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

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

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;