[v2,0/3] hw/cxl: Support emulating 4 HDM decoders throughout topology

Message

Jonathan Cameron Sept. 7, 2023, 11:35 a.m. UTC

v2:
 - New patch to push previously static inline functions out of cxl_component.h
 - Add the CXL r3.0 expanded set of decoder counts - making it more obviously why
   a switch function makes sense.
 - Use computed difference in HDM1 and HDM0 decoder registers sets instead of
   0x20 / 4.
 - Style changes suggested by Philippe.

For initial CXL emulation / kernel driver bring up a single Host-managed
Device Memory (HDM) decoder instance was sufficient as it let us test the
basic region creation code etc. More complex testing appropriate today
requires a more realistic configuration with multiple decoders.

The Linux kernel will use separate decoders for each memory type (and
shortly per DCD region) and for each interleave set within a memory type
or DCD region. 4 decoders are sufficient for most test cases today but
we may need to grow these further in future.

This patch set already allowed us to identify one kernel bug which is
now fixed.
https://lore.kernel.org/linux-cxl/[e-mail]/

Note that, whilst I'm proposing this series for upstream (based on
priorities of what we have out of tree) it hasn't previously been posted
so needs review. (I failed to send it out previously)

Based on: [PATCH 0/4] hw/cxl: Minor CXL emulation fixes and cleanup
Based on: [PATCH v2 0/3] hw/cxl: Add dummy ACPI QTG DSM

Based on: Message ID: [e-mail]
Based on: Message ID: [e-mail]

Jonathan Cameron (3):
  hw/cxl: Push cxl_decoder_count_enc() and cxl_decode_ig() into .c
  hw/cxl: Add utility functions decoder interleave ways and target
    count.
  hw/cxl: Support 4 HDM decoders at all levels of topology

 include/hw/cxl/cxl_component.h |  30 +++++-----
 hw/cxl/cxl-component-utils.c   |  92 ++++++++++++++++++++++++++----
 hw/cxl/cxl-host.c              |  65 ++++++++++++++-------
 hw/mem/cxl_type3.c             | 100 +++++++++++++++++++++++----------
 4 files changed, 209 insertions(+), 78 deletions(-)