Re: [PATCH v20 03/14] KVM: arm64: Manage GCS access and registers for guests

On Mon, Sep 07, 2026 at 03:55:43PM +0100, Mark Brown wrote:

On Mon, Sep 07, 2026 at 03:14:34PM +0100, Lorenzo Stoakes (ARM) wrote:

quoted

On Fri, Sep 04, 2026 at 10:07:49PM +0100, Mark Brown wrote:

quoted

On Fri, Sep 04, 2026 at 09:54:51AM +0100, Lorenzo Stoakes (ARM) wrote:

quoted

quoted

I think the best thing overall would be to leave the runtime paths as
they are and refuse to run with an architecturally invalid setup, that
would avoid bloating the fast path.

quoted

Ack, it'd be nice to not have to worry about that.

quoted

Presumably we definitely want an oops on a GCS violation in general?

Yes, the guest is going to want GCS exceptions delivering if they've
enabled them and something triggers them.  It might also be relying on
the GCS for stack traces even if nothing triggers any GCS related fault.

OK so the answer seems definitely to be disallowing the invalid config at
runtime then I think! :)

--
Cheers, Lorenzo