On Mon, 27 Jul 2020 14:29:08 +0530, Aneesh Kumar K.V wrote:

This adds a kernel command line option that can be used to disable GTSE support.
Disabling GTSE implies kernel will make hcalls to invalidate TLB entries.

This was done so that we can do VM migration between configs that enable/disable
GTSE support via hypervisor. To migrate a VM from a system that supports
GTSE to a system that doesn't, we can boot the guest with
radix_hcall_invalidate=on, thereby forcing the guest to use hcalls for TLB
invalidates.

[...]

Applied to powerpc/next.

[1/1] powerpc/book3s64/radix: Add kernel command line option to disable radix GTSE
      https://git.kernel.org/powerpc/c/bf6b7661f41615c0815fce0a3f27acb5fc005470

cheers