[PULL 92/97] hw/mem: cxl_type3: Add DC Region bitmap lock

[Michael S. Tsirkin]

From: Anisa Su <anisa...@samsung.com>

Add a lock on the bitmap of each CXLDCRegion in preparation for the next
patch which implements FMAPI Set DC Region Configuration. This command
can modify the block size, which means the region's bitmap must be updated
accordingly.

The lock becomes necessary when commands that add/release extents
(meaning they update the bitmap too) are enabled on a different CCI than
the CCI on which the FMAPI commands are enabled.

Reviewed-by: Fan Ni <fan...@samsung.com>
Signed-off-by: Anisa Su <anisa...@samsung.com>
Signed-off-by: Jonathan Cameron <jonathan.came...@huawei.com>
Message-Id: <20250714174509.1984430-7-jonathan.came...@huawei.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
 include/hw/cxl/cxl_device.h | 1 +
 hw/mem/cxl_type3.c          | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index 7e0a66906f..42ae5b7479 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -540,6 +540,7 @@ typedef struct CXLDCRegion {
     uint8_t flags;
     unsigned long *blk_bitmap;
     uint64_t supported_blk_size_bitmask;
+    QemuMutex bitmap_lock;
     /* Following bools make up dsmas flags, as defined in the CDAT */
     bool nonvolatile;
     bool sharable;
diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index 52d3910ed9..a7a1857a0c 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -692,6 +692,7 @@ static bool cxl_create_dc_regions(CXLType3Dev *ct3d, Error 
**errp)
         };
         ct3d->dc.total_capacity += region->len;
         region->blk_bitmap = bitmap_new(region->len / region->block_size);
+        qemu_mutex_init(&region->bitmap_lock);
     }
     QTAILQ_INIT(&ct3d->dc.extents);
     QTAILQ_INIT(&ct3d->dc.extents_pending);
@@ -1020,6 +1021,7 @@ void ct3_set_region_block_backed(CXLType3Dev *ct3d, 
uint64_t dpa,
         return;
     }
 
+    QEMU_LOCK_GUARD(&region->bitmap_lock);
     bitmap_set(region->blk_bitmap, (dpa - region->base) / region->block_size,
                len / region->block_size);
 }
@@ -1046,6 +1048,7 @@ bool ct3_test_region_block_backed(CXLType3Dev *ct3d, 
uint64_t dpa,
      * if bits between [dpa, dpa + len) are all 1s, meaning the DPA range is
      * backed with DC extents, return true; else return false.
      */
+    QEMU_LOCK_GUARD(&region->bitmap_lock);
     return find_next_zero_bit(region->blk_bitmap, nr + nbits, nr) == nr + 
nbits;
 }
 
@@ -1067,6 +1070,7 @@ void ct3_clear_region_block_backed(CXLType3Dev *ct3d, 
uint64_t dpa,
 
     nr = (dpa - region->base) / region->block_size;
     nbits = len / region->block_size;
+    QEMU_LOCK_GUARD(&region->bitmap_lock);
     bitmap_clear(region->blk_bitmap, nr, nbits);
 }
 
-- 
MST