On Fri, 21 Sep 2018 18:51:08 +0100, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote: > > On 21 September 2018 at 10:46, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > > On Fri, 21 Sep 2018 18:14:43 +0100, > > Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx> wrote: > >> > >> On 9/21/2018 10:32 AM, Ard Biesheuvel wrote: > >> > Add support for persistent memory reservations across kexec reboot on EFI > >> > systems by introducing a Linux-specific UEFI configuration table that points > >> > to a linked list in memory that can be augmented by each successive kexec > >> > kernel to describe regions in memory that the subsequent kernel should treat > >> > as reserved. > >> > > >> > The specific use case for this feature is GICv3 ARM systems that are not > >> > able to disable DMA access to LPI tables, meaning we have to reserve them > >> > and make the next kernel reuse the existing tables rather than allocating > >> > them from scratch. > >> > >> As far as I recall, Shanker Donthineni attempted to address a similar > >> (the same?) issue. I think we would be very interested, if that is > >> the case. > > > > Shanker's patches didn't solve the story of preserving the allocated > > memory across kexec, and were just expecting to get similar mappings. > > > > Ard's patches allow us to track the allocation, and to reuse those if > > it is safe to do so. > > > >> Is there another series that depends on these changes? If not, can > >> you describe the plan for this? > > > > I have a series which does exactly that[1], and that rely on Ard's > > patches. I'm about to post these patches now the dependency is public. > > > > FYI the efi_reserve_mem_region() function has been renamed to > efi_mem_reserve_persistent() Ah, indeed. Now fixed. Thanks, M. -- Jazz is not dead, it just smell funny.
