spapr-vscsi: add task management

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>
[Fix choice of UCSOLCNT vs. SCSOLCNT. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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) {
@@ -755,40 +769,91 @@ 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;
+    uint64_t tag = iu->srp.rsp.tag;
+    uint8_t sol_not = iu->srp.cmd.sol_not;
 
     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;
+    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 {
+        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;
+        }
     }
-    if (fn) {
-        /* XXX Send/Handle target task management */
-        ;
+
+    /* Compose the response here as  */
+    memset(iu, 0, sizeof(struct srp_rsp) + 4);
+    iu->srp.rsp.opcode = SRP_RSP;
+    iu->srp.rsp.req_lim_delta = cpu_to_be32(1);
+    iu->srp.rsp.tag = tag;
+    iu->srp.rsp.flags |= SRP_RSP_FLAG_RSPVALID;
+    iu->srp.rsp.resp_data_len = cpu_to_be32(4);
+    if (resp) {
+        iu->srp.rsp.sol_not = (sol_not & 0x04) >> 2;
     } else {
-        vscsi_makeup_sense(s, req, ILLEGAL_REQUEST, 0x20, 0);
-        vscsi_send_rsp(s, req, CHECK_CONDITION, 0, 0);
+        iu->srp.rsp.sol_not = (sol_not & 0x02) >> 1;
     }
-    return !fn;
+
+    iu->srp.rsp.status = GOOD;
+    iu->srp.rsp.data[3] = resp;
+
+    vscsi_send_iu(s, req, sizeof(iu->srp.rsp) + 4, VIOSRP_SRP_FORMAT);
+
+    return 1;
 }
 
 static int vscsi_handle_srp_req(VSCSIState *s, vscsi_req *req)

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;