Re: [PATCH v2 0/2] Rework secure memslot dropping

[Paul Mackerras <paulus@ozlabs.org>]

On Mon, Jul 27, 2020 at 12:24:27PM -0700, Ram Pai wrote:
> From: Laurent Dufour <ldufour@linux.ibm.com>
> 
> When doing memory hotplug on a secure VM, the secure pages are not well
> cleaned from the secure device when dropping the memslot.  This silent
> error, is then preventing the SVM to reboot properly after the following
> sequence of commands are run in the Qemu monitor:
> 
> device_add pc-dimm,id=dimm1,memdev=mem1
> device_del dimm1
> device_add pc-dimm,id=dimm1,memdev=mem1
> 
> At reboot time, when the kernel is booting again and switching to the
> secure mode, the page_in is failing for the pages in the memslot because
> the cleanup was not done properly, because the memslot is flagged as
> invalid during the hot unplug and thus the page fault mechanism is not
> triggered.
> 
> To prevent that during the memslot dropping, instead of belonging on the
> page fault mechanism to trigger the page out of the secured pages, it seems
> simpler to directly call the function doing the page out. This way the
> state of the memslot is not interfering on the page out process.
> 
> This series applies on top of the Ram's one titled:
> "[v6 0/5] Migrate non-migrated pages of a SVM."

Thanks, series applied to my kvm-ppc-next branch and pull request sent.

Paul.