Re: [Qemu RFC 0/7] Early enabling of DCD emulation in Qemu

[Ira Weiny <ira.weiny@intel.com>]

Fan Ni wrote:
> On Thu, May 11, 2023 at 05:56:40PM +0000, Fan Ni wrote:
> 
> FYI.
> 
> I have updated the patch series and sent out again.
> 
> I suggested anyone who are interested in DCD and using this patch series to
> use the new series. Quite a few things has been fixed.
> 
> https://lore.kernel.org/linux-cxl/20230724162313.34196-1-fan.ni@samsung.com/T/#t
> 
> Also, if you want to use the code repo directly, you can try
> 
> https://github.com/moking/qemu-dcd-preview-latest/tree/dcd-dev

Thanks for the branch!

I took a quick look and I don't see a resolution to the problem I
mentioned with non DCD devices being supported.[1]

[1] https://lore.kernel.org/all/6483946e8152f_f1132294a2@iweiny-mobl.notmuch/

Did you fix this in a different way?  If I don't add DC to my mem devices they
don't get probed properly.  I'm still looking into this with your new branch,
but I don't think DC commands should be in the CEL if the device does not
support it.

Also I get a build warning on this branch I had to fix[3] as my build is
treating warnings as errors.[2]

I don't think this fix is technically necessary as 'list' should never be NULL
that I can see.  But might be nice to check or just use my fix.

I'll try and get to a review once I get the DCD stuff out on the list again.

Ira


[2]
../hw/mem/cxl_type3.c: In function ‘qmp_cxl_process_dynamic_capacity_event.constprop’:
../hw/mem/cxl_type3.c:2063:28: error: ‘rid’ may be used uninitialized [-Werror=maybe-uninitialized]
 2063 |     dCap.updated_region_id = rid;
      |     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~
../hw/mem/cxl_type3.c:1987:13: note: ‘rid’ was declared here
 1987 |     uint8_t rid;
      |             ^~~
cc1: all warnings being treated as errors

[3]

diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index e67328780407..d25e6064f6c9 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -1984,7 +1984,7 @@ static void qmp_cxl_process_dynamic_capacity_event(const char *path,
     CXLDCExtentRecordList *list = records;
     CXLDCExtent_raw *extents;
     uint64_t dpa, len;
-    uint8_t rid;
+    uint8_t rid = 0;
     int i;
 
     if (!obj) {