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authorLinus Torvalds <torvalds@linux-foundation.org>2024-04-14 10:05:59 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-04-14 10:05:59 -0700
commit399f4dae683a719eeeca8f30d3871577b53ffcca (patch)
tree0d07254a5ae9c90ff935de7f94915a08fb721154
parentddd7ad5cf1525b59c8231a6914156ebb09398cfd (diff)
parent76f408535aab39c33e0a1dcada9fba5631c65595 (diff)
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull virtio bugfixes from Michael Tsirkin: "Some small, obvious (in hindsight) bugfixes: - new ioctl in vhost-vdpa has a wrong # - not too late to fix - vhost has apparently been lacking an smp_rmb() - due to code duplication :( The duplication will be fixed in the next merge cycle, this is a minimal fix - an error message in vhost talks about guest moving used index - which of course never happens, guest only ever moves the available index - i2c-virtio didn't set the driver owner so it did not get refcounted correctly" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: vhost: correct misleading printing information vhost-vdpa: change ioctl # for VDPA_GET_VRING_SIZE virtio: store owner from modules with register_virtio_driver() vhost: Add smp_rmb() in vhost_enable_notify() vhost: Add smp_rmb() in vhost_vq_avail_empty()
-rw-r--r--Documentation/driver-api/virtio/writing_virtio_drivers.rst1
-rw-r--r--drivers/vhost/vhost.c26
-rw-r--r--drivers/virtio/virtio.c6
-rw-r--r--include/linux/virtio.h7
-rw-r--r--include/uapi/linux/vhost.h15
5 files changed, 40 insertions, 15 deletions
diff --git a/Documentation/driver-api/virtio/writing_virtio_drivers.rst b/Documentation/driver-api/virtio/writing_virtio_drivers.rst
index e14c58796d25..e5de6f5d061a 100644
--- a/Documentation/driver-api/virtio/writing_virtio_drivers.rst
+++ b/Documentation/driver-api/virtio/writing_virtio_drivers.rst
@@ -97,7 +97,6 @@ like this::
static struct virtio_driver virtio_dummy_driver = {
.driver.name = KBUILD_MODNAME,
- .driver.owner = THIS_MODULE,
.id_table = id_table,
.probe = virtio_dummy_probe,
.remove = virtio_dummy_remove,
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 045f666b4f12..8995730ce0bf 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2515,7 +2515,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
- vq_err(vq, "Guest moved used index from %u to %u",
+ vq_err(vq, "Guest moved avail index from %u to %u",
last_avail_idx, vq->avail_idx);
return -EFAULT;
}
@@ -2799,9 +2799,19 @@ bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
r = vhost_get_avail_idx(vq, &avail_idx);
if (unlikely(r))
return false;
+
vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
+ if (vq->avail_idx != vq->last_avail_idx) {
+ /* Since we have updated avail_idx, the following
+ * call to vhost_get_vq_desc() will read available
+ * ring entries. Make sure that read happens after
+ * the avail_idx read.
+ */
+ smp_rmb();
+ return false;
+ }
- return vq->avail_idx == vq->last_avail_idx;
+ return true;
}
EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
@@ -2838,9 +2848,19 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
&vq->avail->idx, r);
return false;
}
+
vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
+ if (vq->avail_idx != vq->last_avail_idx) {
+ /* Since we have updated avail_idx, the following
+ * call to vhost_get_vq_desc() will read available
+ * ring entries. Make sure that read happens after
+ * the avail_idx read.
+ */
+ smp_rmb();
+ return true;
+ }
- return vq->avail_idx != vq->last_avail_idx;
+ return false;
}
EXPORT_SYMBOL_GPL(vhost_enable_notify);
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index f173587893cb..9510c551dce8 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -362,14 +362,16 @@ static const struct bus_type virtio_bus = {
.remove = virtio_dev_remove,
};
-int register_virtio_driver(struct virtio_driver *driver)
+int __register_virtio_driver(struct virtio_driver *driver, struct module *owner)
{
/* Catch this early. */
BUG_ON(driver->feature_table_size && !driver->feature_table);
driver->driver.bus = &virtio_bus;
+ driver->driver.owner = owner;
+
return driver_register(&driver->driver);
}
-EXPORT_SYMBOL_GPL(register_virtio_driver);
+EXPORT_SYMBOL_GPL(__register_virtio_driver);
void unregister_virtio_driver(struct virtio_driver *driver)
{
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index b0201747a263..26c4325aa373 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -170,7 +170,7 @@ size_t virtio_max_dma_size(const struct virtio_device *vdev);
/**
* struct virtio_driver - operations for a virtio I/O driver
- * @driver: underlying device driver (populate name and owner).
+ * @driver: underlying device driver (populate name).
* @id_table: the ids serviced by this driver.
* @feature_table: an array of feature numbers supported by this driver.
* @feature_table_size: number of entries in the feature table array.
@@ -208,7 +208,10 @@ static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
return container_of(drv, struct virtio_driver, driver);
}
-int register_virtio_driver(struct virtio_driver *drv);
+/* use a macro to avoid include chaining to get THIS_MODULE */
+#define register_virtio_driver(drv) \
+ __register_virtio_driver(drv, THIS_MODULE)
+int __register_virtio_driver(struct virtio_driver *drv, struct module *owner);
void unregister_virtio_driver(struct virtio_driver *drv);
/* module_virtio_driver() - Helper macro for drivers that don't do
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index bea697390613..b95dd84eef2d 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -179,12 +179,6 @@
/* Get the config size */
#define VHOST_VDPA_GET_CONFIG_SIZE _IOR(VHOST_VIRTIO, 0x79, __u32)
-/* Get the count of all virtqueues */
-#define VHOST_VDPA_GET_VQS_COUNT _IOR(VHOST_VIRTIO, 0x80, __u32)
-
-/* Get the number of virtqueue groups. */
-#define VHOST_VDPA_GET_GROUP_NUM _IOR(VHOST_VIRTIO, 0x81, __u32)
-
/* Get the number of address spaces. */
#define VHOST_VDPA_GET_AS_NUM _IOR(VHOST_VIRTIO, 0x7A, unsigned int)
@@ -228,10 +222,17 @@
#define VHOST_VDPA_GET_VRING_DESC_GROUP _IOWR(VHOST_VIRTIO, 0x7F, \
struct vhost_vring_state)
+
+/* Get the count of all virtqueues */
+#define VHOST_VDPA_GET_VQS_COUNT _IOR(VHOST_VIRTIO, 0x80, __u32)
+
+/* Get the number of virtqueue groups. */
+#define VHOST_VDPA_GET_GROUP_NUM _IOR(VHOST_VIRTIO, 0x81, __u32)
+
/* Get the queue size of a specific virtqueue.
* userspace set the vring index in vhost_vring_state.index
* kernel set the queue size in vhost_vring_state.num
*/
-#define VHOST_VDPA_GET_VRING_SIZE _IOWR(VHOST_VIRTIO, 0x80, \
+#define VHOST_VDPA_GET_VRING_SIZE _IOWR(VHOST_VIRTIO, 0x82, \
struct vhost_vring_state)
#endif