[Qemu-devel] [PATCH v1 0/6] s390x/tcg: fix some accesses using low address

[David Hildenbrand <david@redhat.com>]

Conny reported that a guest Linux currently spits out:
  "The s390-virtio transport is deprecated. Please switch to a modern host
  providing virtio-ccw."

This is strange, because we have no legacy virtio transport in QEMU :)

Main problem is, that a page is tested for acccess, and the test does not
fail. All memory access variants like stb_phys() will never fail. On
invalid memory, they simply do nothing.

Linux uses lura for this check. Let's introduce a _real MMU that handles
prefixing and can later be used for things like low address protection.

The other BUG is that a check for invalid memory is wrong. Therefore,
Patch 1 alone makes the guest crash when trying to initialize the
virtio transport. Crazy stuff.

David Hildenbrand (6):
  s390x/tcg: fix checking for invalid memory check
  s390x/tcg: add MMU for real addresses
  s390x/tcg: make lura(g) use the new _real mmu.
  s390x/tcg: make stora(g) use the new _real mmu
  s390x/tcg: make testblock use the new _real mmu
  s390x/tcg: make idte/ipte use the new _real mmu

 target/s390x/cpu.h         |  4 +++-
 target/s390x/excp_helper.c | 29 +++++++++++++++++++----------
 target/s390x/internal.h    |  2 ++
 target/s390x/mem_helper.c  | 36 +++++++++++-------------------------
 target/s390x/mmu_helper.c  | 19 +++++++++++++++++++
 target/s390x/translate.c   |  4 ----
 6 files changed, 54 insertions(+), 40 deletions(-)

-- 
2.13.5