Re: [PATCH v3 1/1] KVM: arm64: Allow cacheable stage 2 mapping using VMA flags

[Jason Gunthorpe]

On Mon, Mar 10, 2025 at 11:54:52AM +0000, Marc Zyngier wrote:

> Which brings me to the next point: FWB is not discoverable from
> userspace. How do you expect a VMM to know what it can or cannot do?

If you add a check at memslot creation time then simply fail the
memslot.

There is nothing the VMM can do except completely fail. There is no
alternative path here where a cachable VMA can be safely made
non-cachable for the guest?

Jason