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 lists1p.gnu.org (lists1p.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 97971C61DB9 for ; Fri, 28 Aug 2026 06:12:43 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wzpmU-00027n-9m; Fri, 28 Aug 2026 02:09:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wzpmS-0001wS-Ew; Fri, 28 Aug 2026 02:09:36 -0400 Received: from sea.source.kernel.org ([172.234.252.31]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wzpmQ-00015M-It; Fri, 28 Aug 2026 02:09:36 -0400 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 45B584128D; Fri, 28 Aug 2026 06:09:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C6791F00A3E; Fri, 28 Aug 2026 06:09:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787897373; bh=PiCB9b98ZYL18/jX3YjWkrL88FZWuwQMKxh8fFKU+aA=; h=Date:Subject:From:To:Cc:References:In-Reply-To; b=bLGuYexq+ipzAwnNUdJrcNn814OP5RxyE8jYyzwuLP6UXKVk5f19dF+ZL07/uehdK MChR37cRa7x7lRma/gjTpTRdnJnFZTlOf7EoNLrdz9LdAvyPILAGhICiheu1OEvb/z kaLzsACKWJlrD/3nIbXeM1WUtskQtltTbn1yaW7evv+L6LpocKTktQQoUxF3921MST H1o9lsfs3hmCT92ZUUyheSf4uJLk2bMKMR1IV8HytfywV1xan1emPpRf6h30bvdSS2 Zy8nFMkMmAhnMMzfs5NV/i483qwaYCBgXMqUY+QFLl9F6cytB0mYZntGfXcsBUyKtG sO5NAZlRS/O4g== Message-ID: <137dfcd8-bfe8-47f3-826f-ba43aaa6da86@kernel.org> Date: Fri, 28 Aug 2026 15:09:30 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 05/12] virtio-blk: check the write granularity of writes to sequential zones From: Damien Le Moal To: Niklas Cassel , Stefan Hajnoczi , "Michael S. Tsirkin" , Kevin Wolf , Hanna Reitz Cc: Sam Li , qemu-block@nongnu.org, qemu-devel@nongnu.org References: <20260825205748.679968-1-cassel@kernel.org> <20260825205748.679968-6-cassel@kernel.org> Content-Language: en-US Organization: Western Digital Research In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=172.234.252.31; envelope-from=dlemoal@kernel.org; helo=sea.source.kernel.org X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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: 2.1.29 Precedence: list List-Id: qemu development 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 8/28/26 15:07, Damien Le Moal wrote: > On 8/26/26 05:57, Niklas Cassel wrote: >> All VIRTIO_BLK_T_OUT requests issued to sequential zones and all >> VIRTIO_BLK_T_ZONE_APPEND requests must have an offset and a data size >> that are multiples of the write granularity reported by the device >> (virtio 1.4, 5.2.6.1), and a violation is reported as >> VIRTIO_BLK_S_ZONE_UNALIGNED_WP (virtio 1.4, 5.2.6). >> >> Neither request type was fully checked. Zone appends validated only the >> offset, while writes were not checked at all. >> >> Check the size of the appended data, and both the offset and the size of >> a write, against blkconf_zone_write_granularity(), so that every request the >> device accepts is one that the guest driver was told is valid. Writes to >> conventional zones keep no alignment constraint beyond the logical block >> size. The write path performs the check after virtio_blk_sect_range_ok() >> so that the zone index derived from the guest supplied sector is known to >> be in range. >> >> Signed-off-by: Niklas Cassel >> --- >> hw/block/virtio-blk.c | 25 ++++++++++++++++++++++++- >> 1 file changed, 24 insertions(+), 1 deletion(-) >> >> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c >> index f8cda1baa7..7977f4abe5 100644 >> --- a/hw/block/virtio-blk.c >> +++ b/hw/block/virtio-blk.c >> @@ -522,7 +522,7 @@ static bool check_zoned_request(VirtIOBlock *s, int64_t offset, int64_t len, >> if (append) { >> uint32_t wg_mask = blkconf_zone_write_granularity(&s->conf.conf) - 1; >> >> - if (offset & wg_mask) { >> + if (offset & wg_mask || len & wg_mask) { >> *status = VIRTIO_BLK_S_ZONE_UNALIGNED_WP; >> return false; >> } >> @@ -911,6 +911,29 @@ static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) >> return 0; >> } >> >> + if (is_write) { >> + BlockDriverState *bs = blk_bs(s->blk); >> + int64_t offset = req->sector_num << BDRV_SECTOR_BITS; >> + uint32_t wg_mask = >> + blkconf_zone_write_granularity(&s->conf.conf) - 1; > > Getting this without having first checked that this is a write to a zoned disk > is odd... > >> + >> + /* >> + * Both the offset and the size of a write to a sequential zone >> + * must be a multiple of the write granularity reported by the >> + * device. Conventional zones are not constrained. The zone index >> + * is derived from a guest supplied sector, so this must come after >> + * virtio_blk_sect_range_ok() has bounded it. >> + */ >> + if (bs->bl.zoned != BLK_Z_NONE && > > "!=" ??? Why ? The write granularity alignment applies only to zoned disks, no? > So why is this not "bs->bl.zoned == BLK_Z_NONE" ? Doh! My bad. I was reading "NONE" as "ZONE"... 90 degrees off on the first letter rotation :) > >> + (offset & wg_mask || req->qiov.size & wg_mask) && >> + !BDRV_ZT_IS_CONV(bs->wps->wp[offset / bs->bl.zone_size])) { > > This condition is a little complex. A little inline helper > "virtio_blk_zoned_write_is_aligned()" or something like that would be nice. > >> + virtio_blk_req_complete(req, VIRTIO_BLK_S_ZONE_UNALIGNED_WP); >> + block_acct_invalid(blk_get_stats(s->blk), BLOCK_ACCT_WRITE); >> + g_free(req); >> + return 0; >> + } >> + } >> + >> block_acct_start(blk_get_stats(s->blk), &req->acct, req->qiov.size, >> is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ); >> > > -- Damien Le Moal Western Digital Research