powerpc/64: Disable use of radix under a hypervisor

[Michael Ellerman]

On Thu, 2017-02-16 at 02:49:21 UTC, Paul Mackerras wrote:
> Currently, if the kernel is running on a POWER9 processor under a
> hypervisor, it may try to use the radix MMU even though it doesn't have
> the necessary code to do so (it doesn't negotiate use of radix, and it
> doesn't do the H_REGISTER_PROC_TBL hcall).  If the hypervisor supports
> both radix and HPT, then it will set up the guest to use HPT (since the
> guest doesn't request radix in the CAS call), but if the radix feature
> bit is set in the ibm,pa-features property (which is valid, since
> ibm,pa-features is defined to represent the capabilities of the
> processor) the guest will try to use radix, resulting in a crash when
> it turns the MMU on.
> 
> This makes the minimal fix for the current code, which is to disable
> radix unless we are running in hypervisor mode.
> 
> Fixes: 2bfd65e45e87 ("powerpc/mm/radix: Add radix callbacks for early init routines")
> Cc: stable at vger.kernel.org # v4.7+
> Signed-off-by: Paul Mackerras <paulus at ozlabs.org>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/3f91a89d424a79f8082525db5a375e

cheers