Re: [PATCH] efi/capsule: Make efi_capsule_pending() lockless

From: One Thousand Gnomes
Date: Thu May 05 2016 - 10:56:28 EST

On Thu, 5 May 2016 15:36:43 +0100
Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx> wrote:

> On Thu, 05 May, at 02:27:16PM, Kweh, Hock Leong wrote:
> >
> > If not mistaken, the EFI firmware will not update a partially uploaded binary due to checksum error.
> > User is required to re-update the efi capsule again on the next boot up.
> Ah, so the capsule is only processed by the firmware after rebooting?
> That makes sense and alleviates my concerns about rebooting while in
> the middle of efi_capsule_update().

Yes - and in many cases the actions the firmware capsule update does are
done in a manner which once you exit the firmware cannot be done by the
OS. It acts as a way to communicate a block of (typically signed)
firmware to more hardware priviliged boot firmware.