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=-18.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 CB4C0C2B9F4 for ; Thu, 17 Jun 2021 13:15:27 +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 621836109D for ; Thu, 17 Jun 2021 13:15:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 621836109D 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]:37082 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ltrri-0004zv-G4 for qemu-devel@archiver.kernel.org; Thu, 17 Jun 2021 09:15:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:38282) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ltrKE-0006s9-1U for qemu-devel@nongnu.org; Thu, 17 Jun 2021 08:40:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:46086) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ltrK9-0007Yh-K2 for qemu-devel@nongnu.org; Thu, 17 Jun 2021 08:40:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623933642; 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=CbTatx65hPONsj4IEQhjxR0s1QfLbugh5hJa4V3aJcI=; b=G2bCu71PccYXjdTVK00z2KVUMugUGw3XAoPVALzFR6rPCA5nBkngneD9aBq1muh0aiyuEF XmXuYMCEh2qpieX0byCJhTK861sFc7Ccf4sCt0ToanZdaSjhFg+TAwP1p1RyVMetXv5+VC r6Rh4KKbyztxaWGARx3uBr5Jj1Dy6X4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-542-ZGAh3nPHOaazd9u1zSTR_Q-1; Thu, 17 Jun 2021 08:40:39 -0400 X-MC-Unique: ZGAh3nPHOaazd9u1zSTR_Q-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 287738042AC; Thu, 17 Jun 2021 12:40:38 +0000 (UTC) Received: from starship (unknown [10.40.194.6]) by smtp.corp.redhat.com (Postfix) with ESMTP id B91AC60C05; Thu, 17 Jun 2021 12:40:17 +0000 (UTC) Message-ID: <4b6b6f1b7a97d4b7fd2008fd31c6c2121ba053fb.camel@redhat.com> Subject: Re: [PATCH] block/nvme: Fix VFIO_MAP_DMA failed: No space left on device From: Maxim Levitsky To: Philippe =?ISO-8859-1?Q?Mathieu-Daud=E9?= , qemu-devel@nongnu.org, Alex Williamson , Eric Auger Date: Thu, 17 Jun 2021 15:40:16 +0300 In-Reply-To: References: <20210611114606.320008-1-philmd@redhat.com> User-Agent: Evolution 3.36.5 (3.36.5-2.fc32) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mlevitsk@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=mlevitsk@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.197, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action 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: Fam Zheng , Kevin Wolf , qemu-block@nongnu.org, Michal =?ISO-8859-1?Q?Pr=EDvozn=EDk?= , qemu-stable@nongnu.org, Max Reitz , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, 2021-06-14 at 18:03 +0200, Philippe Mathieu-Daudé wrote: > On 6/11/21 1:46 PM, Philippe Mathieu-Daudé wrote: > > When the NVMe block driver was introduced (see commit bdd6a90a9e5, > > January 2018), Linux VFIO_IOMMU_MAP_DMA ioctl was only returning > > -ENOMEM in case of error. The driver was correctly handling the > > error path to recycle its volatile IOVA mappings. > > > > To fix CVE-2019-3882, Linux commit 492855939bdb ("vfio/type1: Limit > > DMA mappings per container", April 2019) added the -ENOSPC error to > > signal the user exhausted the DMA mappings available for a container. > > Hmm this commit has been added before v5.1-rc4. > > So while this fixes the behavior of v5.1-rc4+ kernels, > older kernels using this fix will have the same problem... Hi! I wonder why not to check for both -ENOMEM and -ENOSPC and recycle the mappings in both cases? I think that would work on both old and new kernels. What do you think? Best regards, Maxim Levitsky > > Should I check uname(2)'s utsname.release[]? Is it reliable? > > > The block driver started to mis-behave: > > > > qemu-system-x86_64: VFIO_MAP_DMA failed: No space left on device > > (qemu) > > (qemu) info status > > VM status: paused (io-error) > > (qemu) c > > VFIO_MAP_DMA failed: No space left on device > > qemu-system-x86_64: block/block-backend.c:1968: blk_get_aio_context: Assertion `ctx == blk->ctx' failed. > > > > Fix by handling the -ENOSPC error when DMA mappings are exhausted; > > other errors (such -ENOMEM) are still handled later in the same > > function. > > > > An easy way to reproduce this bug is to restrict the DMA mapping > > limit (65535 by default) when loading the VFIO IOMMU module: > > > > # modprobe vfio_iommu_type1 dma_entry_limit=666 > > > > Cc: qemu-stable@nongnu.org > > Reported-by: Michal Prívozník > > Fixes: bdd6a90a9e5 ("block: Add VFIO based NVMe driver") > > Buglink: https://bugs.launchpad.net/qemu/+bug/1863333 > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/65 > > Signed-off-by: Philippe Mathieu-Daudé > > --- > > Michal, is it still possible for you to test this (old bug)? > > > > A functional test using viommu & nested VM is planned (suggested by > > Stefan and Maxim). > > --- > > block/nvme.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/block/nvme.c b/block/nvme.c > > index 2b5421e7aa6..12f9dd5cce3 100644 > > --- a/block/nvme.c > > +++ b/block/nvme.c > > @@ -1030,7 +1030,7 @@ try_map: > > r = qemu_vfio_dma_map(s->vfio, > > qiov->iov[i].iov_base, > > len, true, &iova); > > - if (r == -ENOMEM && retry) { > > + if (r == -ENOSPC && retry) { > > retry = false; > > trace_nvme_dma_flush_queue_wait(s); > > if (s->dma_map_count) { > >