[RFC 0/2] powerpc/mm: Mark memory contexts requiring global TLBIs

[Frederic Barrat <fbarrat@linux.vnet.ibm.com>]

capi2 and opencapi require the TLB invalidations being sent for
addresses used on the cxl adapter or opencapi device to be global, as
there's a translation cache in the PSL (for capi2) or NPU (for
opencapi). The CAPP (for PSL) and NPU snoop the power bus.

This is not new: for the hash memory model, as soon as the cxl driver
is active, all local TLBIs become global. We need a similar mechanism
for the radix memory model. This patch tries to improve things a bit
by flagging the contexts requiring global TLBIs, therefore limiting
the "upgrade" and not affecting contexts not used by the card.

Alistair: for nvlink2, it is my understanding that all the required
invalidations are already in place through software mmio/ATSD, i.e. this
patch is not useful for you.

Submitting as an RFC, since I don't get to touch mmu.h everyday and
would like to probe people's reaction.



Frederic Barrat (2):
  powerpc/mm: Add marker for contexts requiring global TLB invalidations
  cxl: Mark context requiring global TLBIs

 arch/powerpc/include/asm/book3s/64/mmu.h |  9 +++++++++
 arch/powerpc/include/asm/tlb.h           | 10 ++++++++--
 arch/powerpc/mm/mmu_context_book3s64.c   |  1 +
 drivers/misc/cxl/api.c                   |  5 ++++-
 drivers/misc/cxl/file.c                  |  5 ++++-
 5 files changed, 26 insertions(+), 4 deletions(-)

-- 
2.11.0