[Stable-8.2.2 30/60] cxl/cdat: Handle cdat table build errors

[Michael Tokarev]

From: Ira Weiny <ira.weiny@intel.com>

The callback for building CDAT tables may return negative error codes.
This was previously unhandled and will result in potentially huge
allocations later on in ct3_build_cdat()

Detect the negative error code and defer cdat building.

Fixes: f5ee7413d592 ("hw/mem/cxl-type3: Add CXL CDAT Data Object Exchange")
Cc: Huai-Cheng Kuo <hchkuo@avery-design.com.tw>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20240126120132.24248-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit c62926f730d08450502d36548e28dd727c998ace)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/hw/cxl/cxl-cdat.c b/hw/cxl/cxl-cdat.c
index 639a2db3e1..24829cf242 100644
--- a/hw/cxl/cxl-cdat.c
+++ b/hw/cxl/cxl-cdat.c
@@ -63,7 +63,7 @@ static void ct3_build_cdat(CDATObject *cdat, Error **errp)
     cdat->built_buf_len = cdat->build_cdat_table(&cdat->built_buf,
                                                  cdat->private);
 
-    if (!cdat->built_buf_len) {
+    if (cdat->built_buf_len <= 0) {
         /* Build later as not all data available yet */
         cdat->to_update = true;
         return;
-- 
2.39.2