[PATCH 0/2] KVM: arm64: Fixes for S2 permission relaxation

[Oliver Upton <oupton@kernel.org>]

Couple of small fixes for S2 permission relaxation.

The first patch looks a bit worse than it actually is, potentially
consuming an uninitialized stack variable as a TLBI TTL hint in the
event of a race to update the PTE. However, if the bad TTL value results
in the stale TLB entry remaining valid, the vCPU will just fault again
and (hopefully) avoid the race.

Second patch is of a similar flavor, where the permission relaxation was
unconditionally updating XN, potentially reaping execute permissions
when handling a write fault. The consequence of this is taking an
unintended execute permission fault to restore the original XN value.

Applies to 7.2-rc1.

Oliver Upton (2):
  KVM: arm64: Ensure level is always initialized when relaxing perms
  KVM: arm64: Only update XN attr when requested during S2 relaxation

 arch/arm64/kvm/hyp/pgtable.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)


base-commit: dc59e4fea9d83f03bad6bddf3fa2e52491777482
-- 
2.47.3