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 X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C2EEC2D0C0 for ; Mon, 23 Dec 2019 17:34:15 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 6B3D4206CB for ; Mon, 23 Dec 2019 17:34:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KzFWe7gP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B3D4206CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59688 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ijRaw-0003nL-Hm for qemu-devel@archiver.kernel.org; Mon, 23 Dec 2019 12:34:14 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59577) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ijRaC-0003M0-L7 for qemu-devel@nongnu.org; Mon, 23 Dec 2019 12:33:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ijRa9-0003Da-Of for qemu-devel@nongnu.org; Mon, 23 Dec 2019 12:33:27 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:58975 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ijRa9-0003CV-6W for qemu-devel@nongnu.org; Mon, 23 Dec 2019 12:33:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1577122404; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=opgjwRtickfdijUOpE58Dh8UuRUoO/s7wHN+GpNZAHM=; b=KzFWe7gPUWVYsuzsufxeDeSYqfTObnEbGo/rJNZZioqdGeGy90jnyLOF4Ll7fYIGVQmF/E 6zc3Xpo+pGg4pueshFA7ySlJqfzCwiGtyMY5XQ3MozDL7uI132XsNlZQPhoGIu6qawSm40 817Q2B3A/1cCTJB96ha+U3MIpqFTwnc= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-60-ArFvirIjMDO7sbhMQ871NA-1; Mon, 23 Dec 2019 12:33:22 -0500 Received: by mail-wr1-f72.google.com with SMTP id f15so2822248wrr.2 for ; Mon, 23 Dec 2019 09:33:22 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=opgjwRtickfdijUOpE58Dh8UuRUoO/s7wHN+GpNZAHM=; b=Y4CwHfcNtn75I45+yNphW5x9/GBaNy9NK3+Zh0eJqHOzZvHdFWBOFkx0NOg1DTj6PK Cyc5fFTduPrmt6cqKs2/rR0zFOhzmJY3MdXVUeZScXpHzKM08paKfQowQqu1FZdKPwhE EWQxFUu506qte63dJ8LoBG0H9YY+PWBrJ8LqBYkEKvbl7V5ZsIAI4NOGPBP7P3W9BFtV FQzBlNTHGNjtnxjIXV/NguMTNl5vAtgIlgsxn8+XKHw2htKbE+IgXt9NGUg7Uy8vWaqc KN4JIwaSDSL16yYuXlFkYqNgY0ticAAkFsLB83lN96Y1Q2ID9lh3wXaafMOKG2AxnIKr RAbg== X-Gm-Message-State: APjAAAWCowpmEJ2UizeeuHaQLk6f7npP3Scui1/iLbXP58u63C5L2Gq6 +LVQUO0NI07JoSiyJGF0Lu5jTOt5xxhBSVWq/SrsrbuYFZIx8ncgN95uh8Mf9scfEFVwbCCUPWI yJkG9/w6g0BTUcIs= X-Received: by 2002:a5d:4984:: with SMTP id r4mr29757112wrq.137.1577122400989; Mon, 23 Dec 2019 09:33:20 -0800 (PST) X-Google-Smtp-Source: APXvYqy51q8k8AS9NmNw7UbvW99bqsqYnSk5D25JOEsHWeIqUW1GjpjExCMN8idgIZCkCSYg+/NFuQ== X-Received: by 2002:a5d:4984:: with SMTP id r4mr29757096wrq.137.1577122400705; Mon, 23 Dec 2019 09:33:20 -0800 (PST) Received: from ?IPv6:2001:b07:6468:f312:ac09:bce1:1c26:264c? ([2001:b07:6468:f312:ac09:bce1:1c26:264c]) by smtp.gmail.com with ESMTPSA id j12sm21366366wrt.55.2019.12.23.09.33.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 23 Dec 2019 09:33:20 -0800 (PST) Subject: Re: [PATCH] virtio: add the queue number check To: "Michael S. Tsirkin" References: <20191223082813.28930-1-yang.zhong@intel.com> <5cb6ace0-dd8e-aa22-e280-1e697c2c4156@redhat.com> <20191223091856.GA8433@yangzhon-Virtual> <20191223092508-mutt-send-email-mst@kernel.org> From: Paolo Bonzini Message-ID: <187f02d9-1677-d232-a44a-ed7b1e5f6ee5@redhat.com> Date: Mon, 23 Dec 2019 18:33:26 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191223092508-mutt-send-email-mst@kernel.org> Content-Language: en-US X-MC-Unique: ArFvirIjMDO7sbhMQ871NA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Yang Zhong , qemu-devel@nongnu.org, Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 23/12/19 15:25, Michael S. Tsirkin wrote: > On Mon, Dec 23, 2019 at 12:02:18PM +0100, Paolo Bonzini wrote: >> On 23/12/19 10:18, Yang Zhong wrote: >>> In this time, the queue number in the front-end block driver is 2, but >>> the queue number in qemu side is still 4. So the guest virtio_blk >>> driver will failed to create vq with backend. >> >> Where? >> >>> There is no "set back" >>> mechnism for block driver to inform backend this new queue number. >>> So, i added this check in qemu side. >> >> Perhaps the guest kernel should still create the virtqueues, and just >> not use them. In any case, now that you have explained it, it is >> certainly a guest bug. > > Paolo do you understand where the bug is? No, I asked above where does the virtio_blk driver fail to create the virtqueues. But it shouldn't; it is legal for the guest not to configure all virtqueues, and QEMU knows to ignore the extra ones. For example, firmware can ignore virtio-scsi request queues above the first, or ignore the virtio-scsi control and event queues (see src/hw/virtio-scsi.c in SeaBIOS, it only calls vp_find_vq with index 2). In particular this is the reason why request queues for virtio-scsi are numbered 2 and above, rather than starting from zero: this way, the guest can just pretend that unnecessary queues do not exist, and still keep the virtqueue numbers consecutive. > E.g. I see this in vhost user block: > > /* Kick right away to begin processing requests already in vring */ > for (i = 0; i < s->dev.nvqs; i++) { > VirtQueue *kick_vq = virtio_get_queue(vdev, i); > > if (!virtio_queue_get_desc_addr(vdev, i)) { > continue; > } > event_notifier_set(virtio_queue_get_host_notifier(kick_vq)); > } > > which is an (admittedly hacky) want to skip VQs which > were not configured by guest .... Right, this is an example of QEMU ignoring extra virtqueues. Paolo > > >>> Since the current virtio-blk and vhost-user-blk device always >>> defaultly use 1 queue, it's hard to find this issue. >>> >>> I checked the guest kernel driver, virtio-scsi and virtio-blk all >>> have same check in their driver probe: >>> >>> num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs); >>> >>> It's possible the guest driver has different queue number with qemu >>> side. >>> >>> I also want to fix this issue from guest driver side, but currently there >>> is no better solution to fix this issue. >>> >>> By the way, i did not try scsi with this corner case, and only check >>> driver and qemu code to find same issue. thanks! >>> >>> Yang >>> >>>> Paolo >>>> >>>>> Signed-off-by: Yang Zhong >>>>> --- >>>>> hw/block/vhost-user-blk.c | 11 +++++++++++ >>>>> hw/block/virtio-blk.c | 11 ++++++++++- >>>>> hw/scsi/virtio-scsi.c | 12 ++++++++++++ >>>>> 3 files changed, 33 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c >>>>> index 63da9bb619..250e72abe4 100644 >>>>> --- a/hw/block/vhost-user-blk.c >>>>> +++ b/hw/block/vhost-user-blk.c >>>>> @@ -23,6 +23,8 @@ >>>>> #include "qom/object.h" >>>>> #include "hw/qdev-core.h" >>>>> #include "hw/qdev-properties.h" >>>>> +#include "qemu/option.h" >>>>> +#include "qemu/config-file.h" >>>>> #include "hw/virtio/vhost.h" >>>>> #include "hw/virtio/vhost-user-blk.h" >>>>> #include "hw/virtio/virtio.h" >>>>> @@ -391,6 +393,7 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp) >>>>> VirtIODevice *vdev = VIRTIO_DEVICE(dev); >>>>> VHostUserBlk *s = VHOST_USER_BLK(vdev); >>>>> Error *err = NULL; >>>>> + unsigned cpus; >>>>> int i, ret; >>>>> >>>>> if (!s->chardev.chr) { >>>>> @@ -403,6 +406,14 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp) >>>>> return; >>>>> } >>>>> >>>>> + cpus = qemu_opt_get_number(qemu_opts_find(qemu_find_opts("smp-opts"), NULL), >>>>> + "cpus", 0); >>>>> + if (s->num_queues > cpus ) { >>>>> + error_setg(errp, "vhost-user-blk: the queue number should be equal " >>>>> + "or less than vcpu number"); >>>>> + return; >>>>> + } >>>>> + >>>>> if (!s->queue_size) { >>>>> error_setg(errp, "vhost-user-blk: queue size must be non-zero"); >>>>> return; >>>>> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c >>>>> index d62e6377c2..b2f4d01148 100644 >>>>> --- a/hw/block/virtio-blk.c >>>>> +++ b/hw/block/virtio-blk.c >>>>> @@ -18,6 +18,8 @@ >>>>> #include "qemu/error-report.h" >>>>> #include "qemu/main-loop.h" >>>>> #include "trace.h" >>>>> +#include "qemu/option.h" >>>>> +#include "qemu/config-file.h" >>>>> #include "hw/block/block.h" >>>>> #include "hw/qdev-properties.h" >>>>> #include "sysemu/blockdev.h" >>>>> @@ -1119,7 +1121,7 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp) >>>>> VirtIOBlock *s = VIRTIO_BLK(dev); >>>>> VirtIOBlkConf *conf = &s->conf; >>>>> Error *err = NULL; >>>>> - unsigned i; >>>>> + unsigned i,cpus; >>>>> >>>>> if (!conf->conf.blk) { >>>>> error_setg(errp, "drive property not set"); >>>>> @@ -1133,6 +1135,13 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp) >>>>> error_setg(errp, "num-queues property must be larger than 0"); >>>>> return; >>>>> } >>>>> + cpus = qemu_opt_get_number(qemu_opts_find(qemu_find_opts("smp-opts"), NULL), >>>>> + "cpus", 0); >>>>> + if (conf->num_queues > cpus ) { >>>>> + error_setg(errp, "virtio-blk: the queue number should be equal " >>>>> + "or less than vcpu number"); >>>>> + return; >>>>> + } >>>>> if (!is_power_of_2(conf->queue_size) || >>>>> conf->queue_size > VIRTQUEUE_MAX_SIZE) { >>>>> error_setg(errp, "invalid queue-size property (%" PRIu16 "), " >>>>> diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c >>>>> index e8b2b64d09..8e3e44f6b9 100644 >>>>> --- a/hw/scsi/virtio-scsi.c >>>>> +++ b/hw/scsi/virtio-scsi.c >>>>> @@ -21,6 +21,8 @@ >>>>> #include "qemu/error-report.h" >>>>> #include "qemu/iov.h" >>>>> #include "qemu/module.h" >>>>> +#include "qemu/option.h" >>>>> +#include "qemu/config-file.h" >>>>> #include "sysemu/block-backend.h" >>>>> #include "hw/qdev-properties.h" >>>>> #include "hw/scsi/scsi.h" >>>>> @@ -880,6 +882,7 @@ void virtio_scsi_common_realize(DeviceState *dev, >>>>> { >>>>> VirtIODevice *vdev = VIRTIO_DEVICE(dev); >>>>> VirtIOSCSICommon *s = VIRTIO_SCSI_COMMON(dev); >>>>> + unsigned cpus; >>>>> int i; >>>>> >>>>> virtio_init(vdev, "virtio-scsi", VIRTIO_ID_SCSI, >>>>> @@ -893,6 +896,15 @@ void virtio_scsi_common_realize(DeviceState *dev, >>>>> virtio_cleanup(vdev); >>>>> return; >>>>> } >>>>> + >>>>> + cpus = qemu_opt_get_number(qemu_opts_find(qemu_find_opts("smp-opts"), NULL), >>>>> + "cpus", 0); >>>>> + if (s->conf.num_queues > cpus ) { >>>>> + error_setg(errp, "virtio-scsi: the queue number should be equal " >>>>> + "or less than vcpu number"); >>>>> + return; >>>>> + } >>>>> + >>>>> s->cmd_vqs = g_new0(VirtQueue *, s->conf.num_queues); >>>>> s->sense_size = VIRTIO_SCSI_SENSE_DEFAULT_SIZE; >>>>> s->cdb_size = VIRTIO_SCSI_CDB_DEFAULT_SIZE; >>>>> >>> >