Details about Low-Address Protection can be found in description of patch 1 and 2. It is basically a subpage protection of the first two pages of every address space (for which it is enabled).
We can achieve this by simply directly invalidating the TLB entry and therefore forcing every write accesses onto these two pages into the slow path. With this patch, I can boot Linux just fine (which uses LAP). This also makes all related kvm-unit-tests that we have pass. RFC -> v1: - fix LAP range check (Thomas) - SIGP fix got picked up Based on: https://github.com/cohuck/qemu.git s390-next Available on: https://github.com/dhildenb/qemu.git s390x_lap David Hildenbrand (2): accel/tcg: allow to invalidate a write TLB entry immediately s390x/tcg: low-address protection support accel/tcg/cputlb.c | 5 ++- accel/tcg/softmmu_template.h | 4 +- include/exec/cpu-all.h | 3 ++ target/s390x/excp_helper.c | 3 +- target/s390x/mem_helper.c | 8 ---- target/s390x/mmu_helper.c | 94 +++++++++++++++++++++++++++----------------- 6 files changed, 69 insertions(+), 48 deletions(-) -- 2.13.5
