From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shannon Zhao Subject: Re: Design doc of adding ACPI support for arm64 on Xen - version 5 Date: Mon, 7 Sep 2015 11:37:43 +0800 Message-ID: <55ED0687.1070500@huawei.com> References: <55E02DC5.4090202@huawei.com> <1441196311.26292.155.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1441196311.26292.155.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell , xen-devel , Christoffer Dall , Stefano Stabellini , Julien Grall , Stefano Stabellini , Jan Beulich , Parth Dixit , andrew@fubar.geek.nz, Boris Ostrovsky , David Vrabel , Roger Pau Monne Cc: Hangaohuai , "Huangpeng (Peter)" , Shannon Zhao List-Id: xen-devel@lists.xenproject.org On 2015/9/2 20:18, Ian Campbell wrote: > On Fri, 2015-08-28 at 17:45 +0800, Shannon Zhao wrote: >> >> 1. Create minimal DT to pass required information to Dom0 >> ---------------------------------------------------------- >> The UEFI stub is a feature that extends the Image/zImage into a valid >> UEFI PE/COFF executable, including a loader application that makes it >> possible to load the kernel directly from the UEFI shell, boot menu, or >> one of the lightweight bootloaders like Gummiboot or rEFInd. >> The kernel image built with stub support remains a valid kernel image >> for booting in non-UEFI environments and the UEFI stub will be jumped >> over for non-UEFI environments. >> >> When booting in UEFI mode, the UEFI stub will create a minimal DT in >> order to pass the command line and other informations (such as the EFI >> memory table) to the kernel. And when booting with ACPI, kernel will get >> command line, ACPI root table address and memory map information from >> the minimal DT. Also, it will check if the DT contains only the /chosen >> node to know whether it boots with DT or ACPI. >> >> In addition, the current names of these properties with a "linux," >> prefix in the minimal DT are Linux specified. It needs to standardize >> them so that other OS(such as FreeBSD) could reuse them in the future. > > I mentioned this just now in a reply to an older revision while I was > catching up on my mail backlog but I think it is important enough to > reiterate here on the currently latest version: > > We need to discuss this possible standardisation of (some derivative of) > this Linux internal interfaces in the appropriate forums ASAP and come to a > wider agreement that it is acceptable than just here amongst us Xen people. > > A large part of this design is predicated on this and we don't want to get > too far down this path only to discover the rest of the world says "No, > thanks". > > See my earlier reply at > http://lists.xen.org/archives/html/xen-devel/2015-09/msg00189.html for some > thoughts as to who we should be talking to. > Can we start with the patch for dropping the prefix "linux," and send it to Linux kernel ML, Linux arm kernel ML, devicetree-spec and BSD ML? Explain why it needs to do the change and standardization. Base on this, we could discuss it with other people from the related fields. >> So we drop the "linux," prefix of UEFI parameters and change the names >> in Linux kernel as well. >> >> An example of the minimal DT: >> / { >> #address-cells = <2>; >> #size-cells = <1>; >> chosen { >> bootargs = "kernel=Image console=hvc0 earlycon=pl011,0x1c090000 >> root=/dev/vda2 rw rootfstype=ext4 init=/bin/sh acpi=force"; >> linux,initrd-start = <0xXXXXXXXX>; >> linux,initrd-end = <0xXXXXXXXX>; >> uefi-system-table = <0xXXXXXXXX>; >> uefi-mmap-start = <0xXXXXXXXX>; >> uefi-mmap-size = <0xXXXXXXXX>; >> uefi-mmap-desc-size = <0xXXXXXXXX>; >> uefi-mmap-desc-ver = <0xXXXXXXXX>; >> }; >> }; >> >> For details loook at >>> https://github.com/torvalds/linux/blob/master/Documentation/arm/uefi.txt > > > . > -- Shannon