[PATCH 2/3 V3] kvm tools: Prevent PFN wraparound

[PATCH 2/3 V3] kvm tools: Prevent PFN wraparound

[levinsasha928]

From: Sasha Levin <levinsasha928@gmail.com>

queue->pfn may be used to point at addresses larger
than 32 bit.
Prevent a wraparound when shifting it left.

Changes in V2:
 - Use helper function.

Changes in V3:
 - Add warning for using guest_pfn_to_host() on 32-bit hosts.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/include/kvm/virtio.h |   10 ++++++++++
 tools/kvm/virtio/blk.c         |    2 +-
 tools/kvm/virtio/console.c     |    2 +-
 tools/kvm/virtio/net.c         |    2 +-
 tools/kvm/virtio/rng.c         |    2 +-
 5 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/tools/kvm/include/kvm/virtio.h b/tools/kvm/include/kvm/virtio.h
index 7f92dea..bea63df 100644
--- a/tools/kvm/include/kvm/virtio.h
+++ b/tools/kvm/include/kvm/virtio.h
@@ -36,6 +36,16 @@ static inline bool virt_queue__available(struct virt_queue *vq)
 	return vq->vring.avail->idx !=  vq->last_avail_idx;
 }
 
+/*
+ * Warning: on 32-bit hosts, shifting pfn left may cause a truncation of pfn values
+ * higher than 4GB - thus, pointing to the wrong area in guest virtual memory space
+ * and breaking the virt queue which owns this pfn.
+ */
+static inline void *guest_pfn_to_host(struct kvm *kvm, u32 pfn)
+{
+	return guest_flat_to_host(kvm, (unsigned long)pfn << 12);
+}
+
 struct vring_used_elem *virt_queue__set_used_elem(struct virt_queue *queue, u32 head, u32 len);
 
 u16 virt_queue__get_iov(struct virt_queue *queue, struct iovec iov[], u16 *out, u16 *in, struct kvm *kvm);
diff --git a/tools/kvm/virtio/blk.c b/tools/kvm/virtio/blk.c
index 12c7029..9f1aa1d 100644
--- a/tools/kvm/virtio/blk.c
+++ b/tools/kvm/virtio/blk.c
@@ -197,7 +197,7 @@ static bool virtio_blk_pci_io_out(struct kvm *self, u16 port, void *data, int si
 
 		queue			= &bdev->vqs[bdev->queue_selector];
 		queue->pfn		= ioport__read32(data);
-		p			= guest_flat_to_host(self, queue->pfn << 12);
+		p			= guest_pfn_to_host(self, queue->pfn);
 
 		vring_init(&queue->vring, VIRTIO_BLK_QUEUE_SIZE, p, 4096);
 
diff --git a/tools/kvm/virtio/console.c b/tools/kvm/virtio/console.c
index f9031cb..87b816a 100644
--- a/tools/kvm/virtio/console.c
+++ b/tools/kvm/virtio/console.c
@@ -199,7 +199,7 @@ static bool virtio_console_pci_io_out(struct kvm *self, u16 port, void *data, in
 
 		queue			= &cdev.vqs[cdev.queue_selector];
 		queue->pfn		= ioport__read32(data);
-		p			= guest_flat_to_host(self, queue->pfn << 12);
+		p			= guest_pfn_to_host(self, queue->pfn);
 
 		vring_init(&queue->vring, VIRTIO_CONSOLE_QUEUE_SIZE, p, 4096);
 
diff --git a/tools/kvm/virtio/net.c b/tools/kvm/virtio/net.c
index 8d430e3..3f3ee22 100644
--- a/tools/kvm/virtio/net.c
+++ b/tools/kvm/virtio/net.c
@@ -245,7 +245,7 @@ static bool virtio_net_pci_io_out(struct kvm *self, u16 port, void *data, int si
 
 		queue				= &net_device.vqs[net_device.queue_selector];
 		queue->pfn			= ioport__read32(data);
-		p				= guest_flat_to_host(self, queue->pfn << 12);
+		p				= guest_pfn_to_host(self, queue->pfn);
 
 		vring_init(&queue->vring, VIRTIO_NET_QUEUE_SIZE, p, 4096);
 
diff --git a/tools/kvm/virtio/rng.c b/tools/kvm/virtio/rng.c
index f692dfd..1951d0d1c 100644
--- a/tools/kvm/virtio/rng.c
+++ b/tools/kvm/virtio/rng.c
@@ -129,7 +129,7 @@ static bool virtio_rng_pci_io_out(struct kvm *kvm, u16 port, void *data, int siz
 
 		queue			= &rdev.vqs[rdev.queue_selector];
 		queue->pfn		= ioport__read32(data);
-		p			= guest_flat_to_host(kvm, queue->pfn << 12);
+		p			= guest_pfn_to_host(kvm, queue->pfn);
 
 		vring_init(&queue->vring, VIRTIO_RNG_QUEUE_SIZE, p, 4096);
 
