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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 48C99C25B48 for ; Tue, 24 Oct 2023 10:55:12 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qvF3L-0006N5-B5; Tue, 24 Oct 2023 06:54:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qvF3J-0006MK-4k; Tue, 24 Oct 2023 06:54:25 -0400 Received: from proxmox-new.maurer-it.com ([94.136.29.106]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qvF3B-0002Kz-AU; Tue, 24 Oct 2023 06:54:24 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 1F27344C0E; Tue, 24 Oct 2023 12:54:07 +0200 (CEST) Message-ID: <2ec675fb-0bd9-4f3d-b205-2a7fe5101427@proxmox.com> Date: Tue, 24 Oct 2023 12:54:06 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/2] hw/ide: reset: cancel async DMA operation before resetting state Content-Language: en-US From: Fiona Ebner To: qemu-devel@nongnu.org Cc: jsnow@redhat.com, thuth@redhat.com, lvivier@redhat.com, pbonzini@redhat.com, srowe@mose.org.uk, mike.maslenkin@gmail.com, qemu-block@nongnu.org, t.lamprecht@proxmox.com, a.lauterer@proxmox.com, philmd@linaro.org, kwolf@redhat.com References: <20230906130922.142845-1-f.ebner@proxmox.com> In-Reply-To: <20230906130922.142845-1-f.ebner@proxmox.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=94.136.29.106; envelope-from=f.ebner@proxmox.com; helo=proxmox-new.maurer-it.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, 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: 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 Ping Am 06.09.23 um 15:09 schrieb Fiona Ebner: > If there is a pending DMA operation during ide_bus_reset(), the fact > that the IDEState is already reset before the operation is canceled > can be problematic. In particular, ide_dma_cb() might be called and > then use the reset IDEState which contains the signature after the > reset. When used to construct the IO operation this leads to > ide_get_sector() returning 0 and nsector being 1. This is particularly > bad, because a write command will thus destroy the first sector which > often contains a partition table or similar. > > Traces showing the unsolicited write happening with IDEState > 0x5595af6949d0 being used after reset: > >> ahci_port_write ahci(0x5595af6923f0)[0]: port write [reg:PxSCTL] @ 0x2c: 0x00000300 >> ahci_reset_port ahci(0x5595af6923f0)[0]: reset port >> ide_reset IDEstate 0x5595af6949d0 >> ide_reset IDEstate 0x5595af694da8 >> ide_bus_reset_aio aio_cancel >> dma_aio_cancel dbs=0x7f64600089a0 >> dma_blk_cb dbs=0x7f64600089a0 ret=0 >> dma_complete dbs=0x7f64600089a0 ret=0 cb=0x5595acd40b30 >> ahci_populate_sglist ahci(0x5595af6923f0)[0] >> ahci_dma_prepare_buf ahci(0x5595af6923f0)[0]: prepare buf limit=512 prepared=512 >> ide_dma_cb IDEState 0x5595af6949d0; sector_num=0 n=1 cmd=DMA WRITE >> dma_blk_io dbs=0x7f6420802010 bs=0x5595ae2c6c30 offset=0 to_dev=1 >> dma_blk_cb dbs=0x7f6420802010 ret=0 > >> (gdb) p *qiov >> $11 = {iov = 0x7f647c76d840, niov = 1, {{nalloc = 1, local_iov = {iov_base = 0x0, >> iov_len = 512}}, {__pad = "\001\000\000\000\000\000\000\000\000\000\000", >> size = 512}}} >> (gdb) bt >> #0 blk_aio_pwritev (blk=0x5595ae2c6c30, offset=0, qiov=0x7f6420802070, flags=0, >> cb=0x5595ace6f0b0 , opaque=0x7f6420802010) >> at ../block/block-backend.c:1682 >> #1 0x00005595ace6f185 in dma_blk_cb (opaque=0x7f6420802010, ret=) >> at ../softmmu/dma-helpers.c:179 >> #2 0x00005595ace6f778 in dma_blk_io (ctx=0x5595ae0609f0, >> sg=sg@entry=0x5595af694d00, offset=offset@entry=0, align=align@entry=512, >> io_func=io_func@entry=0x5595ace6ee30 , >> io_func_opaque=io_func_opaque@entry=0x5595ae2c6c30, >> cb=0x5595acd40b30 , opaque=0x5595af6949d0, >> dir=DMA_DIRECTION_TO_DEVICE) at ../softmmu/dma-helpers.c:244 >> #3 0x00005595ace6f90a in dma_blk_write (blk=0x5595ae2c6c30, >> sg=sg@entry=0x5595af694d00, offset=offset@entry=0, align=align@entry=512, >> cb=cb@entry=0x5595acd40b30 , opaque=opaque@entry=0x5595af6949d0) >> at ../softmmu/dma-helpers.c:280 >> #4 0x00005595acd40e18 in ide_dma_cb (opaque=0x5595af6949d0, ret=) >> at ../hw/ide/core.c:953 >> #5 0x00005595ace6f319 in dma_complete (ret=0, dbs=0x7f64600089a0) >> at ../softmmu/dma-helpers.c:107 >> #6 dma_blk_cb (opaque=0x7f64600089a0, ret=0) at ../softmmu/dma-helpers.c:127 >> #7 0x00005595ad12227d in blk_aio_complete (acb=0x7f6460005b10) >> at ../block/block-backend.c:1527 >> #8 blk_aio_complete (acb=0x7f6460005b10) at ../block/block-backend.c:1524 >> #9 blk_aio_write_entry (opaque=0x7f6460005b10) at ../block/block-backend.c:1594 >> #10 0x00005595ad258cfb in coroutine_trampoline (i0=, >> i1=) at ../util/coroutine-ucontext.c:177 > > Signed-off-by: Fiona Ebner > Reviewed-by: Philippe Mathieu-Daudé