Re: [RFC PATCH v2 20/23] KVM: arm64: Add arch vm ioctl hook

[Dave Martin <Dave.Martin@arm.com>]

On Fri, Nov 02, 2018 at 09:32:27AM +0100, Christoffer Dall wrote:
> On Fri, Sep 28, 2018 at 02:39:24PM +0100, Dave Martin wrote:
> > To enable arm64-specific vm ioctls to be added cleanly, this patch
> > adds a kvm_arm_arch_vm_ioctl() hook so that these don't pollute the
> > common code.
> 
> Hmmm, I don't really see the strenght of that argument, and have the
> same concern as before.  I'd like to avoid the additional indirection
> and instead just follow the existing pattern with a dummy implementation
> on the 32-bit side that returns an error.

So for this and the similar comment on patch 18, this was premature (or
at least, overzealous) factoring on my part.

I'm happy to merge this back together for arm and arm64 as you prefer.

Do we have a nice way of writing the arch check, e.g.

	case KVM_ARM_SVE_CONFIG:
		if (!IS_ENABLED(ARM64))
			return -EINVAL;
		else
			return kvm_vcpu_sve_config(NULL, userp);

should work, but looks a bit strange.  Maybe I'm just being fussy.

Is there a better way that I'm missing?

Cheers
---Dave