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-rw-r--r--hw/scsi-disk.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 3959603b0f..d621852857 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -1456,9 +1456,13 @@ static inline bool check_lba_range(SCSIDiskState *s,
* The first line tests that no overflow happens when computing the last
* sector. The second line tests that the last accessed sector is in
* range.
+ *
+ * Careful, the computations should not underflow for nb_sectors == 0,
+ * and a 0-block read to the first LBA beyond the end of device is
+ * valid.
*/
return (sector_num <= sector_num + nb_sectors &&
- sector_num + nb_sectors - 1 <= s->qdev.max_lba);
+ sector_num + nb_sectors <= s->qdev.max_lba + 1);
}
typedef struct UnmapCBData {