-- 
1.7.5.rc3

[PATCH 3/3] kvm tools: Use definitions from kernel headers

[levinsasha928]

From: Sasha Levin <levinsasha928@gmail.com>

Instead of redefining virtio pci constants (or
not using them at all), use constants from kernel
header.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/include/kvm/virtio-pci-dev.h |    3 +
 tools/kvm/include/kvm/virtio-pci.h     |   74 --------------------------------
 tools/kvm/include/kvm/virtio.h         |    3 +-
 tools/kvm/virtio/blk.c                 |    5 +-
 tools/kvm/virtio/console.c             |    9 ++--
 tools/kvm/virtio/net.c                 |    9 ++--
 tools/kvm/virtio/rng.c                 |    3 +-
 7 files changed, 16 insertions(+), 90 deletions(-)
 delete mode 100644 tools/kvm/include/kvm/virtio-pci.h

diff --git a/tools/kvm/include/kvm/virtio-pci-dev.h b/tools/kvm/include/kvm/virtio-pci-dev.h
index d2274d0..706ad20 100644
--- a/tools/kvm/include/kvm/virtio-pci-dev.h
+++ b/tools/kvm/include/kvm/virtio-pci-dev.h
@@ -16,4 +16,7 @@
 #define PCI_SUBSYSTEM_ID_VIRTIO_CONSOLE		0x0003
 #define PCI_SUBSYSTEM_ID_VIRTIO_RNG		0x0004
 
+#define PCI_VENDOR_ID_REDHAT_QUMRANET		0x1af4
+#define PCI_SUBSYSTEM_VENDOR_ID_REDHAT_QUMRANET	0x1af4
+
 #endif /* VIRTIO_PCI_DEV_H_ */
diff --git a/tools/kvm/include/kvm/virtio-pci.h b/tools/kvm/include/kvm/virtio-pci.h
deleted file mode 100644
index b507d1d..0000000
--- a/tools/kvm/include/kvm/virtio-pci.h
+++ /dev/null
@@ -1,74 +0,0 @@
-/*
- * Virtio PCI driver
- *
- * This module allows virtio devices to be used over a virtual PCI device.
- * This can be used with QEMU based VMMs like KVM or Xen.
- *
- * Copyright IBM Corp. 2007
- *
- * Authors:
- *  Anthony Liguori  <aliguori@us.ibm.com>
- *
- * This header is BSD licensed so anyone can use the definitions to implement
- * compatible drivers/servers.
- */
-
-#ifndef _LINUX_VIRTIO_PCI_H
-#define _LINUX_VIRTIO_PCI_H
-
-/* A 32-bit r/o bitmask of the features supported by the host */
-#define VIRTIO_PCI_HOST_FEATURES	0
-
-/* A 32-bit r/w bitmask of features activated by the guest */
-#define VIRTIO_PCI_GUEST_FEATURES	4
-
-/* A 32-bit r/w PFN for the currently selected queue */
-#define VIRTIO_PCI_QUEUE_PFN		8
-
-/* A 16-bit r/o queue size for the currently selected queue */
-#define VIRTIO_PCI_QUEUE_NUM		12
-
-/* A 16-bit r/w queue selector */
-#define VIRTIO_PCI_QUEUE_SEL		14
-
-/* A 16-bit r/w queue notifier */
-#define VIRTIO_PCI_QUEUE_NOTIFY		16
-
-/* An 8-bit device status register */
-#define VIRTIO_PCI_STATUS		18
-
-/*
- * An 8-bit r/o interrupt status register.
- *
- * Reading the value will return the current contents of
- * the ISR and will also clear it. This is effectively
- * a read-and-acknowledge.
- */
-#define VIRTIO_PCI_ISR			19
-
-/*
- * MSI-X registers: only enabled if MSI-X is enabled.
- */
-
-/* A 16-bit vector for configuration changes */
-#define VIRTIO_MSI_CONFIG_VECTOR        20
-
-/* A 16-bit vector for selected queue notifications */
-#define VIRTIO_MSI_QUEUE_VECTOR         22
-
-/* Vector value used to disable MSI for queue */
-#define VIRTIO_MSI_NO_VECTOR            0xffff
-
-/*
- * Config space size.
- */
-#define VIRTIO_PCI_CONFIG_NOMSI         20
-#define VIRTIO_PCI_CONFIG_MSI           24
-
-/*
- * Virtio config space constants.
- */
-#define PCI_VENDOR_ID_REDHAT_QUMRANET		0x1af4
-#define PCI_SUBSYSTEM_VENDOR_ID_REDHAT_QUMRANET	0x1af4
-
-#endif /* _LINUX_VIRTIO_PCI_H */
diff --git a/tools/kvm/include/kvm/virtio.h b/tools/kvm/include/kvm/virtio.h
index bea63df..66e6fdb 100644
--- a/tools/kvm/include/kvm/virtio.h
+++ b/tools/kvm/include/kvm/virtio.h
@@ -2,6 +2,7 @@
 #define KVM__VIRTIO_H
 
