diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index 3be8ab2a886acf98e2b0a45ab3690fd20fc8bedc..82fafe0429fed8dc441411059be52b33154dd8a8 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -157,6 +157,9 @@ struct virtqueue
 
 	/* The routine to call when the Guest pings us. */
 	void (*handle_output)(int fd, struct virtqueue *me);
+
+	/* Outstanding buffers */
+	unsigned int inflight;
 };
 
 /* Remember the arguments to the program so we can "reboot" */
@@ -702,6 +705,7 @@ static unsigned get_vq_desc(struct virtqueue *vq,
 			errx(1, "Looped descriptor");
 	} while ((i = next_desc(vq, i)) != vq->vring.num);
 
+	vq->inflight++;
 	return head;
 }
 
@@ -719,6 +723,7 @@ static void add_used(struct virtqueue *vq, unsigned int head, int len)
 	/* Make sure buffer is written before we update index. */
 	wmb();
 	vq->vring.used->idx++;
+	vq->inflight--;
 }
 
 /* This actually sends the interrupt for this virtqueue */
@@ -726,8 +731,9 @@ static void trigger_irq(int fd, struct virtqueue *vq)
 {
 	unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
 
-	/* If they don't want an interrupt, don't send one. */
-	if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+	/* If they don't want an interrupt, don't send one, unless empty. */
+	if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+	    && vq->inflight)
 		return;
 
 	/* Send the Guest an interrupt tell them we used something up. */
@@ -1107,6 +1113,7 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
 	vq->next = NULL;
 	vq->last_avail_idx = 0;
 	vq->dev = dev;
+	vq->inflight = 0;
 
 	/* Initialize the configuration. */
 	vq->config.num = num_descs;
@@ -1368,6 +1375,7 @@ static void setup_tun_net(const char *arg)
 
 	/* Tell Guest what MAC address to use. */
 	add_feature(dev, VIRTIO_NET_F_MAC);
+	add_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY);
 	set_config(dev, sizeof(conf), &conf);
 
 	/* We don't need the socket any more; setup is done. */
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index af65b2da3ba0dabd19d0e14fcfbb52577ff4c96c..5c7e2fd52075be167680311b13d5e7c9d120bbe4 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -582,8 +582,9 @@ static void __init lguest_init_IRQ(void)
 		int vector = FIRST_EXTERNAL_VECTOR + i;
 		if (vector != SYSCALL_VECTOR) {
 			set_intr_gate(vector, interrupt[i]);
-			set_irq_chip_and_handler(i, &lguest_irq_controller,
-						 handle_level_irq);
+			set_irq_chip_and_handler_name(i, &lguest_irq_controller,
+						      handle_level_irq,
+						      "level");
 		}
 	}
 	/* This call is required to set up for 4k stacks, where we have
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 84e064ffee5229e73d2f9f45af19a3ec581f5315..dd7ea203f940dc664a9ac74ef9fa157ac3a36b5b 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -260,6 +260,10 @@ static int virtblk_probe(struct virtio_device *vdev)
 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
 		blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
 
+	/* If disk is read-only in the host, the guest should obey */
+	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
+		set_disk_ro(vblk->disk, 1);
+
 	/* Host must always specify the capacity. */
 	vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
 			  &cap, sizeof(cap));
@@ -311,6 +315,7 @@ static void virtblk_remove(struct virtio_device *vdev)
 	/* Stop all the virtqueues. */
 	vdev->config->reset(vdev);
 
+	del_gendisk(vblk->disk);
 	blk_cleanup_queue(vblk->disk->queue);
 	put_disk(vblk->disk);
 	mempool_destroy(vblk->pool);
@@ -325,7 +330,7 @@ static struct virtio_device_id id_table[] = {
 
 static unsigned int features[] = {
 	VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
-	VIRTIO_BLK_F_GEOMETRY,
+	VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO,
 };
 
 static struct virtio_driver virtio_blk = {
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 8d6c2089d2a8480bf1829d0b3d24bca959b22a31..efd0b4db7c8ed6c5d6c6bbc5a473466f898fdf1d 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -112,3 +112,12 @@ config HW_RANDOM_PASEMI
 
 	  If unsure, say Y.
 
