lkml.org 
[lkml]   [2020]   [Jan]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v2 4/4] efi: Fix handling of multiple efi_fake_mem= entries
On Tue, Dec 31, 2019 at 10:21 PM Dave Young <dyoung@redhat.com> wrote:
>
> > > Does kexec preserve iomem? I.e. as long as the initial translation of
> > > efi entries to e820, and resulting resource tree, is preserved by
> > > successive kexec cycles then I think we're ok.
> >
> > It will not preserve them automatically, but that can be fixed if
> > needed.
> >
> > There are two places:
> > 1. the in kernel loader, we can do similar with below commit (for Soft
> > Reseved instead):
> > commit 980621daf368f2b9aa69c7ea01baa654edb7577b
> > Author: Lianbo Jiang <lijiang@redhat.com>
> > Date: Tue Apr 23 09:30:07 2019 +0800
> >
> > x86/crash: Add e820 reserved ranges to kdump kernel's e820 table
>
> Oops, that is for kdump only, for kexec, should update the kexec e820
> table. But before doing that we need first to see if this is necessary.

We can cross that bridge later, but I expect it will eventually be
necessary. The soft-reservation facility will become more prevalent as
more platforms ship with DRAM differentiated memory ranges, like
high-bandwidth-memory, and the system needs to reserve it from general
kernel allocations. See commit 262b45ae3ab4 "x86/efi: EFI soft
reservation to E820 enumeration" and commit fe3e5e65c06e "efi:
Enumerate EFI_MEMORY_SP" for more details.

\
 
 \ /
  Last update: 2020-01-01 19:37    [W:0.087 / U:0.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site