---

yaml
---
r: 255289
b: refs/heads/master
c: 3c3ed48
h: refs/heads/master
i:
  255287: f26ce87
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6d7a5d1ea34495ecb1d608f0e40afba7776ee408
+refs/heads/master: 3c3ed482dc077a67903a58c9e1aedba1bb18c18a

trunk/Documentation/virtual/lguest/lguest.c

@@ -1095,9 +1095,10 @@ static void update_device_status(struct device *dev)
 		warnx("Device %s configuration FAILED", dev->name);
 		if (dev->running)
 			reset_device(dev);
-	} else if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK) {
-		if (!dev->running)
-			start_device(dev);
+	} else {
+		if (dev->running)
+			err(1, "Device %s features finalized twice", dev->name);
+		start_device(dev);
 	}
 }
 
@@ -1122,25 +1123,11 @@ static void handle_output(unsigned long addr)
 			return;
 		}
 
-		/*
-		 * Devices *can* be used before status is set to DRIVER_OK.
-		 * The original plan was that they would never do this: they
-		 * would always finish setting up their status bits before
-		 * actually touching the virtqueues.  In practice, we allowed
-		 * them to, and they do (eg. the disk probes for partition
-		 * tables as part of initialization).
-		 *
-		 * If we see this, we start the device: once it's running, we
-		 * expect the device to catch all the notifications.
-		 */
+		/* Devices should not be used before features are finalized. */
 		for (vq = i->vq; vq; vq = vq->next) {
 			if (addr != vq->config.pfn*getpagesize())
 				continue;
-			if (i->running)
-				errx(1, "Notification on running %s", i->name);
-			/* This just calls create_thread() for each virtqueue */
-			start_device(i);
-			return;
+			errx(1, "Notification on %s before setup!", i->name);
 		}
 	}
 

trunk/drivers/lguest/lguest_device.c

@@ -108,6 +108,17 @@ static u32 lg_get_features(struct virtio_device *vdev)
 	return features;
 }
 
+/*
+ * To notify on reset or feature finalization, we (ab)use the NOTIFY
+ * hypercall, with the descriptor address of the device.
+ */
+static void status_notify(struct virtio_device *vdev)
+{
+	unsigned long offset = (void *)to_lgdev(vdev)->desc - lguest_devices;
+
+	hcall(LHCALL_NOTIFY, (max_pfn << PAGE_SHIFT) + offset, 0, 0, 0);
+}
+
 /*
  * The virtio core takes the features the Host offers, and copies the ones
  * supported by the driver into the vdev->features array.  Once that's all
@@ -135,6 +146,9 @@ static void lg_finalize_features(struct virtio_device *vdev)
 		if (test_bit(i, vdev->features))
 			out_features[i / 8] |= (1 << (i % 8));
 	}
+
+	/* Tell Host we've finished with this device's feature negotiation */
+	status_notify(vdev);
 }
 
 /* Once they've found a field, getting a copy of it is easy. */
@@ -168,28 +182,21 @@ static u8 lg_get_status(struct virtio_device *vdev)
 	return to_lgdev(vdev)->desc->status;
 }
 
-/*
- * To notify on status updates, we (ab)use the NOTIFY hypercall, with the
- * descriptor address of the device.  A zero status means "reset".
- */
-static void set_status(struct virtio_device *vdev, u8 status)
-{
-	unsigned long offset = (void *)to_lgdev(vdev)->desc - lguest_devices;
-
-	/* We set the status. */
-	to_lgdev(vdev)->desc->status = status;
-	hcall(LHCALL_NOTIFY, (max_pfn << PAGE_SHIFT) + offset, 0, 0, 0);
-}
-
 static void lg_set_status(struct virtio_device *vdev, u8 status)
 {
 	BUG_ON(!status);
-	set_status(vdev, status);
+	to_lgdev(vdev)->desc->status = status;
+
+	/* Tell Host immediately if we failed. */
+	if (status & VIRTIO_CONFIG_S_FAILED)
+		status_notify(vdev);
 }
 
 static void lg_reset(struct virtio_device *vdev)
 {
-	set_status(vdev, 0);
+	/* 0 status means "reset" */
+	to_lgdev(vdev)->desc->status = 0;
+	status_notify(vdev);
 }
 
 /*