[Qemu-devel] [PATCH 0/4] introduce cpu_physical_memory_map_fast

[Paolo Bonzini <pbonzini@redhat.com>]

Paravirtualized devices (and also some real devices) can assume they
are going to access RAM.  For this reason, provide a fast-path
function with the following properties:

1) it will never allocate a bounce buffer

2) it can be used for read-modify-write operations

3) unlike qemu_get_ram_ptr, it is safe because it recognizes "short" blocks

Patches 3 and 4 use this function for virtio devices and the milkymist
GPU.  The latter is only compile-tested.

Another function checks if it is possible to split a contiguous physical
address range into multiple subranges, all of which use the fast path.
I will introduce later a use for this function.

Paolo Bonzini (4):
  exec: extract cpu_physical_memory_map_internal
  exec: introduce cpu_physical_memory_map_fast and
    cpu_physical_memory_map_check
  virtio: use cpu_physical_memory_map_fast
  milkymist: use cpu_physical_memory_map_fast

 cpu-common.h        |    4 ++
 exec.c              |  108 +++++++++++++++++++++++++++++++++++++-------------
 hw/milkymist-tmu2.c |   39 ++++++++++--------
 hw/vhost.c          |   10 ++--
 hw/virtio.c         |    2 +-
 5 files changed, 111 insertions(+), 52 deletions(-)

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1.7.4.4