Re: [PATCH] xen: CONFIG_PV_SHIM_EXCLUSIVE and CONFIG_HVM are mutually exclusive

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 08/12/2020 13:51, Juergen Gross wrote:
> With CONFIG_PV_SHIM_EXCLUSIVE some sources required for CONFIG_HVM are
> not built, so let CONFIG_HVM depend on !CONFIG_PV_SHIM_EXCLUSIVE.
>
> Let CONFIG_HVM default to !CONFIG_PV_SHIM instead.
>
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

So while this will fix the randconfig failure, the statement isn't
true.  There are HVM codepaths which aren't even dead in shim-exclusive
mode.

The problem here is the way CONFIG_PV_SHIM_EXCLUSIVE abuses the Kconfig
system.  What is currently happening is that this option is trying to
enforce the pv shim defconfig in the dependency system.

We already have a defconfig, which is used in appropriate locations.  We
should not have two different things fighting over control.

This is the fault of c/s 8b5b49ceb3d which went in despite my
objections.  The change is not related to PV_SHIM_EXCLUSIVE - it is to
do with not supporting a control domain, which a) better describes what
it is actually doing, and b) has wider utility than PV Shim.

~Andrew