Messages in this thread | | | Date | Wed, 11 Feb 2015 11:29:58 -0500 | From | Peter Jones <> | Subject | Re: [PATCH] x86, boot: Allow 64bit EFI kernel to be loaded above 4G |
| |
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
| |