrmYU3bONxWibjS9/ilG+VpQyM2sijwPb iaVgsIaaq2pODmhZEDEqf4IP2pvbqgU= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-176-2w119aSBNS66hTPxj6qXXA-1; Mon, 19 Aug 2024 11:50:53 -0400 X-MC-Unique: 2w119aSBNS66hTPxj6qXXA-1 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-4281310bf7aso35995525e9.1 for ; Mon, 19 Aug 2024 08:50:52 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724082651; x=1724687451; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=pVlbQyzSrmr80QP6wCh9uo/OrSot8fgSEiVruMsUdCI=; b=d2c62Iya6TADrd9kRI9NfiEtU4nnqcyi/ezvkf7s7YW1ekkn7ZmtEdAADxlskUeuWz t9bfI5CQcxXmuGhQXwGqZ3Djlt4tFfkXPiZCInKbaVEVHNRHv23F1vIFewudlFA/13tN ahS8iFBvSj/hB5+O2dQUELbPDr+JbZR9VnFwvPC73eBM8HRWhS9pOhKCAxjeFJCFohES BXjtPdzYoGeABHZsGjnJsNhY7OCZzbZnOBEW7WYuvk9q4KLP2fVNuEtqWyfrBd/3RdNK SmaxqsdLlJCKO9aUkvibn+H4OCNSpU4VBZWt+hTQXixFmgUbbPGdkpHO+B/nrD6NAzOT Chdw== X-Gm-Message-State: AOJu0YygXmd1C8phvEvxiqz5vu+nHNyf44EDO0lDnyV92SiSj8MQN+P1 TaXa9XBDBQtWwJFblcyRWADX8WrXC9yXDPwtWdn2qYCL/uIm7YLAzPUJV84FxFAyHUo8frF1ZMn 2XGUkFgOYv0PABgsLrPmjqTVu5s3+A9ngL1uzyT9d7ZxtkXW/YLER+KuUJB4n X-Received: by 2002:a7b:c4d3:0:b0:428:e820:37ae with SMTP id 5b1f17b1804b1-429ed785f4dmr76219705e9.1.1724082651302; Mon, 19 Aug 2024 08:50:51 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHc1fHvqjqFAgWd0hgMnUiWy8tQvBncBWD7dEfy/zYRJxnM2dQpmmRGX3sfmFZH+KJuWbOnfg== X-Received: by 2002:a7b:c4d3:0:b0:428:e820:37ae with SMTP id 5b1f17b1804b1-429ed785f4dmr76211085e9.1.1724082623054; Mon, 19 Aug 2024 08:50:23 -0700 (PDT) Received: from redhat.com ([2a02:14f:1f1:5b3:2639:43bc:ddde:5f19]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-429ed78481asm115816095e9.32.2024.08.19.08.50.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Aug 2024 08:50:22 -0700 (PDT) Date: Mon, 19 Aug 2024 11:50:17 -0400 From: "Michael S. Tsirkin" To: Prasad Pandit Cc: qemu-devel@nongnu.org, farosas@suse.de, jasowang@redhat.com, mcoqueli@redhat.com, peterx@redhat.com, pjp@fedoraproject.org Subject: Re: [RFC-PATCH v2] vhost-user: add a request-reply lock Message-ID: <20240819114959-mutt-send-email-mst@kernel.org> References: <20240808095147.291626-3-ppandit@redhat.com> <20240819120248.170180-1-ppandit@redhat.com> <20240819114137-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240819114137-mutt-send-email-mst@kernel.org> Received-SPF: pass client-ip=170.10.133.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.134, 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_H4=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=ham 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 On Mon, Aug 19, 2024 at 11:42:02AM -0400, Michael S. Tsirkin wrote: > On Mon, Aug 19, 2024 at 05:32:48PM +0530, Prasad Pandit wrote: > > From: Prasad Pandit > > > > QEMU threads use vhost_user_write/read calls to send > > and receive request/reply messages from a vhost-user > > device. When multiple threads communicate with the > > same vhost-user device, they can receive each other's > > messages, resulting in an erroneous state. > > > > When fault_thread exits upon completion of Postcopy > > migration, it sends a 'postcopy_end' message to the > > vhost-user device. But sometimes 'postcopy_end' message > > is sent while vhost device is being setup via > > vhost_dev_start(). > > > > Thread-1 Thread-2 > > > > vhost_dev_start postcopy_ram_incoming_cleanup > > vhost_device_iotlb_miss postcopy_notify > > vhost_backend_update_device_iotlb vhost_user_postcopy_notifier > > vhost_user_send_device_iotlb_msg vhost_user_postcopy_end > > process_message_reply process_message_reply > > vhost_user_read vhost_user_read > > vhost_user_read_header vhost_user_read_header > > "Fail to update device iotlb" "Failed to receive reply to postcopy_end" > > > > This creates confusion when vhost-user device receives > > 'postcopy_end' message while it is trying to update > > IOTLB entries. > > > > vhost_user_read_header: > > 700871,700871: Failed to read msg header. Flags 0x0 instead of 0x5. > > vhost_device_iotlb_miss: > > 700871,700871: Fail to update device iotlb > > vhost_user_postcopy_end: > > 700871,700900: Failed to receive reply to postcopy_end > > vhost_user_read_header: > > 700871,700871: Failed to read msg header. Flags 0x0 instead of 0x5. > > > > Here fault thread seems to end the postcopy migration > > while another thread is starting the vhost-user device. > > > > Add a mutex lock to hold for one request-reply cycle > > and avoid such race condition. > > > > Fixes: 46343570c06e ("vhost+postcopy: Wire up POSTCOPY_END notify") > > Suggested-by: Peter Xu > > Signed-off-by: Prasad Pandit > > makes sense. > Acked-by: Michael S. Tsirkin > But do not post v2 as reply to v1 pls. Also, looks like this will replace Message-Id: <20240801124540.38774-1-xiangwencheng@dayudpu.com> correct? > > --- > > hw/virtio/vhost-user.c | 74 ++++++++++++++++++++++++++++++++++ > > include/hw/virtio/vhost-user.h | 3 ++ > > 2 files changed, 77 insertions(+) > > > > v2: > > - Place QEMU_LOCK_GUARD near the vhost_user_write() calls, holding > > the lock for longer fails some tests during rpmbuild(8). > > - rpmbuild(8) fails for some SRPMs, not all. RHEL-9 SRPM builds with > > this patch, whereas Fedora SRPM does not build. > > - The host OS also seems to affect rpmbuild(8). Some SRPMs build well > > on RHEL-9, but not on Fedora-40 machine. > > > > v1: https://lore.kernel.org/qemu-devel/20240808095147.291626-3-ppandit@redhat.com/#R > > > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > > index 00561daa06..7b030ae2cd 100644 > > --- a/hw/virtio/vhost-user.c > > +++ b/hw/virtio/vhost-user.c > > @@ -24,6 +24,7 @@ > > #include "qemu/main-loop.h" > > #include "qemu/uuid.h" > > #include "qemu/sockets.h" > > +#include "qemu/lockable.h" > > #include "sysemu/runstate.h" > > #include "sysemu/cryptodev.h" > > #include "migration/postcopy-ram.h" > > @@ -446,6 +447,10 @@ static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base, > > .hdr.size = sizeof(msg.payload.log), > > }; > > > > + struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > /* Send only once with first queue pair */ > > if (dev->vq_index != 0) { > > return 0; > > @@ -664,6 +669,7 @@ static int send_remove_regions(struct vhost_dev *dev, > > bool reply_supported) > > { > > struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > struct vhost_memory_region *shadow_reg; > > int i, fd, shadow_reg_idx, ret; > > ram_addr_t offset; > > @@ -685,6 +691,8 @@ static int send_remove_regions(struct vhost_dev *dev, > > vhost_user_fill_msg_region(®ion_buffer, shadow_reg, 0); > > msg->payload.mem_reg.region = region_buffer; > > > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, msg, NULL, 0); > > if (ret < 0) { > > return ret; > > @@ -718,6 +726,7 @@ static int send_add_regions(struct vhost_dev *dev, > > bool reply_supported, bool track_ramblocks) > > { > > struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > int