Re: Linux 6.11-rc1

[Peter Zijlstra <peterz@infradead.org>]

On Wed, Jul 31, 2024 at 03:22:53PM -0700, Guenter Roeck wrote:
> On 7/31/24 14:20, Peter Zijlstra wrote:
> > On Wed, Jul 31, 2024 at 07:26:04PM +0200, Thomas Gleixner wrote:
> > > On Wed, Jul 31 2024 at 18:51, Peter Zijlstra wrote:
> > > > On Wed, Jul 31, 2024 at 06:31:05PM +0200, Peter Zijlstra wrote:
> > > > Thomas, this all still relies on the full text section being PMD mapped,
> > > > and since we don't have ALIGN_ENTRY_TEXT_END and _etext has PAGE_SIZE
> > > > alignment, can't have a PAGE mapped tail which then doesn't get cloned?
> > > > 
> > > > Do we want to make pto_clone_entry_text() use PTI_LEVEL_KERNEL_IMAGE
> > > > such that it will clone whatever it has?
> > > 
> > > Yes, I think so.
> > 
> > The alternative is ripping that level thing out entirely, and simply
> > duplicate anything we find in the page-tables.
> > 
> 
> The patch below (on top of the previous one, because otherwise it doesn't
> apply) causes qemu to bail out hard, with
> 
> ...
> [    3.658327] sr 2:0:0:0: Attached scsi generic sg0 type 5
> [    3.858040] sched_clock: Marking stable (3834034034, 23728553)->(3865222956, -7460369)
> [    3.861469] registered taskstats version 1
> [    3.861584] Loading compiled-in X.509 certificates
> [    4.082031] Btrfs loaded, zoned=no, fsverity=no
> [    4.096034] cryptomgr_test (69) used greatest stack depth: 6136 bytes left
> 
> No backtrace or other message, it just exits immediately.

Ha, I hadn't even compiled the thing :-) I was just wondering alound and
in patch form if the whole level thing was worth having in the first
place.

If it lives, I'll make sure to test it.

Thanks!