diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h
index a91151c4a4fc..e95e5a516b5e 100644
--- a/drivers/scsi/cxlflash/common.h
+++ b/drivers/scsi/cxlflash/common.h
@@ -147,6 +147,7 @@ struct cxlflash_cfg {
 	wait_queue_head_t tmf_waitq;
 	spinlock_t tmf_slock;
 	bool tmf_active;
+	bool ws_unmap;		/* Write-same unmap supported */
 	wait_queue_head_t reset_waitq;
 	enum cxlflash_state state;
 	async_cookie_t async_reset_cookie;
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index d3ad52ec5314..0cce442c260a 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -1812,6 +1812,18 @@ static int init_global(struct cxlflash_cfg *cfg)
 			SISL_CTX_CAP_AFU_CMD | SISL_CTX_CAP_GSCSI_CMD),
 			&hwq->ctrl_map->ctx_cap);
 	}
+
+	/*
+	 * Determine write-same unmap support for host by evaluating the unmap
+	 * sector support bit of the context control register associated with
+	 * the primary hardware queue. Note that while this status is reflected
+	 * in a context register, the outcome can be assumed to be host-wide.
+	 */
+	hwq = get_hwq(afu, PRIMARY_HWQ);
+	reg = readq_be(&hwq->host_map->ctx_ctrl);
+	if (reg & SISL_CTX_CTRL_UNMAP_SECTOR)
+		cfg->ws_unmap = true;
+
 	/* Initialize heartbeat */
 	afu->hb = readq_be(&afu->afu_map->global.regs.afu_hb);
 out:
diff --git a/drivers/scsi/cxlflash/sislite.h b/drivers/scsi/cxlflash/sislite.h
index d671fae19697..09daa86670fc 100644
--- a/drivers/scsi/cxlflash/sislite.h
+++ b/drivers/scsi/cxlflash/sislite.h
@@ -283,6 +283,7 @@ struct sisl_host_map {
 	__be64 rrq_end;		/* write sequence: start followed by end */
 	__be64 cmd_room;
 	__be64 ctx_ctrl;	/* least significant byte or b56:63 is LISN# */
+#define SISL_CTX_CTRL_UNMAP_SECTOR	0x8000000000000000ULL /* b0 */
 	__be64 mbox_w;		/* restricted use */
 	__be64 sq_start;	/* Submission Queue (R/W): write sequence and */
 	__be64 sq_end;		/* inclusion semantics are the same as RRQ    */
diff --git a/drivers/scsi/cxlflash/vlun.c b/drivers/scsi/cxlflash/vlun.c
index 0800bcba5a00..bdfb93061460 100644
--- a/drivers/scsi/cxlflash/vlun.c
+++ b/drivers/scsi/cxlflash/vlun.c
@@ -446,6 +446,7 @@ static int write_same16(struct scsi_device *sdev,
 	while (left > 0) {
 
 		scsi_cmd[0] = WRITE_SAME_16;
+		scsi_cmd[1] = cfg->ws_unmap ? 0x8 : 0;
 		put_unaligned_be64(offset, &scsi_cmd[2]);
 		put_unaligned_be32(ws_limit < left ? ws_limit : left,
 				   &scsi_cmd[10]);