+config HW_RANDOM_VIRTIO
+	tristate "VirtIO Random Number Generator support"
+	depends on HW_RANDOM && VIRTIO
+	---help---
+	  This driver provides kernel-side support for the virtual Random Number
+	  Generator hardware.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called virtio-rng.  If unsure, say N.
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index c8b7300e2fb183f6ed6c6d1eb4f6ccfa358fb6bc..b4940ddbb35f5993c80c164dbea1a2046915d1dd 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_HW_RANDOM_VIA) += via-rng.o
 obj-$(CONFIG_HW_RANDOM_IXP4XX) += ixp4xx-rng.o
 obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o
 obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o
+obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
new file mode 100644
index 0000000000000000000000000000000000000000..d0e563e4fc399bf37f06a4d19cea0bfcb5017713
--- /dev/null
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -0,0 +1,155 @@
+/*
+ * Randomness driver for virtio
+ *  Copyright (C) 2007, 2008 Rusty Russell IBM Corporation
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+#include <linux/err.h>
+#include <linux/hw_random.h>
+#include <linux/scatterlist.h>
+#include <linux/spinlock.h>
+#include <linux/virtio.h>
+#include <linux/virtio_rng.h>
+
+/* The host will fill any buffer we give it with sweet, sweet randomness.  We
+ * give it 64 bytes at a time, and the hwrng framework takes it 4 bytes at a
+ * time. */
+#define RANDOM_DATA_SIZE 64
+
+static struct virtqueue *vq;
+static u32 *random_data;
+static unsigned int data_left;
+static DECLARE_COMPLETION(have_data);
+
+static void random_recv_done(struct virtqueue *vq)
+{
+	int len;
+
+	/* We never get spurious callbacks. */
+	if (!vq->vq_ops->get_buf(vq, &len))
+		BUG();
+
+	data_left = len / sizeof(random_data[0]);
+	complete(&have_data);
+}
+
+static void register_buffer(void)
+{
+	struct scatterlist sg;
+
+	sg_init_one(&sg, random_data, RANDOM_DATA_SIZE);
+	/* There should always be room for one buffer. */
+	if (vq->vq_ops->add_buf(vq, &sg, 0, 1, random_data) != 0)
+		BUG();
+	vq->vq_ops->kick(vq);
+}
+
+/* At least we don't udelay() in a loop like some other drivers. */
+static int virtio_data_present(struct hwrng *rng, int wait)
+{
+	if (data_left)
+		return 1;
+
+	if (!wait)
+		return 0;
+
+	wait_for_completion(&have_data);
+	return 1;
+}
+
+/* virtio_data_present() must have succeeded before this is called. */
+static int virtio_data_read(struct hwrng *rng, u32 *data)
+{
+	BUG_ON(!data_left);
+
+	*data = random_data[--data_left];
+
+	if (!data_left) {
+		init_completion(&have_data);
+		register_buffer();
+	}
+	return sizeof(*data);
+}
+
+static struct hwrng virtio_hwrng = {
+	.name = "virtio",
+	.data_present = virtio_data_present,
+	.data_read = virtio_data_read,
+};
+
+static int virtrng_probe(struct virtio_device *vdev)
+{
+	int err;
+
+	/* We expect a single virtqueue. */
+	vq = vdev->config->find_vq(vdev, 0, random_recv_done);
+	if (IS_ERR(vq))
+		return PTR_ERR(vq);
+
+	err = hwrng_register(&virtio_hwrng);
+	if (err) {
+		vdev->config->del_vq(vq);
+		return err;
+	}
+
+	register_buffer();
+	return 0;
+}
+
+static void virtrng_remove(struct virtio_device *vdev)
+{
+	vdev->config->reset(vdev);
+	hwrng_unregister(&virtio_hwrng);
+	vdev->config->del_vq(vq);
+}
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_RNG, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct virtio_driver virtio_rng = {
+	.driver.name =	KBUILD_MODNAME,
+	.driver.owner =	THIS_MODULE,
+	.id_table =	id_table,
+	.probe =	virtrng_probe,
+	.remove =	__devexit_p(virtrng_remove),
+};
+
+static int __init init(void)
+{
+	int err;
+
+	random_data = kmalloc(RANDOM_DATA_SIZE, GFP_KERNEL);
+	if (!random_data)
+		return -ENOMEM;
+
+	err = register_virtio_driver(&virtio_rng);
+	if (err)
+		kfree(random_data);
+	return err;
+}
+
+static void __exit fini(void)
+{
+	kfree(random_data);
+	unregister_virtio_driver(&virtio_rng);
+}
+module_init(init);
+module_exit(fini);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio random number driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index 8080249957afb6d747631674d32cdc287319f96c..1a8de57289eb97e5877b9016855cfe9e99adaac1 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -20,14 +20,11 @@
 /* The pointer to our (page) of device descriptions. */
 static void *lguest_devices;
 
