vmbus: add infrastructure to save/load vmbus requests

This can be allow to include controller-specific data while
saving/loading in-flight scsi requests of the vmbus scsi controller.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Signed-off-by: Jon Doron <arilou@gmail.com>
Message-Id: <20200424123444.3481728-7-arilou@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/hyperv/vmbus.c

@@ -1272,6 +1272,105 @@ void vmbus_free_req(void *req)
     g_free(req);
 }
 
+static const VMStateDescription vmstate_sgent = {
+    .name = "vmbus/sgentry",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(base, ScatterGatherEntry),
+        VMSTATE_UINT64(len, ScatterGatherEntry),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+typedef struct VMBusChanReqSave {
+    uint16_t chan_idx;
+    uint16_t pkt_type;
+    uint32_t msglen;
+    void *msg;
+    uint64_t transaction_id;
+    bool need_comp;
+    uint32_t num;
+    ScatterGatherEntry *sgl;
+} VMBusChanReqSave;
+
+static const VMStateDescription vmstate_vmbus_chan_req = {
+    .name = "vmbus/vmbus_chan_req",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT16(chan_idx, VMBusChanReqSave),
+        VMSTATE_UINT16(pkt_type, VMBusChanReqSave),
+        VMSTATE_UINT32(msglen, VMBusChanReqSave),
+        VMSTATE_VBUFFER_ALLOC_UINT32(msg, VMBusChanReqSave, 0, NULL, msglen),
+        VMSTATE_UINT64(transaction_id, VMBusChanReqSave),
+        VMSTATE_BOOL(need_comp, VMBusChanReqSave),
+        VMSTATE_UINT32(num, VMBusChanReqSave),
+        VMSTATE_STRUCT_VARRAY_POINTER_UINT32(sgl, VMBusChanReqSave, num,
+                                             vmstate_sgent, ScatterGatherEntry),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+void vmbus_save_req(QEMUFile *f, VMBusChanReq *req)
+{
+    VMBusChanReqSave req_save;
+
+    req_save.chan_idx = req->chan->subchan_idx;
+    req_save.pkt_type = req->pkt_type;
+    req_save.msglen = req->msglen;
+    req_save.msg = req->msg;
+    req_save.transaction_id = req->transaction_id;
+    req_save.need_comp = req->need_comp;
+    req_save.num = req->sgl.nsg;
+    req_save.sgl = g_memdup(req->sgl.sg,
+                            req_save.num * sizeof(ScatterGatherEntry));
+
+    vmstate_save_state(f, &vmstate_vmbus_chan_req, &req_save, NULL);
+
+    g_free(req_save.sgl);
+}
+
+void *vmbus_load_req(QEMUFile *f, VMBusDevice *dev, uint32_t size)
+{
+    VMBusChanReqSave req_save;
+    VMBusChanReq *req = NULL;
+    VMBusChannel *chan = NULL;
+    uint32_t i;
+
+    vmstate_load_state(f, &vmstate_vmbus_chan_req, &req_save, 0);
+
+    if (req_save.chan_idx >= dev->num_channels) {
+        error_report("%s: %u(chan_idx) > %u(num_channels)", __func__,
+                     req_save.chan_idx, dev->num_channels);
+        goto out;
+    }
+    chan = &dev->channels[req_save.chan_idx];
+
+    if (vmbus_channel_reserve(chan, 0, req_save.msglen)) {
+        goto out;
+    }
+
+    req = vmbus_alloc_req(chan, size, req_save.pkt_type, req_save.msglen,
+                          req_save.transaction_id, req_save.need_comp);
+    if (req_save.msglen) {
+        memcpy(req->msg, req_save.msg, req_save.msglen);
+    }
+
+    for (i = 0; i < req_save.num; i++) {
+        qemu_sglist_add(&req->sgl, req_save.sgl[i].base, req_save.sgl[i].len);
+    }
+
+out:
+    if (req_save.msglen) {
+        g_free(req_save.msg);
+    }
+    if (req_save.num) {
+        g_free(req_save.sgl);
+    }
+    return req;
+}
+
 static void channel_event_cb(EventNotifier *e)
 {
     VMBusChannel *chan = container_of(e, VMBusChannel, notifier);

include/hw/hyperv/vmbus.h

@@ -224,4 +224,7 @@ int vmbus_map_sgl(VMBusChanReq *req, DMADirection dir, struct iovec *iov,
 void vmbus_unmap_sgl(VMBusChanReq *req, DMADirection dir, struct iovec *iov,
                      unsigned iov_cnt, size_t accessed);
 
+void vmbus_save_req(QEMUFile *f, VMBusChanReq *req);
+void *vmbus_load_req(QEMUFile *f, VMBusDevice *dev, uint32_t size);
+
 #endif