Re: [PATCH v4 00/10] Enabling DCD emulation support in Qemu

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

On Wed, Feb 21, 2024 at 10:15:53AM -0800, nifan.cxl@gmail.com wrote:
> From: Fan Ni <fan.ni@samsung.com>
> 
> v3[1]->v4: 
> 
> The code is rebased on mainstream QEMU with the following patch series:
> 
> hw/cxl/mailbox: change CCI cmd set structure to be a member, not a reference
> hw/cxl/mailbox: interface to add CCI commands to an existing CCI
> 
> Main changes include:
> 
> 1. Updated the specification references to align with cxl spec r3.1.
> 2. Add extra elements to get dc region configuration output payload and
> procecced accordingly in mailbox command 4800h.
> 3. Removed the unwanted space.
> 4. Refactored ct3_build_cdat_entries_for_mr and extract it as a separate patch.
> 5. Updated cxl_create_dc_regions function to derive region len from host
> backend size.
> 6. Changed the logic for creating DC regions when host backend and address
> space processing is introduced, now cxl_create_dc_regions is called only
> when host backend exists.
> 7. Updated the name of the definitions related to DC extents for consistency.
> 7. Updated dynamic capacity event record definition to align with spec r3.1.
> 9. Changed the dynamic capacity request process logic, for release request,
> extra checks are done against the pending list to remove the extent yet added.
> 10. Changed the return value of cxl_create_dc_regions so the return can be used
> to Remove the extent for the list if needed.
> 11. offset and size in the qmp interface are changed to be byte-wise while the
> original is MiB-wise.
> 12. Fixed bugs in handling bitmap for dpa range existence.
> 13. NOTE: in previous version DC is set to non-volatile, while in this version
> we change it to volatile per Jonathan's suggestion.
> 14. Updated the doc in qapi/cxl.json.
> 
> Thank Jonathan for the detailed review of the last version[1].
> 
> The code is tested with Ira's last kernel DCD patch set [2] with some minor
> bug fixes[3]. Tested operations include:
> 1. create DC region;
> 2. Add/release DC extents;
> 3. convert DC capacity into system RAM (no real read/write to DCD tested);
> 
> 
> v3: 
> [1] https://lore.kernel.org/linux-cxl/20231107180907.553451-1-nifan.cxl@gmail.com/T/#t
> [2] https://github.com/weiny2/linux-kernel/tree/dcd-v3-2023-10-30
> [3] https://github.com/moking/linux-dcd/commit/9d24fa6e5d39f934623220953caecc080f93e964
> 
> Fan Ni (10):
>   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 insead 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.c  | 507 +++++++++++++++++++++++++++++++-
>  hw/mem/cxl_type3.c          | 559 +++++++++++++++++++++++++++++++++---
>  hw/mem/cxl_type3_stubs.c    |  14 +
>  include/hw/cxl/cxl_device.h |  61 +++-
>  include/hw/cxl/cxl_events.h |  18 ++
>  qapi/cxl.json               |  61 +++-
>  6 files changed, 1174 insertions(+), 46 deletions(-)
> 
> -- 
> 2.43.0
> 

Hi,

I fixed some issues mentioned by Wonjae Lee (wj28.lee@gmail.com) in his
review comments and pushed the changes to my local tree:
https://github.com/moking/qemu/tree/dcd-v4

This is no functional changes to the code, mainly fixes include:
1. Did spell check for the patchset and fixed 2 typos;
2. Fixed a misuse of stq_le_p and replaced it with stl_le_p in
cmd_dcd_get_dyn_cap_config;
3. Removed unnecessary switch case in patch 9;
4. Capitalized ""opcode" to "Opcode" in two code comments;
5. Updated one reference text to the spec;
6. Minor text change in qapi/cxl.json.

Thanks Wonjae for the careful review.


I will wait until next week to send out v5 to see if there are further
comments to come in.

Fan