Re: [PATCH v14 2/5] hw/cxl: Make the CXL fixed memory windows devices.

[Itaru Kitayama <itaru.kitayama@linux.dev>]

On Thu, May 29, 2025 at 04:08:01PM +0100, Jonathan Cameron wrote:
> On Wed, 28 May 2025 12:07:23 +0100
> Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote:
> 
> > Previously these somewhat device like structures were tracked using a list
> > in the CXLState in each machine.  This is proving restrictive in a few
> > cases where we need to iterate through these without being aware of the
> > machine type. Just make them sysbus devices.
> > 
> > Restrict them to not user created as they need to be visible to early
> > stages of machine init given effects on the memory map.
> > 
> > This change both simplifies state tracking and enables features needed
> > for performance optimization and hotness tracking by making it possible
> > to retrieve the fixed memory window on actions elsewhere in the topology.
> > 
> > In some cases the ordering of the Fixed Memory Windows matters.
> > For those utility functions provide a GSList sorted by the window index.
> > This ensures that we get consistency across:
> > - ordering in the command line
> > - ordering of the host PA ranges
> > - ordering of ACPI CEDT structures describing the CFMWS.
> > 
> > Other aspects don't have this constraint. For those direct iteration
> > of the underlying hash structures is fine.
> > 
> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> I'll not post v15 for a while to give time for review, but I just realized
> this snippet was in a patch I was carrying on top of this and should have
> been in this patch.
> 
> diff --git a/include/hw/cxl/cxl.h b/include/hw/cxl/cxl.h
> index a610795c87..de66ab8c35 100644
> --- a/include/hw/cxl/cxl.h
> +++ b/include/hw/cxl/cxl.h
> @@ -46,7 +46,6 @@ typedef struct CXLState {
>      bool is_enabled;
>      MemoryRegion host_mr;
>      unsigned int next_mr_idx;
> -    GList *fixed_windows;
>      CXLFixedMemoryWindowOptionsList *cfmw_list;
>  } CXLState;

With this one line removed on top of v14, today's Dave's cxl/next kernel makes
cxl test suite ran through without a single failure.

Tested-by: Itaru Kitayama <itaru.kitayama@fujitsu.com>

Jonathan, Zhi jian of Fujitsu gave you feedback on the QEMU core CXL emulation code, 
are you still waiting on any other reviewers to take a look at the series v14 (or
v14-ish)?

Thanks,
Itaru.

>