Re: Design doc of adding ACPI support for arm64 on Xen - version 5

From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
To: Shannon Zhao <zhaoshenglong@huawei.com>
Cc: "Huangpeng (Peter)" <peter.huangpeng@huawei.com>,
	Hangaohuai <hangaohuai@huawei.com>,
	Ian Campbell <ian.campbell@citrix.com>,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	Shannon Zhao <shannon.zhao@linaro.org>,
	andrew@fubar.geek.nz, xen-devel <xen-devel@lists.xen.org>,
	Julien Grall <julien.grall@citrix.com>,
	Stefano Stabellini <stefano.stabellini@citrix.com>,
	David Vrabel <david.vrabel@citrix.com>,
	Jan Beulich <jbeulich@suse.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Parth Dixit <parth.dixit@linaro.org>,
	Christoffer Dall <christoffer.dall@linaro.org>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: Design doc of adding ACPI support for arm64 on Xen - version 5
Date: Mon, 7 Sep 2015 11:47:44 +0100	[thread overview]
Message-ID: <alpine.DEB.2.02.1509071147280.2672@kaball.uk.xensource.com> (raw)
In-Reply-To: <55ED0687.1070500@huawei.com>

On Mon, 7 Sep 2015, Shannon Zhao wrote:
> 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.

It looks like a good way forward to me