On Sat, Jul 23, 2022 at 01:14:07PM +0200, Ard Biesheuvel wrote:

On Thu, 21 Jul 2022 at 19:13, Dave Hansen [off-list ref] wrote:

quoted

On 7/19/22 17:26, Marc Orr wrote:

quoted

- Dave's suggestion to "2. Boot some intermediate thing like a
bootloader that does acceptance ..." is pretty clever! So if upstream
thinks this FW-kernel negotiation is not a good direction, maybe we
(Google) can pursue this idea to avoid introducing yet another tag on
our images.

I'm obviously speaking only for myself here and not for "upstream" as a
whole, but I clearly don't like the FW/kernel negotiation thing.  It's a
permanent pain in our necks to solve a very temporary problem.

EFI is basically our existing embodiment of this fw/kernel negotiation
thing, and iff we need it, I have no objection to using it for this
purpose, i.e., to allow the firmware to infer whether or not it should
accept all available memory on behalf of the OS before exiting boot
services. But if we don't need this, even better.

FW/kernel negotiation does not work if there's a boot loader in the middle
that does ExitBootServices(). By the time kernel can announce if it
supports unaccepted memory there's nobody to announce to.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov