Re: [PATCH v7 9/10] KVM: arm64: docs: document KVM support of pointer authentication

From: Amit Daniel Kachhap
Date: Wed Mar 27 2019 - 07:49:36 EST


Hi,

On 3/27/19 4:14 PM, Dave Martin wrote:
On Mon, Mar 25, 2019 at 08:05:49PM +0000, Kristina Martsenko wrote:
On 19/03/2019 08:30, Amit Daniel Kachhap wrote:
This adds sections for KVM API extension for pointer authentication.
A brief description about usage of pointer authentication for KVM guests
is added in the arm64 documentations.

Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Christoffer Dall <christoffer.dall@xxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: kvmarm@xxxxxxxxxxxxxxxxxxxxx

I think it makes sense to also update the Kconfig symbol description for
CONFIG_ARM64_PTR_AUTH, since it currently only mentions userspace
support, but now the option also enables KVM guest support.

It's also worth mentioning that CONFIG_ARM64_VHE=y is required for guest
support.

Is it worth making this dependency explicit in Kconfig?
Currently there is discrepancy that userspace supports ptrauth in both nVHE/VHE mode and KVM guest only in VHE mode. I suppose adding explicit dependency flag here makes both of them similar.

Thanks,
Amit D

For SVE, I have

config ARM64_SVE
depends on !KVM || ARM64_VHE

to implement this.

Cheers
---Dave