From: Peter Jones <pjones@redhat.com>
To: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Yinghai Lu <yinghai@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Junjie Mao <eternal.n08@gmail.com>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Matthew Garrett <mjg59@srcf.ucam.org>
Subject: Re: [PATCH] x86, boot: Allow 64bit EFI kernel to be loaded above 4G
Date: Wed, 11 Feb 2015 11:29:58 -0500 [thread overview]
Message-ID: <20150211162958.GA18062@fenchurch.internal.datastacks.com> (raw)
In-Reply-To: <20150211155524.GC4665@codeblueprint.co.uk>
On Wed, Feb 11, 2015 at 03:55:24PM +0000, Matt Fleming wrote:
> On Mon, 09 Feb, at 12:23:15PM, Yinghai Lu wrote:
> > On Mon, Feb 9, 2015 at 10:27 AM, Matt Fleming <matt@codeblueprint.co.uk> wrote:
> > > On Tue, 03 Feb, at 06:03:20PM, Yinghai Lu wrote:
> > >
> > > The first thing that comes to mind is the issues we experienced last
> > > year when adding support for loading initrds above 4GB to the EFI boot
> > > stub, c.f. commit 47226ad4f4cf ("x86/efi: Only load initrd above 4g on
> > > second try").
> > >
> > > Are things going to work correctly this time?
> >
> > That should be addressed the grub2.
>
> I vaguely remember thinking that the issue was only experienced when
> using the EFI_FILE protocol, which grub2 doesn't use. So the grub
> developers may be OK, but we should at least give them a heads up.
Looks correct to me.
> > I was thinking that we may need to add mem_limit command together with
> > linuxefi and initrdefi.
> > or add linuxefi64/initrdefi64?
>
> No, we definitely do not want to add any more grub commands.
Definitely agree.
> > BTW, I tested loading kernel above grub2 on
> > virutalbox, qemu/kvm/OVMF, and real servers (ami ...) all work without problem.
> >
> > wonder if we need have one black list for 64bit UEFI that does not
> > support access
> > memory above 4G.
>
> We have been successful, so far, in not introducing these kind of
> blacklists. It would be a shame to start now.
>From grub's point of view I'm not sure why we'd care - the pages kernel
and initramfs land in are both from the Boot Services allocator, so if the
machine doesn't support high addresses, they won't be there.
--
Peter
next prev parent reply other threads:[~2015-02-11 16:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-04 2:03 [PATCH] x86, boot: Allow 64bit EFI kernel to be loaded above 4G Yinghai Lu
2015-02-05 3:25 ` Dave Young
2015-02-05 5:25 ` Yinghai Lu
2015-02-05 6:09 ` Dave Young
2015-02-18 7:29 ` Yinghai Lu
2015-02-09 18:27 ` Matt Fleming
2015-02-09 20:23 ` Yinghai Lu
[not found] ` <CAE9FiQUFO4yfEVgGZ9U0Q-RaokFor1gMbKJ7As2vvqGVkqrDbw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-02-11 15:55 ` Matt Fleming
2015-02-11 16:29 ` Peter Jones [this message]
2015-02-12 14:59 ` Matt Fleming
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