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 EAF8821EA15B2 for ; Mon, 9 Oct 2017 08:51:12 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A91797E430; Mon, 9 Oct 2017 15:54:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com A91797E430 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=lersek@redhat.com Received: from lacos-laptop-7.usersys.redhat.com (ovpn-121-84.rdu2.redhat.com [10.10.121.84]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1E3716BC01; Mon, 9 Oct 2017 15:54:37 +0000 (UTC) To: Jian J Wang , edk2-devel@lists.01.org Cc: Michael Kinney , Ayellet Wolman , Jiewen Yao , Eric Dong , Star Zeng References: <20171009141722.992-1-jian.j.wang@intel.com> <20171009141722.992-7-jian.j.wang@intel.com> From: Laszlo Ersek Message-ID: Date: Mon, 9 Oct 2017 17:54:37 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20171009141722.992-7-jian.j.wang@intel.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 09 Oct 2017 15:54:39 +0000 (UTC) Subject: Re: [PATCH v4 6/6] OvmfPkg/QemuVideoDxe: Bypass NULL pointer detection during VBE SHIM installing 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: Mon, 09 Oct 2017 15:51:13 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 10/09/17 16:17, Jian J Wang wrote: > QemuVideoDxe driver will link VBE SHIM into page 0. If NULL pointer > detection is enabled, this driver will fail to load. NULL pointer detection > bypassing code is added to prevent such problem during boot. > > Please note that Windows 7 will try to access VBE SHIM during boot if it's > installed, and then cause boot failure. This can be fixed by setting BIT7 > of PcdNullPointerDetectionPropertyMask to disable NULL pointer detection > after EndOfDxe. As far as we know, there's no other OSs has such issue. > > Cc: Star Zeng > Cc: Eric Dong > Cc: Jiewen Yao > Cc: Michael Kinney > Cc: Ayellet Wolman > Suggested-by: Ayellet Wolman > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Jian J Wang > --- > OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf | 1 + > OvmfPkg/QemuVideoDxe/VbeShim.c | 14 ++++++++++++++ > 2 files changed, 15 insertions(+) > > diff --git a/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf b/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf > index 577e07b0a8..ff68c99e96 100644 > --- a/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf > +++ b/OvmfPkg/QemuVideoDxe/QemuVideoDxe.inf > @@ -77,3 +77,4 @@ > [Pcd] > gOptionRomPkgTokenSpaceGuid.PcdDriverSupportedEfiVersion > gUefiOvmfPkgTokenSpaceGuid.PcdOvmfHostBridgePciDevId > + gEfiMdeModulePkgTokenSpaceGuid.PcdNullPointerDetectionPropertyMask > diff --git a/OvmfPkg/QemuVideoDxe/VbeShim.c b/OvmfPkg/QemuVideoDxe/VbeShim.c > index e45a08e887..8ba5522cde 100644 > --- a/OvmfPkg/QemuVideoDxe/VbeShim.c > +++ b/OvmfPkg/QemuVideoDxe/VbeShim.c > @@ -75,6 +75,20 @@ InstallVbeShim ( > UINTN Printed; > VBE_MODE_INFO *VbeModeInfo; > > + if ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & (BIT0|BIT7)) == BIT0) { > + DEBUG (( > + DEBUG_WARN, > + "%a: page 0 protected, not installing VBE shim\n", > + __FUNCTION__ > + )); > + DEBUG (( > + DEBUG_WARN, > + "%a: page 0 protection prevents Windows 7 from booting anyway\n", > + __FUNCTION__ > + )); > + return; > + } > + > Segment0 = 0x00000; > SegmentC = 0xC0000; > SegmentF = 0xF0000; > If this patch is entirely identical to the previous version (v3), then you should have please picked up the review tags from Jordan and myself, the ones that you got for v3: http://mid.mail-archive.com/150696711831.2454.16712170525103415248@jljusten-skl http://mid.mail-archive.com/d1a20be5-8dbf-8ce6-1738-d03b330047cc@redhat.com This way we can quickly filter out already reviewed patches, and avoid re-reviewing when there are no changes. Your cover letter v4 0/6 also does not summarize the changes relative to v3; in the future please don't forget about that. Thanks Laszlo