Commit 399f4dae authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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()
parents ddd7ad5c 76f40853

Documentation/driver-api/virtio/writing_virtio_drivers.rst

+0 −1
Original line number Diff line number Diff line
@@ -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,

drivers/vhost/vhost.c

+23 −3
Original line number Diff line number Diff line
@@ -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);

drivers/virtio/virtio.c

+4 −2
Original line number Diff line number Diff line
@@ -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)

{

include/linux/virtio.h

+5 −2
Original line number Diff line number Diff line
@@ -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

include/uapi/linux/vhost.h

+8 −7
Original line number Diff line number Diff line
@@ -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