From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: Re: MTRR setup in OVMF [was: PATCH v3 01/10 KVM: MMU: fix decoding cache type from MTRR] Date: Thu, 16 Jul 2015 03:30:38 +0800 Message-ID: <55A6B4DE.1040904@linux.intel.com> References: <1431499348-25188-1-git-send-email-guangrong.xiao@linux.intel.com> <1436722432.1391.347.camel@redhat.com> <55A2B8F7.1050805@linux.intel.com> <55A36976.6090807@redhat.com> <55A3CEF2.2030200@linux.intel.com> <55A3D57C.4050100@redhat.com> <55A3D616.8010209@linux.intel.com> <55A57B54.2040305@redhat.com> <922266674.41385307.1436908536320.JavaMail.zimbra@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Alex Williamson , gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, edk2-devel list , "Jordan Justen (Intel address)" To: Paolo Bonzini , Laszlo Ersek Return-path: In-Reply-To: <922266674.41385307.1436908536320.JavaMail.zimbra@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org Hi, I have posted the pachset to make OVMF happy and have CCed you guys, could you please check it if it works for you? On 07/15/2015 05:15 AM, Paolo Bonzini wrote: >> The long delay that Alex reported (for the case when all guest memory >> was set to UC up-front) is due to the fact that the SEC phase of OVMF >> decompresses an approximately 1712 KB sized, LZMA-compressed blob, to >> approx. 896 KB worth of PEI drivers and 8192 KB worth of DXE and UEFI >> drivers -- and this decompression is extremely memory-intensive. >> >> (When Jordan implemented that reset vector first, we saw similar >> performance degradation on AMD hosts (albeit not due to MTRR but due to >> page attributes). See >> . I'm only mentioning >> it here because it makes me appreciate the current problem report.) >> >> Anyway, the reset vector's page table building is implemented in >> "OvmfPkg/ResetVector/Ia32/PageTables64.asm". The decompression in SEC >> can be found in "OvmfPkg/Sec/SecMain.c", function DecompressMemFvs(). > > Perhaps the OVMF reset vector should initialize the MTRRs for the BSP? > I think SEC doesn't do any MMIO, so it should be enough to enable MTRRs > and set the default type to writeback. > > In any case we're going to have to quirk it, because of the broken > guests in the wild. > > Paolo >