-/* Unique numbering for lguest devices. */
-static unsigned int dev_index;
-
 /* For Guests, device memory can be used as normal memory, so we cast away the
  * __iomem to quieten sparse. */
 static inline void *lguest_map(unsigned long phys_addr, unsigned long pages)
 {
-	return (__force void *)ioremap(phys_addr, PAGE_SIZE*pages);
+	return (__force void *)ioremap_cache(phys_addr, PAGE_SIZE*pages);
 }
 
 static inline void lguest_unmap(void *addr)
@@ -325,8 +322,10 @@ static struct device lguest_root = {
  * As Andrew Tridgell says, "Untested code is buggy code".
  *
  * It's worth reading this carefully: we start with a pointer to the new device
- * descriptor in the "lguest_devices" page. */
-static void add_lguest_device(struct lguest_device_desc *d)
+ * descriptor in the "lguest_devices" page, and the offset into the device
+ * descriptor page so we can uniquely identify it if things go badly wrong. */
+static void add_lguest_device(struct lguest_device_desc *d,
+			      unsigned int offset)
 {
 	struct lguest_device *ldev;
 
@@ -334,18 +333,14 @@ static void add_lguest_device(struct lguest_device_desc *d)
 	 * it. */
 	ldev = kzalloc(sizeof(*ldev), GFP_KERNEL);
 	if (!ldev) {
-		printk(KERN_EMERG "Cannot allocate lguest dev %u\n",
-		       dev_index++);
+		printk(KERN_EMERG "Cannot allocate lguest dev %u type %u\n",
+		       offset, d->type);
 		return;
 	}
 
 	/* This devices' parent is the lguest/ dir. */
 	ldev->vdev.dev.parent = &lguest_root;
 	/* We have a unique device index thanks to the dev_index counter. */
-	ldev->vdev.index = dev_index++;
-	/* The device type comes straight from the descriptor.  There's also a
-	 * device vendor field in the virtio_device struct, which we leave as
-	 * 0. */
 	ldev->vdev.id.device = d->type;
 	/* We have a simple set of routines for querying the device's
 	 * configuration information and setting its status. */
@@ -357,8 +352,8 @@ static void add_lguest_device(struct lguest_device_desc *d)
 	 * virtio_device and calls device_register().  This makes the bus
 	 * infrastructure look for a matching driver. */
 	if (register_virtio_device(&ldev->vdev) != 0) {
-		printk(KERN_ERR "Failed to register lguest device %u\n",
-		       ldev->vdev.index);
+		printk(KERN_ERR "Failed to register lguest dev %u type %u\n",
+		       offset, d->type);
 		kfree(ldev);
 	}
 }
@@ -379,7 +374,7 @@ static void scan_devices(void)
 			break;
 
 		printk("Device at %i has size %u\n", i, desc_size(d));
-		add_lguest_device(d);
+		add_lguest_device(d, i);
 	}
 }
 
