Re: [PATCH v9 1/4] arm64: Add initial support for E0PD

On Wed, Jan 15, 2020 at 01:54:27PM +0000, Will Deacon wrote:

On Mon, Nov 11, 2019 at 06:52:40PM +0000, Mark Brown wrote:

quoted

+	   E0PD (part of the ARMv8.5 extensions) allows us to ensure
+	   that EL0 accesses made via TTBR1 always fault in constant time,
+	   providing benefits to KPTI with lower overhead and without
+	   disrupting legitimate access to kernel memory such as SPE.

This doesn't quite make sense to me, since E0PD doesn't really benefit
KPTI. Mind if I fold in the diff below?

-	   providing benefits to KPTI with lower overhead and without
-	   disrupting legitimate access to kernel memory such as SPE.
+	   providing similar benefits to KASLR as those provided by KPTI, but
+	   with lower overhead and without disrupting legitimate access to
+	   kernel memory such as SPE.

Yes, there was supposed to be a "similar" in there, must've got
dropped at some point during review I think.

Reviwed-by: Mark Brown [off-list ref]