Re: [PATCH] xen/arm: Restricted access to IFSR32_EL2 and FPEXC32_EL2

[Ian Campbell <ian.campbell@citrix.com>]

On Wed, 2014-09-17 at 14:29 +0530, Vijay Kilari wrote:
> So questions are :
> 1) Is this the hypercall where domain type is set?.

For domU, yes.

> If so, can we return error for this hypercall if domU type is not supported by Xen?

I think that would indeed be the right thing to do.

In addition we need to modifiy arch_get_xen_caps to only include
xen-X.Y-armv7l in the result if the hardware does in fact support domU
as 32-bit. The toolstack will consult this when trying to figure out if
a domain can be built (I think the end result is that
XEN_DOMCTL_set_address_size should never fail because it should never be
called if it could fail, but add the check anyway)

> 2) Can xl tool allow to load domU that platform supports?. May be it require
>     hardware info here which may not be right way to do.

Not sure what you are asking here. If you try and build a 32-bit domain
on a 64-bit-only platform then the above changes will cause it to fail,
which is the right thing to happen. Does that answer your question?

Ian.