 #include <linux/virtio_ring.h>
+#include <linux/virtio_pci.h>
 
 #include <linux/types.h>
 #include <sys/uio.h>
@@ -43,7 +44,7 @@ static inline bool virt_queue__available(struct virt_queue *vq)
  */
 static inline void *guest_pfn_to_host(struct kvm *kvm, u32 pfn)
 {
-	return guest_flat_to_host(kvm, (unsigned long)pfn << 12);
+	return guest_flat_to_host(kvm, (unsigned long)pfn << VIRTIO_PCI_QUEUE_ADDR_SHIFT);
 }
 
 struct vring_used_elem *virt_queue__set_used_elem(struct virt_queue *queue, u32 head, u32 len);
diff --git a/tools/kvm/virtio/blk.c b/tools/kvm/virtio/blk.c
index 9f1aa1d..8d480bf 100644
--- a/tools/kvm/virtio/blk.c
+++ b/tools/kvm/virtio/blk.c
@@ -1,6 +1,5 @@
 #include "kvm/virtio-blk.h"
 
-#include "kvm/virtio-pci.h"
 #include "kvm/virtio-pci-dev.h"
 #include "kvm/irq.h"
 #include "kvm/disk-image.h"
@@ -58,7 +57,7 @@ static bool virtio_blk_dev_in(struct blk_dev *bdev, void *data, unsigned long of
 	if (size != 1 || count != 1)
 		return false;
 
-	ioport__write8(data, config_space[offset - VIRTIO_PCI_CONFIG_NOMSI]);
+	ioport__write8(data, config_space[offset - VIRTIO_MSI_CONFIG_VECTOR]);
 
 	return true;
 }
@@ -199,7 +198,7 @@ static bool virtio_blk_pci_io_out(struct kvm *self, u16 port, void *data, int si
 		queue->pfn		= ioport__read32(data);
 		p			= guest_pfn_to_host(self, queue->pfn);
 
-		vring_init(&queue->vring, VIRTIO_BLK_QUEUE_SIZE, p, 4096);
+		vring_init(&queue->vring, VIRTIO_BLK_QUEUE_SIZE, p, VIRTIO_PCI_VRING_ALIGN);
 
 		*job			= (struct blk_dev_job) {
 			.vq			= queue,
diff --git a/tools/kvm/virtio/console.c b/tools/kvm/virtio/console.c
index 87b816a..38f52f9 100644
--- a/tools/kvm/virtio/console.c
+++ b/tools/kvm/virtio/console.c
@@ -1,5 +1,4 @@
 #include "kvm/virtio-console.h"
-#include "kvm/virtio-pci.h"
 #include "kvm/virtio-pci-dev.h"
 #include "kvm/disk-image.h"
 #include "kvm/virtio.h"
@@ -104,10 +103,10 @@ static bool virtio_console_pci_io_device_specific_in(void *data, unsigned long o
 	if (size != 1 || count != 1)
 		return false;
 
