lkml.org 
[lkml]   [2017]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCHv2 08/10] x86/mm: Replace compile-time checks for 5-level with runtime-time
On Wed, Jul 26, 2017 at 09:28:16AM +0200, Juergen Gross wrote:
> On 25/07/17 11:05, Kirill A. Shutemov wrote:
> > On Tue, Jul 18, 2017 at 04:24:06PM +0200, Juergen Gross wrote:
> >> Xen PV guests will never run with 5-level-paging enabled. So I guess you
> >> can drop the complete if (IS_ENABLED(CONFIG_X86_5LEVEL)) {} block.
> >
> > There is more code to drop from mmu_pv.c.
> >
> > But while there, I thought if with boot-time 5-level paging switching we
> > can allow kernel to compile with XEN_PV and XEN_PVH, so the kernel image
> > can be used in these XEN modes with 4-level paging.
> >
> > Could you check if with the patch below we can boot in XEN_PV and XEN_PVH
> > modes?
>
> We can't. I have used your branch:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/kas/linux.git
> la57/boot-switching/v2
>
> with this patch applied on top.
>
> Doesn't boot PV guest with X86_5LEVEL configured (very early crash).

Hm. Okay.

Have you tried PVH?

> Doesn't build with X86_5LEVEL not configured:
>
> AS arch/x86/kernel/head_64.o

I've fixed the patch and split the patch into two parts: cleanup and
re-enabling XEN_PV and XEN_PVH for X86_5LEVEL.

There's chance that I screw somthing up in clenaup part. Could you check
that?

--
Kirill A. Shutemov

\
 
 \ /
  Last update: 2017-07-26 18:43    [W:0.075 / U:2.788 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site