Re: [PATCH v5 11/17] arm64: docs: document pointer authentication

From: Marc Zyngier
Date: Fri Oct 19 2018 - 07:47:26 EST

On 19/10/18 12:35, Catalin Marinas wrote:
> On Tue, Oct 16, 2018 at 05:14:39PM +0100, Kristina Martsenko wrote:
>> On 05/10/2018 10:04, Ramana Radhakrishnan wrote:
>>> On 05/10/2018 09:47, Kristina Martsenko wrote:


>> The other option is to turn off trapping entirely. However then on a
>> big.LITTLE system with mismatched pointer authentication support
>> instructions will work intermittently on some CPUs but not others.
> That's another case but let's assume we never see such configurations ;).

I'd like to put it on the record that I'm not willing to support such a
configuration. So my ask is that if we detect a system where only some
of the CPUs have pointer authentication support, we either:

1) prevent some of the CPUs from booting (that's harsh)
2) disable KVM (that's easy)

I'm perfectly happy with (2).


Jazz is not dead. It just smells funny...