From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=209.132.183.28; helo=mx1.redhat.com; envelope-from=lersek@redhat.com; receiver=edk2-devel@lists.01.org Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id ED5FD2035260B for ; Fri, 27 Oct 2017 09:06:01 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id CD719C0587E8; Fri, 27 Oct 2017 16:09:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com CD719C0587E8 Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=lersek@redhat.com Received: from lacos-laptop-7.usersys.redhat.com (ovpn-122-3.rdu2.redhat.com [10.10.122.3]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2D1205C54A; Fri, 27 Oct 2017 16:09:46 +0000 (UTC) From: Laszlo Ersek To: edk2-devel-01 Cc: Aleksei Kovura , Dann Frazier , Eric Dong , Star Zeng , Ard Biesheuvel References: <20171026154819.20865-1-lersek@redhat.com> Message-ID: Date: Fri, 27 Oct 2017 18:09:46 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20171026154819.20865-1-lersek@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Fri, 27 Oct 2017 16:09:48 +0000 (UTC) Subject: Re: [PATCH] MdeModulePkg/AtaAtapiPassThru: disable only BM-DMA at ExitBootServices() X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 Oct 2017 16:06:02 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 10/26/17 17:48, Laszlo Ersek wrote: > Clearing I/O port decoding in the PCI command register at > ExitBootServices() breaks IDE boot in Windows, on QEMU's "pc" (i440fx) > machine type. (AHCI boot on "q35" is unaffected.) Windows seems repeatedly > stuck, apparently waiting for a timeout of sorts. > > This is arguably a Windows bug; a native OS driver should not expect the > firmware to leave the PCI command register in any particular state. > > Strictly speaking, we only need to disable BM-DMA at ExitBootServices(), > in order to abort pending transfers to/from RAM, which is soon to be owned > by the OS. BM-DMA is also the only bit that's explicitly named by the UEFI > Driver Writers' Guide, for clearing at ExitBootServices(). > > I've verified that clearing only BM-DMA fixes the isse (boot time) on > i440fx, and does not regress q35/AHCI. > > Cc: Aleksei Kovura > Cc: Ard Biesheuvel > Cc: Dann Frazier > Cc: Eric Dong > Cc: Star Zeng > Reported-by: Aleksei Kovura > Reported-by: Dann Frazier > Reported-by: https://launchpad.net/~cjkrupp > Bisected-by: Dann Frazier > Bisected-by: https://launchpad.net/~cjkrupp > Suggested-by: Ard Biesheuvel > Suggested-by: Star Zeng > Ref: https://bugs.launchpad.net/ubuntu/+source/edk2/+bug/1725560 > Fixes: 6fb8ddd36bde45614b0a069528cdc97077835a74 > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Laszlo Ersek > --- > > Notes: > Repo: https://github.com/lersek/edk2.git > Branch: ata_disable_only_bmdma > > MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h | 3 +-- > MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c | 5 ++--- > 2 files changed, 3 insertions(+), 5 deletions(-) > > diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h > index 8d6eac706c0b..92c5bf2001cd 100644 > --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h > +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.h > @@ -123,8 +123,7 @@ typedef struct { > LIST_ENTRY NonBlockingTaskList; > > // > - // For disabling the device (especially Bus Master DMA) at > - // ExitBootServices(). > + // For disabling Bus Master DMA on the device at ExitBootServices(). > // > EFI_EVENT ExitBootEvent; > } ATA_ATAPI_PASS_THRU_INSTANCE; > diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c > index 09064dda18b7..e10e0d4e65f6 100644 > --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c > +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AtaAtapiPassThru.c > @@ -480,8 +480,7 @@ InitializeAtaAtapiPassThru ( > } > > /** > - Disable the device (especially Bus Master DMA) when exiting the boot > - services. > + Disable Bus Master DMA on the device when exiting the boot services. > > @param[in] Event Event for which this notification function is being > called. > @@ -506,7 +505,7 @@ AtaPassThruExitBootServices ( > PciIo->Attributes ( > PciIo, > EfiPciIoAttributeOperationDisable, > - Instance->EnabledPciAttributes, > + Instance->EnabledPciAttributes & EFI_PCI_IO_ATTRIBUTE_BUS_MASTER, > NULL > ); > } > Thanks Everyone for the feedback; I fixed the typo pointed out by Star and pushed the patch as commit 76fd5a660d70. Cheers Laszlo