i, fd, ret, reg_idx, reg_fd_idx; > > struct vhost_memory_region *reg; > > MemoryRegion *mr; > > @@ -746,6 +755,8 @@ static int send_add_regions(struct vhost_dev *dev, > > vhost_user_fill_msg_region(®ion_buffer, reg, offset); > > msg->payload.mem_reg.region = region_buffer; > > > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, msg, &fd, 1); > > if (ret < 0) { > > return ret; > > @@ -893,6 +904,7 @@ static int vhost_user_set_mem_table_postcopy(struct vhost_dev *dev, > > bool config_mem_slots) > > { > > struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > int fds[VHOST_MEMORY_BASELINE_NREGIONS]; > > size_t fd_num = 0; > > VhostUserMsg msg_reply; > > @@ -926,6 +938,8 @@ static int vhost_user_set_mem_table_postcopy(struct vhost_dev *dev, > > return ret; > > } > > > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, fds, fd_num); > > if (ret < 0) { > > return ret; > > @@ -1005,6 +1019,7 @@ static int vhost_user_set_mem_table(struct vhost_dev *dev, > > struct vhost_memory *mem) > > { > > struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > int fds[VHOST_MEMORY_BASELINE_NREGIONS]; > > size_t fd_num = 0; > > bool do_postcopy = u->postcopy_listen && u->postcopy_fd.handler; > > @@ -1044,6 +1059,8 @@ static int vhost_user_set_mem_table(struct vhost_dev *dev, > > return ret; > > } > > > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, fds, fd_num); > > if (ret < 0) { > > return ret; > > @@ -1089,6 +1106,10 @@ static int vhost_user_get_u64(struct vhost_dev *dev, int request, uint64_t *u64) > > return 0; > > } > > > > + struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > return ret; > > @@ -1138,6 +1159,10 @@ static int vhost_user_write_sync(struct vhost_dev *dev, VhostUserMsg *msg, > > } > > } > > > > +/* struct vhost_user *u = dev->opaque; > > + * struct VhostUserState *us = u->user; > > + * QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + */ > > ret = vhost_user_write(dev, msg, NULL, 0); > > if (ret < 0) { > > return ret; > > @@ -1277,6 +1302,8 @@ static int vhost_user_get_vring_base(struct vhost_dev *dev, > > .hdr.size = sizeof(msg.payload.state), > > }; > > struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > > > VhostUserHostNotifier *n = fetch_notifier(u->user, ring->index); > > if (n) { > > @@ -1669,6 +1696,9 @@ int vhost_user_get_shared_object(struct vhost_dev *dev, unsigned char *uuid, > > }; > > memcpy(msg.payload.object.uuid, uuid, sizeof(msg.payload.object.uuid)); > > > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > return ret; > > @@ -1889,6 +1919,9 @@ static int vhost_setup_backend_channel(struct vhost_dev *dev) > > msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK; > > } > > > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, &sv[1], 1); > > if (ret) { > > goto out; > > @@ -1993,6 +2026,9 @@ static int vhost_user_postcopy_advise(struct vhost_dev *dev, Error **errp) > > .hdr.flags = VHOST_USER_VERSION, > > }; > > > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > error_setg(errp, "Failed to send postcopy_advise to vhost"); > > @@ -2051,6 +2087,9 @@ static int vhost_user_postcopy_listen(struct vhost_dev *dev, Error **errp) > > > > trace_vhost_user_postcopy_listen(); > > > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > error_setg(errp, "Failed to send postcopy_listen to vhost"); > > @@ -2080,6 +2119,9 @@ static int vhost_user_postcopy_end(struct vhost_dev *dev, Error **errp) > > > > trace_vhost_user_postcopy_end_entry(); > > > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > error_setg(errp, "Failed to send postcopy_end to vhost"); > > @@ -2372,6 +2414,10 @@ static int vhost_user_net_set_mtu(struct vhost_dev *dev, uint16_t mtu) > > msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK; > > } > > > > + struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > return ret; > > @@ -2396,6 +2442,10 @@ static int vhost_user_send_device_iotlb_msg(struct vhost_dev *dev, > > .payload.iotlb = *imsg, > > }; > > > > + struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > return ret; > > @@ -2428,6 +2478,10 @@ static int vhost_user_get_config(struct vhost_dev *dev, uint8_t *config, > > > > assert(config_len <= VHOST_USER_MAX_CONFIG_SIZE); > > > > + struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > msg.payload.config.offset = 0; > > msg.payload.config.size = config_len; > > ret = vhost_user_write(dev, &msg, NULL, 0); > > @@ -2492,6 +2546,10 @@ static int vhost_user_set_config(struct vhost_dev *dev, const uint8_t *data, > > p = msg.payload.config.region; > > memcpy(p, data, size); > > > > + struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > return ret; > > @@ -2570,6 +2628,10 @@ static int vhost_user_crypto_create_session(struct vhost_dev *dev, > > } > > } > > > > + struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > msg.payload.session.op_code = backend_info->op_code; > > msg.payload.session.session_id = backend_info->session_id; > > ret = vhost_user_write(dev, &msg, NULL, 0); > > @@ -2662,6 +2724,9 @@ static int vhost_user_get_inflight_fd(struct vhost_dev *dev, > > return 0; > > } > > > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > return ret; > > @@ -2757,6 +2822,7 @@ bool vhost_user_init(VhostUserState *user, CharBackend *chr, Error **errp) > > user->memory_slots = 0; > > user->notifiers = g_ptr_array_new_full(VIRTIO_QUEUE_MAX / 4, > > &vhost_user_state_destroy); > > + qemu_mutex_init(&user->vhost_user_request_reply_lock); > > return true; > > } > > > > @@ -2769,6 +2835,7 @@ void vhost_user_cleanup(VhostUserState *user) > > user->notifiers = (GPtrArray *) g_ptr_array_free(user->notifiers, true); > > memory_region_transaction_commit(); > > user->chr = NULL; > > + qemu_mutex_destroy(&user->vhost_user_request_reply_lock); > > } > > > > > > @@ -2902,6 +2969,9 @@ static int vhost_user_set_device_state_fd(struct vhost_dev *dev, > > return -ENOTSUP; > > } > > > > + struct VhostUserState *us = vu->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, &fd, 1); > > close(fd); > > if (ret < 0) { > > @@ -2965,6 +3035,10 @@ static int vhost_user_check_device_state(struct vhost_dev *dev, Error **errp) > > return -ENOTSUP; > > } > > > > + struct vhost_user *u = dev->opaque; > > + struct VhostUserState *us = u->user; > > + QEMU_LOCK_GUARD(&us->vhost_user_request_reply_lock); > > + > > ret = vhost_user_write(dev, &msg, NULL, 0); > > if (ret < 0) { > > error_setg_errno(errp, -ret, > > diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h > > index 324cd8663a..e96f12d449 100644 > > --- a/include/hw/virtio/vhost-user.h > > +++ b/include/hw/virtio/vhost-user.h > > @@ -67,6 +67,9 @@ typedef struct VhostUserState { > > GPtrArray *notifiers; > > int memory_slots; > > bool supports_config; > > + > > + /* Hold lock for a request-reply cycle */ > > + QemuMutex vhost_user_request_reply_lock; > > } VhostUserState; > > > > /** > > -- > > 2.46.0