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 9f55ce6f3c7817380f87a429ae74d0f071fa3047..5ab34340919be3a417caf1ad5bfd50ff91f1054d 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -31,11 +31,6 @@
  */
 static void *kvm_devices;
 
-/*
- * Unique numbering for kvm devices.
- */
-static unsigned int dev_index;
-
 struct kvm_device {
 	struct virtio_device vdev;
 	struct kvm_device_desc *desc;
@@ -250,26 +245,25 @@ static struct device kvm_root = {
  * adds a new device and register it with virtio
  * appropriate drivers are loaded by the device model
  */
-static void add_kvm_device(struct kvm_device_desc *d)
+static void add_kvm_device(struct kvm_device_desc *d, unsigned int offset)
 {
 	struct kvm_device *kdev;
 
 	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
 	if (!kdev) {
-		printk(KERN_EMERG "Cannot allocate kvm dev %u\n",
-		       dev_index++);
+		printk(KERN_EMERG "Cannot allocate kvm dev %u type %u\n",
+		       offset, d->type);
 		return;
 	}
 
 	kdev->vdev.dev.parent = &kvm_root;
-	kdev->vdev.index = dev_index++;
 	kdev->vdev.id.device = d->type;
 	kdev->vdev.config = &kvm_vq_configspace_ops;
 	kdev->desc = d;
 
 	if (register_virtio_device(&kdev->vdev) != 0) {
-		printk(KERN_ERR "Failed to register kvm device %u\n",
-		       kdev->vdev.index);
+		printk(KERN_ERR "Failed to register kvm device %u type %u\n",
+		       offset, d->type);
 		kfree(kdev);
 	}
 }
@@ -289,7 +283,7 @@ static void scan_devices(void)
 		if (d->type == 0)
 			break;
 
-		add_kvm_device(d);
+		add_kvm_device(d, i);
 	}
 }
 
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 13866789b3561027b803797a95c985f573671fd4..0f3c2bb7bf3523ef2987788389c640748f516b39 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -2,6 +2,9 @@
 #include <linux/spinlock.h>
 #include <linux/virtio_config.h>
 
+/* Unique numbering for virtio devices. */
+static unsigned int dev_index;
+
 static ssize_t device_show(struct device *_d,
 			   struct device_attribute *attr, char *buf)
 {
@@ -166,7 +169,10 @@ int register_virtio_device(struct virtio_device *dev)
 	int err;
 
 	dev->dev.bus = &virtio_bus;
-	sprintf(dev->dev.bus_id, "%u", dev->index);
+
+	/* Assign a unique device index and hence name. */
+	dev->index = dev_index++;
+	sprintf(dev->dev.bus_id, "virtio%u", dev->index);
 
 	/* We always start by resetting the device, in case a previous
 	 * driver messed it up.  This also tests that code path a little. */
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 27e9fc9117cdfa69fee88e32e3636a844d803d5e..eae7236310e450ce1647a25a480eccad9147dec4 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -78,9 +78,6 @@ static struct device virtio_pci_root = {
 	.bus_id		= "virtio-pci",
 };
 
-/* Unique numbering for devices under the kvm root */
-static unsigned int dev_index;
-
 /* Convert a generic virtio device to our structure */
 static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
 {
@@ -325,10 +322,6 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
 	if (vp_dev == NULL)
 		return -ENOMEM;
 
