Re: [PATCH v7 00/12] Enabling DCD emulation support in Qemu

[fan <nifan.cxl@gmail.com>]

On Tue, May 14, 2024 at 02:16:51AM +0000, Zhijian Li (Fujitsu) wrote:
> Hi Fan
> 
> 
> Do you have a newer instruction to play with the DCD. It seems that
> the instruction in RFC[0] doesn't work for current code.
> 
> [0] https://lore.kernel.org/all/20230511175609.2091136-1-fan.ni@samsung.com/
> 

For the testing, the only thing that has been changed for this series is
the QMP interface for add/release DC extents.

https://lore.kernel.org/linux-cxl/d708f7c8-2598-4a17-9cbb-935c6ae2a2be@fujitsu.com/T/#m05066f0098e976fb1c4b05db5e7ff7ca1bf27b1e

1. Add dynamic capacity extents:

For example, the command to add two continuous extents (each 128MiB long)
to region 0 (starting at DPA offset 0) looks like below:

{ "execute": "qmp_capabilities" }

{ "execute": "cxl-add-dynamic-capacity",
  "arguments": {
      "path": "/machine/peripheral/cxl-dcd0",
      "hid": 0,
      "selection-policy": 2,
      "region-id": 0,
      "tag": "",
      "extents": [
      {
          "offset": 0,
          "len": 134217728
      },
      {
          "offset": 134217728,
          "len": 134217728
      }
      ]
  }
}

2. Release dynamic capacity extents:

For example, the command to release an extent of size 128MiB from region 0
(DPA offset 128MiB) looks like below:

{ "execute": "cxl-release-dynamic-capacity",
  "arguments": {
      "path": "/machine/peripheral/cxl-dcd0",
      "hid": 0,
      "flags": 1,
      "region-id": 0,
      "tag": "",
      "extents": [
      {
          "offset": 134217728,
          "len": 134217728
      }
      ]
  }
}

btw, I have a wiki page to explain how to test CXL DCD with a tool I
wrote.
https://github.com/moking/moking.github.io/wiki/cxl%E2%80%90test%E2%80%90tool:-A-tool-to-ease-CXL-test-with-QEMU-setup%E2%80%90%E2%80%90Using-DCD-test-as-an-example

Let me know if you need more info for testing.


Fan

> 
> 
> On 19/04/2024 07:10, nifan.cxl@gmail.com wrote:
> > A git tree of this series can be found here (with one extra commit on top
> > for printing out accepted/pending extent list):
> > https://github.com/moking/qemu/tree/dcd-v7
> > 
> > v6->v7:
> > 
> > 1. Fixed the dvsec range register issue mentioned in the the cover letter in v6.
> >     Only relevant bits are set to mark the device ready (Patch 6). (Jonathan)
> > 2. Moved the if statement in cxl_setup_memory from Patch 6 to Patch 4. (Jonathan)
> > 3. Used MIN instead of if statement to get record_count in Patch 7. (Jonathan)
> > 4. Added "Reviewed-by" tag to Patch 7.
> > 5. Modified cxl_dc_extent_release_dry_run so the updated extent list can be
> >     reused in cmd_dcd_release_dyn_cap to simplify the process in Patch 8. (Jørgen)
> > 6. Added comments to indicate further "TODO" items in cmd_dcd_add_dyn_cap_rsp.
> >      (Jonathan)
> > 7. Avoided irrelevant code reformat in Patch 8. (Jonathan)
> > 8. Modified QMP interfaces for adding/releasing DC extents to allow passing
> >     tags, selection policy, flags in the interface. (Jonathan, Gregory)
> > 9. Redesigned the pending list so extents in the same requests are grouped
> >      together. A new data structure is introduced to represent "extent group"
> >      in pending list.  (Jonathan)
> > 10. Added support in QMP interface for "More" flag.
> > 11. Check "Forced removal" flag for release request and not let it pass through.
> > 12. Removed the dynamic capacity log type from CxlEventLog definition in cxl.json
> >     to avoid the side effect it may introduce to inject error to DC event log.
> >     (Jonathan)
> > 13. Hard coded the event log type to dynamic capacity event log in QMP
> >      interfaces. (Jonathan)
> > 14. Adding space in between "-1]". (Jonathan)
> > 15. Some minor comment fixes.
> > 
> > The code is tested with similar setup and has passed similar tests as listed
> > in the cover letter of v5[1] and v6[2].
> > Also, the code is tested with the latest DCD kernel patchset[3].
> > 
> > [1] Qemu DCD patchset v5: https://lore.kernel.org/linux-cxl/20240304194331.1586191-1-nifan.cxl@gmail.com/T/#t
> > [2] Qemu DCD patchset v6: https://lore.kernel.org/linux-cxl/20240325190339.696686-1-nifan.cxl@gmail.com/T/#t
> > [3] DCD kernel patches: https://lore.kernel.org/linux-cxl/20240324-dcd-type2-upstream-v1-0-b7b00d623625@intel.com/T/#m11c571e21c4fe17c7d04ec5c2c7bc7cbf2cd07e3
> > 
> > 
> > Fan Ni (12):
> >    hw/cxl/cxl-mailbox-utils: Add dc_event_log_size field to output
> >      payload of identify memory device command
> >    hw/cxl/cxl-mailbox-utils: Add dynamic capacity region representative
> >      and mailbox command support
> >    include/hw/cxl/cxl_device: Rename mem_size as static_mem_size for
> >      type3 memory devices
> >    hw/mem/cxl_type3: Add support to create DC regions to type3 memory
> >      devices
> >    hw/mem/cxl-type3: Refactor ct3_build_cdat_entries_for_mr to take mr
> >      size instead of mr as argument
> >    hw/mem/cxl_type3: Add host backend and address space handling for DC
> >      regions
> >    hw/mem/cxl_type3: Add DC extent list representative and get DC extent
> >      list mailbox support
> >    hw/cxl/cxl-mailbox-utils: Add mailbox commands to support add/release
> >      dynamic capacity response
> >    hw/cxl/events: Add qmp interfaces to add/release dynamic capacity
> >      extents
> >    hw/mem/cxl_type3: Add DPA range validation for accesses to DC regions
> >    hw/cxl/cxl-mailbox-utils: Add superset extent release mailbox support
> >    hw/mem/cxl_type3: Allow to release extent superset in QMP interface
> > 
> >   hw/cxl/cxl-mailbox-utils.c  | 620 ++++++++++++++++++++++++++++++++++-
> >   hw/mem/cxl_type3.c          | 633 +++++++++++++++++++++++++++++++++---
> >   hw/mem/cxl_type3_stubs.c    |  20 ++
> >   include/hw/cxl/cxl_device.h |  81 ++++-
> >   include/hw/cxl/cxl_events.h |  18 +
> >   qapi/cxl.json               |  69 ++++
> >   6 files changed, 1396 insertions(+), 45 deletions(-)
> >