-	if ((offset - VIRTIO_PCI_CONFIG_NOMSI) > sizeof(struct virtio_console_config))
-		error("config offset is too big: %li", offset - VIRTIO_PCI_CONFIG_NOMSI);
+	if ((offset - VIRTIO_MSI_CONFIG_VECTOR) > sizeof(struct virtio_console_config))
+		error("config offset is too big: %li", offset - VIRTIO_MSI_CONFIG_VECTOR);
 
-	ioport__write8(data, config_space[offset - VIRTIO_PCI_CONFIG_NOMSI]);
+	ioport__write8(data, config_space[offset - VIRTIO_MSI_CONFIG_VECTOR]);
 
 	return true;
 }
@@ -201,7 +200,7 @@ static bool virtio_console_pci_io_out(struct kvm *self, u16 port, void *data, in
 		queue->pfn		= ioport__read32(data);
 		p			= guest_pfn_to_host(self, queue->pfn);
 
-		vring_init(&queue->vring, VIRTIO_CONSOLE_QUEUE_SIZE, p, 4096);
+		vring_init(&queue->vring, VIRTIO_CONSOLE_QUEUE_SIZE, p, VIRTIO_PCI_VRING_ALIGN);
 
 		if (cdev.queue_selector == VIRTIO_CONSOLE_TX_QUEUE)
 			cdev.jobs[cdev.queue_selector] = thread_pool__add_job(self, virtio_console_handle_callback, queue);
diff --git a/tools/kvm/virtio/net.c b/tools/kvm/virtio/net.c
index 3f3ee22..2009d4a 100644
--- a/tools/kvm/virtio/net.c
+++ b/tools/kvm/virtio/net.c
@@ -1,5 +1,4 @@
 #include "kvm/virtio-net.h"
-#include "kvm/virtio-pci.h"
 #include "kvm/virtio-pci-dev.h"
 #include "kvm/virtio.h"
 #include "kvm/ioport.h"
@@ -154,10 +153,10 @@ static bool virtio_net_pci_io_device_specific_in(void *data, unsigned long offse
 	if (size != 1 || count != 1)
 		return false;
 
-	if ((offset - VIRTIO_PCI_CONFIG_NOMSI) > sizeof(struct virtio_net_config))
-		error("config offset is too big: %li", offset - VIRTIO_PCI_CONFIG_NOMSI);
+	if ((offset - VIRTIO_MSI_CONFIG_VECTOR) > sizeof(struct virtio_net_config))
+		error("config offset is too big: %li", offset - VIRTIO_MSI_CONFIG_VECTOR);
 
-	ioport__write8(data, config_space[offset - VIRTIO_PCI_CONFIG_NOMSI]);
+	ioport__write8(data, config_space[offset - VIRTIO_MSI_CONFIG_VECTOR]);
 
 	return true;
 }
@@ -247,7 +246,7 @@ static bool virtio_net_pci_io_out(struct kvm *self, u16 port, void *data, int si
 		queue->pfn			= ioport__read32(data);
 		p				= guest_pfn_to_host(self, queue->pfn);
 
-		vring_init(&queue->vring, VIRTIO_NET_QUEUE_SIZE, p, 4096);
+		vring_init(&queue->vring, VIRTIO_NET_QUEUE_SIZE, p, VIRTIO_PCI_VRING_ALIGN);
 
 		break;
 	}
diff --git a/tools/kvm/virtio/rng.c b/tools/kvm/virtio/rng.c
index 1951d0d1c..cf258fa 100644
--- a/tools/kvm/virtio/rng.c
+++ b/tools/kvm/virtio/rng.c
@@ -1,6 +1,5 @@
 #include "kvm/virtio-rng.h"
 
-#include "kvm/virtio-pci.h"
 #include "kvm/virtio-pci-dev.h"
 
 #include "kvm/disk-image.h"
@@ -131,7 +130,7 @@ static bool virtio_rng_pci_io_out(struct kvm *kvm, u16 port, void *data, int siz
 		queue->pfn		= ioport__read32(data);
 		p			= guest_pfn_to_host(kvm, queue->pfn);
 
-		vring_init(&queue->vring, VIRTIO_RNG_QUEUE_SIZE, p, 4096);
+		vring_init(&queue->vring, VIRTIO_RNG_QUEUE_SIZE, p, VIRTIO_PCI_VRING_ALIGN);
 
 		rdev.jobs[rdev.queue_selector] = thread_pool__add_job(kvm, virtio_rng_do_io, queue);
 
-- 
1.7.5.rc3