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=-20.5 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,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 445B3C2B9F4 for ; Mon, 14 Jun 2021 16:05:49 +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 ADF0661245 for ; Mon, 14 Jun 2021 16:05:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ADF0661245 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]:46626 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lsp5v-0006UT-Pp for qemu-devel@archiver.kernel.org; Mon, 14 Jun 2021 12:05:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60124) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lsp3n-0004iB-Q5 for qemu-devel@nongnu.org; Mon, 14 Jun 2021 12:03:37 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:48773) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lsp3i-00062U-1a for qemu-devel@nongnu.org; Mon, 14 Jun 2021 12:03:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623686607; 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=8HMdULp8lBhHjEzIv2mOgG0hgD82TJM/+TnTi0S8uzo=; b=GFbtbbFkwFyhhoAosvf0qu1zptcf/+CSE3C9is4sStdqAEOzaAscHKNo9472vDaaFvu1Ga AOLntCTb05uRCmikFb6T0on1ZzGS4GWUstRxjpffkQMvooF8k9CcZqW+MO25y5+Bc3L1Zq AJTJg3Zx4QWo587lHgxPK6tIXtkQ6Qo= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-118-kI_E3HyXN0W6rJkwYeYgKw-1; Mon, 14 Jun 2021 12:03:25 -0400 X-MC-Unique: kI_E3HyXN0W6rJkwYeYgKw-1 Received: by mail-wr1-f69.google.com with SMTP id h104-20020adf90710000b029010de8455a3aso7231377wrh.12 for ; Mon, 14 Jun 2021 09:03:24 -0700 (PDT) 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=8HMdULp8lBhHjEzIv2mOgG0hgD82TJM/+TnTi0S8uzo=; b=BdViafj9f2ppjj11yzypMGHVroNPXt1kzR3d+jf78WIXoYGu1mnR1fZgptDLmlJGTn IBuC/df08HXMWIFMsTmggKe8nBTXoEJhUdv8nGFQ52OZI9WKJSug1mDTCT5bn+R1u/M8 zbA5tlyVz6SaG4xUBZdHOevXiiYWKY3C3rFebjD8umjDGF10l6cYT0Anm/DA6ifQ7bN2 WwHI8p5TpZl6ts0MngBLm9RUAP1t/CujwGmME/TJD10c8rnjjjox8dYgRH9rvnD7VDD0 2sDnwheo0uvFbB0tECZx3KdLgeXjXSFr0nuWTIvo12FwGhKlgj4eLP5xJ6ItMt0USAgV GXFg== X-Gm-Message-State: AOAM532keIwReQBRD/4CvOjlc3W9dSdpn/y5dpMRZYxndf7A5wbLco/v QbCvV5YFr4CVnTAUm2SmIJYSChZrxw7KXzni04yhe7emSlgL9rAuYGlkzGpeBjzBuVPQZoj6Tn5 MSqKJOhQXxJF+VFY= X-Received: by 2002:a05:6000:1849:: with SMTP id c9mr20223243wri.140.1623686603846; Mon, 14 Jun 2021 09:03:23 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzU/u4VONZxttU7n08VkeAaM1i/KlW1IdMsKnUjMkkvW3CmXzX34FmOMtnVf9b5eT4H1RvY3A== X-Received: by 2002:a05:6000:1849:: with SMTP id c9mr20223203wri.140.1623686603611; Mon, 14 Jun 2021 09:03:23 -0700 (PDT) Received: from [192.168.1.36] (93.red-83-35-24.dynamicip.rima-tde.net. [83.35.24.93]) by smtp.gmail.com with ESMTPSA id p23sm12175073wmi.26.2021.06.14.09.03.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 14 Jun 2021 09:03:23 -0700 (PDT) Subject: Re: [PATCH] block/nvme: Fix VFIO_MAP_DMA failed: No space left on device To: qemu-devel@nongnu.org, Alex Williamson , Eric Auger References: <20210611114606.320008-1-philmd@redhat.com> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Message-ID: Date: Mon, 14 Jun 2021 18:03:22 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210611114606.320008-1-philmd@redhat.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=philmd@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=philmd@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.2, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.489, 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=ham 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, =?UTF-8?B?TWljaGFsIFByw612b3puw61r?= , qemu-stable@nongnu.org, Max Reitz , Stefan Hajnoczi , Maxim Levitsky Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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... 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) { >