nvmet: add support for reporting the host identifier

And fix the Get/Set Log Page implementation to take all 8 bits of the
feature identifier into account.
Signed-off-by: Omri Mann <omri@excelero.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
[hch: used the UUID API, updated changelog]

drivers/nvme/target/admin-cmd.c

@@ -443,7 +443,7 @@ static void nvmet_execute_set_features(struct nvmet_req *req)
 	u32 val32;
 	u16 status = 0;
 
-	switch (cdw10 & 0xf) {
+	switch (cdw10 & 0xff) {
 	case NVME_FEAT_NUM_QUEUES:
 		nvmet_set_result(req,
 			(subsys->max_qid - 1) | ((subsys->max_qid - 1) << 16));
@@ -453,6 +453,9 @@ static void nvmet_execute_set_features(struct nvmet_req *req)
 		req->sq->ctrl->kato = DIV_ROUND_UP(val32, 1000);
 		nvmet_set_result(req, req->sq->ctrl->kato);
 		break;
+	case NVME_FEAT_HOST_ID:
+		status = NVME_SC_CMD_SEQ_ERROR | NVME_SC_DNR;
+		break;
 	default:
 		status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 		break;
@@ -467,7 +470,7 @@ static void nvmet_execute_get_features(struct nvmet_req *req)
 	u32 cdw10 = le32_to_cpu(req->cmd->common.cdw10[0]);
 	u16 status = 0;
 
-	switch (cdw10 & 0xf) {
+	switch (cdw10 & 0xff) {
 	/*
 	 * These features are mandatory in the spec, but we don't
 	 * have a useful way to implement them.  We'll eventually
@@ -501,6 +504,16 @@ static void nvmet_execute_get_features(struct nvmet_req *req)
 	case NVME_FEAT_KATO:
 		nvmet_set_result(req, req->sq->ctrl->kato * 1000);
 		break;
+	case NVME_FEAT_HOST_ID:
+		/* need 128-bit host identifier flag */
+		if (!(req->cmd->common.cdw10[1] & cpu_to_le32(1 << 0))) {
+			status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
+			break;
+		}
+
+		status = nvmet_copy_to_sgl(req, 0, &req->sq->ctrl->hostid,
+				sizeof(req->sq->ctrl->hostid));
+		break;
 	default:
 		status = NVME_SC_INVALID_FIELD | NVME_SC_DNR;
 		break;

drivers/nvme/target/fabrics-cmd.c

@@ -154,6 +154,7 @@ static void nvmet_execute_admin_connect(struct nvmet_req *req)
 				  le32_to_cpu(c->kato), &ctrl);
 	if (status)
 		goto out;
+	uuid_copy(&ctrl->hostid, &d->hostid);
 
 	status = nvmet_install_queue(ctrl, req);
 	if (status) {

drivers/nvme/target/nvmet.h

@@ -115,6 +115,7 @@ struct nvmet_ctrl {
 	u32			cc;
 	u32			csts;
 
+	uuid_t			hostid;
 	u16			cntlid;
 	u32			kato;