1 files changed, 93 insertions, 0 deletions

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 2f84c5cff8d4..53a8600162a5 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -257,6 +257,70 @@ static void vmbus_process_offer(struct work_struct *work)
         }
 }
 
+enum {
+        IDE = 0,
+        SCSI,
+        NIC,
+        MAX_PERF_CHN,
+};
+
+/*
+ * This is an array of device_ids (device types) that are performance critical.
+ * We attempt to distribute the interrupt load for these devices across
+ * all available CPUs.
+ */
+static const struct hv_vmbus_device_id hp_devs[] = {
+        /* IDE */
+        { HV_IDE_GUID, },
+        /* Storage - SCSI */
+        { HV_SCSI_GUID, },
+        /* Network */
+        { HV_NIC_GUID, },
+};
+
+
+/*
+ * We use this state to statically distribute the channel interrupt load.
+ */
+static u32  next_vp;
+
+/*
+ * Starting with Win8, we can statically distribute the incoming
+ * channel interrupt load by binding a channel to VCPU. We
+ * implement here a simple round robin scheme for distributing
+ * the interrupt load.
+ * We will bind channels that are not performance critical to cpu 0 and
+ * performance critical channels (IDE, SCSI and Network) will be uniformly
+ * distributed across all available CPUs.
+ */
+static u32 get_vp_index(uuid_le *type_guid)
+{
+        u32 cur_cpu;
+        int i;
+        bool perf_chn = false;
+        u32 max_cpus = num_online_cpus();
+
+        for (i = IDE; i < MAX_PERF_CHN; i++) {
+                if (!memcmp(type_guid->b, hp_devs[i].guid,
+                                 sizeof(uuid_le))) {
+                        perf_chn = true;
+                        break;
+                }
+        }
+        if ((vmbus_proto_version == VERSION_WS2008) ||
+            (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
+                /*
+                 * Prior to win8, all channel interrupts are
+                 * delivered on cpu 0.
+                 * Also if the channel is not a performance critical
+                 * channel, bind it to cpu 0.
+                 */
+                return 0;
+        }
+        cur_cpu = (++next_vp % max_cpus);
+        return 0;
+}
+
 /*
  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
  *
@@ -275,6 +339,35 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
                 return;
         }
 
+        /*
+         * By default we setup state to enable batched
+         * reading. A specific service can choose to
+         * disable this prior to opening the channel.
+         */
+        newchannel->batched_reading = true;
+
+        /*
+         * Setup state for signalling the host.
+         */
+        newchannel->sig_event = (struct hv_input_signal_event *)
+                                (ALIGN((unsigned long)
+                                &newchannel->sig_buf,
+                                HV_HYPERCALL_PARAM_ALIGN));
+
+        newchannel->sig_event->connectionid.asu32 = 0;
+        newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
+        newchannel->sig_event->flag_number = 0;
+        newchannel->sig_event->rsvdz = 0;
+
+        if (vmbus_proto_version != VERSION_WS2008) {
+                newchannel->is_dedicated_interrupt =
+                                (offer->is_dedicated_interrupt != 0);
+                newchannel->sig_event->connectionid.u.id =
+                                offer->connection_id;
+        }
+
+        newchannel->target_vp = get_vp_index(&offer->offer.if_type);
+
         memcpy(&newchannel->offermsg, offer,
                sizeof(struct vmbus_channel_offer_channel));
         newchannel->monitor_grp = (u8)offer->monitorid / 32;