[PATCH v7 11/12] hw/cxl/cxl-mailbox-utils: Add superset extent release mailbox support

[nifan . cxl]

From: Fan Ni <fan...@samsung.com>

With the change, we extend the extent release mailbox command processing
to allow more flexible release. As long as the DPA range of the extent to
release is covered by accepted extent(s) in the device, the release can be
performed.

Signed-off-by: Fan Ni <fan...@samsung.com>
---
 hw/cxl/cxl-mailbox-utils.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index 57f1ce9cce..89f0ab8116 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -1704,6 +1704,13 @@ static CXLRetCode 
cxl_dc_extent_release_dry_run(CXLType3Dev *ct3d,
         dpa = in->updated_entries[i].start_dpa;
         len = in->updated_entries[i].len;
 
+        /* Check if the DPA range is not fully backed with valid extents */
+        if (!ct3_test_region_block_backed(ct3d, dpa, len)) {
+            ret = CXL_MBOX_INVALID_PA;
+            goto free_and_exit;
+        }
+
+        /* After this point, extent overflow is the only error can happen */
         while (len > 0) {
             QTAILQ_FOREACH(ent, updated_list, node) {
                 range_init_nofail(&range, ent->start_dpa, ent->len);
@@ -1718,14 +1725,7 @@ static CXLRetCode 
cxl_dc_extent_release_dry_run(CXLType3Dev *ct3d,
                     if (range_contains(&range, dpa + len - 1)) {
                         len2 = ent_start_dpa + ent_len - dpa - len;
                     } else {
-                        /*
-                         * TODO: we reject the attempt to remove an extent
-                         * that overlaps with multiple extents in the device
-                         * for now. We will allow it once superset release
-                         * support is added.
-                         */
-                        ret = CXL_MBOX_INVALID_PA;
-                        goto free_and_exit;
+                        dpa = ent_start_dpa + ent_len;
                     }
                     len_done = ent_len - len1 - len2;
 
@@ -1752,14 +1752,9 @@ static CXLRetCode 
cxl_dc_extent_release_dry_run(CXLType3Dev *ct3d,
                     }
 
                     len -= len_done;
-                    /* len == 0 here until superset release is added */
                     break;
                 }
             }
-            if (len) {
-                ret = CXL_MBOX_INVALID_PA;
-                goto free_and_exit;
-            }
         }
     }
 free_and_exit:
-- 
2.43.0