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 C6802C61DB9 for ; Fri, 28 Aug 2026 06:08:38 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wzpl3-0005kW-R3; Fri, 28 Aug 2026 02:08:09 -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 1wzpkz-0005ii-G7; Fri, 28 Aug 2026 02:08:05 -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 1wzpkx-0000rx-Oh; Fri, 28 Aug 2026 02:08:05 -0400 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id C42084034E; Fri, 28 Aug 2026 06:08:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1BD31F000E9; Fri, 28 Aug 2026 06:08:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787897281; bh=bqxzWgz2btkSRFknNgfQBDQkotarayQgcLuD9bMo+1k=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=RR0fuiwRlP7jFVu2almKXQ9K83IU3gyRaRu2cfyCaNJn1gYBt7Uuzi4TdmPS9W470 f6Nt0RJqSItrrdNUvzJuh275MaRlg+wH7gfVTbrpNIUZBb+qTyYO0URxC0fjy+xHRB WsmIUkcoZwvOcl2vLnGQGp2mwyjFZafMJPczGk/E2Kut30GTZ4BUVxKU/h++drivY3 XRHlSoGCid7zPPp9DaqspbHY41CRePwlR8c76LA7CU1OOwUTU7okv1VKdu/6XTdCZ4 H1sqioA8bBCpCQi+2xYjYxzvGm7dc2gwO5EcPMS01kANTpdEri+QAU/QDbDxmQtmkn jourQ9fr8Avuw== Message-ID: Date: Fri, 28 Aug 2026 15:07:59 +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 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 From: Damien Le Moal Organization: Western Digital Research In-Reply-To: <20260825205748.679968-6-cassel@kernel.org> 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 8/26/26 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" ? > + (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