-	snprintf(vp_dev->vdev.dev.bus_id, BUS_ID_SIZE, "virtio%d", dev_index);
-	vp_dev->vdev.index = dev_index;
-	dev_index++;
-
 	vp_dev->vdev.dev.parent = &virtio_pci_root;
 	vp_dev->vdev.config = &virtio_pci_config_ops;
 	vp_dev->pci_dev = pci_dev;
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 937a49d6772cc5271d22ef48cb14df6bf56c07f7..72bf8bc090142f02a9065c0ff0448299a5e9a2e7 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -227,7 +227,6 @@ static bool vring_enable_cb(struct virtqueue *_vq)
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
 	START_USE(vq);
-	BUG_ON(!(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT));
 
 	/* We optimistically turn back on interrupts, then check if there was
 	 * more to do. */
@@ -254,13 +253,6 @@ irqreturn_t vring_interrupt(int irq, void *_vq)
 	if (unlikely(vq->broken))
 		return IRQ_HANDLED;
 
-	/* Other side may have missed us turning off the interrupt,
-	 * but we should preserve disable semantic for virtio users. */
-	if (unlikely(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {
-		pr_debug("virtqueue interrupt after disable for %p\n", vq);
-		return IRQ_HANDLED;
-	}
-
 	pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback);
 	if (vq->vq.callback)
 		vq->vq.callback(&vq->vq);
diff --git a/include/linux/virtio_blk.h b/include/linux/virtio_blk.h
index d4695a3356d018f4198df0d5813070cc4b5cf5ad..5f79a5f9de796b297c86f2647acfce713a533826 100644
--- a/include/linux/virtio_blk.h
+++ b/include/linux/virtio_blk.h
@@ -10,18 +10,19 @@
 #define VIRTIO_BLK_F_SIZE_MAX	1	/* Indicates maximum segment size */
 #define VIRTIO_BLK_F_SEG_MAX	2	/* Indicates maximum # of segments */
 #define VIRTIO_BLK_F_GEOMETRY	4	/* Legacy geometry available  */
+#define VIRTIO_BLK_F_RO		5	/* Disk is read-only */
 
 struct virtio_blk_config
 {
 	/* The capacity (in 512-byte sectors). */
-	__le64 capacity;
+	__u64 capacity;
 	/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
-	__le32 size_max;
+	__u32 size_max;
 	/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
-	__le32 seg_max;
+	__u32 seg_max;
 	/* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
 	struct virtio_blk_geometry {
-		__le16 cylinders;
+		__u16 cylinders;
 		__u8 heads;
 		__u8 sectors;
 	} geometry;
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 50db245c81ad94f1131d88b512c100219475717b..f364bbf63c3413547738ae4028b399577bc76650 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -15,6 +15,10 @@
 /* We've given up on this device. */
 #define VIRTIO_CONFIG_S_FAILED		0x80
 
+/* Do we get callbacks when the ring is completely used, even if we've
+ * suppressed them? */
+#define VIRTIO_F_NOTIFY_ON_EMPTY	24
+
 #ifdef __KERNEL__
 #include <linux/virtio.h>
 
@@ -99,7 +103,7 @@ static inline bool virtio_has_feature(const struct virtio_device *vdev,
  * The return value is -ENOENT if the feature doesn't exist.  Otherwise
  * the config value is copied into whatever is pointed to by v. */
 #define virtio_config_val(vdev, fbit, offset, v) \
-	virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(v))
+	virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
 
 static inline int virtio_config_buf(struct virtio_device *vdev,
 				    unsigned int fbit,
diff --git a/include/linux/virtio_rng.h b/include/linux/virtio_rng.h
new file mode 100644
index 0000000000000000000000000000000000000000..331afb6c9f6282a21b9efb7972a161563122974e
--- /dev/null
+++ b/include/linux/virtio_rng.h
@@ -0,0 +1,8 @@
+#ifndef _LINUX_VIRTIO_RNG_H
+#define _LINUX_VIRTIO_RNG_H
+#include <linux/virtio_config.h>
+
+/* The ID for virtio_rng */
+#define VIRTIO_ID_RNG	4
+
+#endif /* _LINUX_VIRTIO_RNG_H */