[Qemu-devel] [PATCH v4] spapr-vscsi: add task management

[Alexey Kardashevskiy <aik@ozlabs.ru>]

At the moment the guest kernel issues two types of task management
requests to the hypervisor - task about and lun reset. This adds
handling for these tasks. As spapr-vscsi starts calling scsi_req_cancel(),
free_request callback was implemented.

As virtio-vscsi, spapr-vscsi does not handle CLEAR_ACA either as CDB
control byte does not seem to be used at all so NACA bit is not
set to the guest so the guest has no good reason to call CLEAR_ACA task.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
2013/07/26:
* fixed error handling

2013/07/23:
* remove unnecessary free_request callback

2013/07/22:
* fixed LUN_RESET (it used to clear requests while it should reset a device)
* added handling of ABORT_TASK_SET/CLEAR_TASK_SET

---
 hw/scsi/spapr_vscsi.c | 103 ++++++++++++++++++++++++++++++++++++--------------
 hw/scsi/srp.h         |   7 ++++
 2 files changed, 82 insertions(+), 28 deletions(-)

diff --git a/hw/scsi/spapr_vscsi.c b/hw/scsi/spapr_vscsi.c
index 46f4455..2c09a88 100644
--- a/hw/scsi/spapr_vscsi.c
+++ b/hw/scsi/spapr_vscsi.c
@@ -117,6 +117,20 @@ static struct vscsi_req *vscsi_get_req(VSCSIState *s)
     return NULL;
 }
 
+static struct vscsi_req *vscsi_find_req(VSCSIState *s, uint64_t srp_tag)
+{
+    vscsi_req *req;
+    int i;
+
+    for (i = 0; i < VSCSI_REQ_LIMIT; i++) {
+        req = &s->reqs[i];
+        if (req->iu.srp.cmd.tag == srp_tag) {
+            return req;
+        }
+    }
+    return NULL;
+}
+
 static void vscsi_put_req(vscsi_req *req)
 {
     if (req->sreq != NULL) {
@@ -753,40 +767,73 @@ static int vscsi_queue_cmd(VSCSIState *s, vscsi_req *req)
 static int vscsi_process_tsk_mgmt(VSCSIState *s, vscsi_req *req)
 {
     union viosrp_iu *iu = &req->iu;
-    int fn;
+    vscsi_req *tmpreq;
+    int i, lun = 0, resp = SRP_TSK_MGMT_COMPLETE;
+    SCSIDevice *d;
 
     fprintf(stderr, "vscsi_process_tsk_mgmt %02x\n",
             iu->srp.tsk_mgmt.tsk_mgmt_func);
 
-    switch (iu->srp.tsk_mgmt.tsk_mgmt_func) {
-#if 0 /* We really don't deal with these for now */
-    case SRP_TSK_ABORT_TASK:
-        fn = ABORT_TASK;
-        break;
-    case SRP_TSK_ABORT_TASK_SET:
-        fn = ABORT_TASK_SET;
-        break;
-    case SRP_TSK_CLEAR_TASK_SET:
-        fn = CLEAR_TASK_SET;
-        break;
-    case SRP_TSK_LUN_RESET:
-        fn = LOGICAL_UNIT_RESET;
-        break;
-    case SRP_TSK_CLEAR_ACA:
-        fn = CLEAR_ACA;
-        break;
-#endif
-    default:
-        fn = 0;
-    }
-    if (fn) {
-        /* XXX Send/Handle target task management */
-        ;
+    d = vscsi_device_find(&s->bus, be64_to_cpu(req->iu.srp.tsk_mgmt.lun), &lun);
+    if (!d) {
+        resp = SRP_TSK_MGMT_FIELDS_INVALID;
     } else {
-        vscsi_makeup_sense(s, req, ILLEGAL_REQUEST, 0x20, 0);
-        vscsi_send_rsp(s, req, CHECK_CONDITION, 0, 0);
+        switch (iu->srp.tsk_mgmt.tsk_mgmt_func) {
+        case SRP_TSK_ABORT_TASK:
+            if (d->lun != lun) {
+                resp = SRP_TSK_MGMT_FIELDS_INVALID;
+                break;
+            }
+
+            tmpreq = vscsi_find_req(s, req->iu.srp.tsk_mgmt.task_tag);
+            if (tmpreq && tmpreq->sreq) {
+                assert(tmpreq->sreq->hba_private);
+                scsi_req_cancel(tmpreq->sreq);
+            }
+            break;
+
+        case SRP_TSK_LUN_RESET:
+            if (d->lun != lun) {
+                resp = SRP_TSK_MGMT_FIELDS_INVALID;
+                break;
+            }
+
+            qdev_reset_all(&d->qdev);
+            break;
+
+        case SRP_TSK_ABORT_TASK_SET:
+        case SRP_TSK_CLEAR_TASK_SET:
+            if (d->lun != lun) {
+                resp = SRP_TSK_MGMT_FIELDS_INVALID;
+                break;
+            }
+
+            for (i = 0; i < VSCSI_REQ_LIMIT; i++) {
+                tmpreq = &s->reqs[i];
+                if (tmpreq->iu.srp.cmd.lun != req->iu.srp.tsk_mgmt.lun) {
+                    continue;
+                }
+                if (!tmpreq->active || !tmpreq->sreq) {
+                    continue;
+                }
+                assert(tmpreq->sreq->hba_private);
+                scsi_req_cancel(tmpreq->sreq);
+            }
+            break;
+
+        case SRP_TSK_CLEAR_ACA:
+            resp = SRP_TSK_MGMT_NOT_SUPPORTED;
+            break;
+
+        default:
+            resp = SRP_TSK_MGMT_FIELDS_INVALID;
+            break;
+        }
     }
-    return !fn;
+
+    vscsi_send_rsp(s, req, resp, 0, 0);
+
+    return 1;
 }
 
 static int vscsi_handle_srp_req(VSCSIState *s, vscsi_req *req)
diff --git a/hw/scsi/srp.h b/hw/scsi/srp.h
index 5e0cad5..d27f31d 100644
--- a/hw/scsi/srp.h
+++ b/hw/scsi/srp.h
@@ -90,6 +90,13 @@ enum {
     SRP_REV16A_IB_IO_CLASS = 0x0100
 };
 
+enum {
+    SRP_TSK_MGMT_COMPLETE       = 0x00,
+    SRP_TSK_MGMT_FIELDS_INVALID = 0x02,
+    SRP_TSK_MGMT_NOT_SUPPORTED  = 0x04,
+    SRP_TSK_MGMT_FAILED         = 0x05
+};
+
 struct srp_direct_buf {
     uint64_t    va;
     uint32_t    key;
-- 
1.8.3.2