Commit f53d9910 authored by Stefano Garzarella's avatar Stefano Garzarella Committed by Michael S. Tsirkin
Browse files

vringh: add 'iotlb_lock' to synchronize iotlb accesses 



Usually iotlb accesses are synchronized with a spinlock.
Let's request it as a new parameter in vringh_set_iotlb() and
hold it when we navigate the iotlb in iotlb_translate() to avoid
race conditions with any new additions/deletions of ranges from
the ioltb.

Acked-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20210315163450.254396-3-sgarzare@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 4080fc10

drivers/vdpa/vdpa_sim/vdpa_sim.c

+2 −1
Original line number Diff line number Diff line
@@ -284,7 +284,8 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr) 
		goto err_iommu;



	for (i = 0; i < dev_attr->nvqs; i++)

		vringh_set_iotlb(&vdpasim->vqs[i].vring, vdpasim->iommu);

		vringh_set_iotlb(&vdpasim->vqs[i].vring, vdpasim->iommu,

				 &vdpasim->iommu_lock);



	ret = iova_cache_get();

	if (ret)

drivers/vhost/vringh.c

+8 −1
Original line number Diff line number Diff line
@@ -1074,6 +1074,8 @@ static int iotlb_translate(const struct vringh *vrh, 
	int ret = 0;

	u64 s = 0;



	spin_lock(vrh->iotlb_lock);



	while (len > s) {

		u64 size, pa, pfn;
@@ -1103,6 +1105,8 @@ static int iotlb_translate(const struct vringh *vrh, 
		++ret;

	}



	spin_unlock(vrh->iotlb_lock);



	return ret;

}
@@ -1262,10 +1266,13 @@ EXPORT_SYMBOL(vringh_init_iotlb); 
 * vringh_set_iotlb - initialize a vringh for a ring with IOTLB.

 * @vrh: the vring

 * @iotlb: iotlb associated with this vring

 * @iotlb_lock: spinlock to synchronize the iotlb accesses

 */

void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb)

void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,

		      spinlock_t *iotlb_lock)

{

	vrh->iotlb = iotlb;

	vrh->iotlb_lock = iotlb_lock;

}

EXPORT_SYMBOL(vringh_set_iotlb);

include/linux/vringh.h

+5 −1
Original line number Diff line number Diff line
@@ -46,6 +46,9 @@ struct vringh { 
	/* IOTLB for this vring */

	struct vhost_iotlb *iotlb;



	/* spinlock to synchronize IOTLB accesses */

	spinlock_t *iotlb_lock;



	/* The function to call to notify the guest about added buffers */

	void (*notify)(struct vringh *);

};
@@ -258,7 +261,8 @@ static inline __virtio64 cpu_to_vringh64(const struct vringh *vrh, u64 val) 


#if IS_REACHABLE(CONFIG_VHOST_IOTLB)



void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb);

void vringh_set_iotlb(struct vringh *vrh, struct vhost_iotlb *iotlb,

		      spinlock_t *iotlb_lock);



int vringh_init_iotlb(struct vringh *vrh, u64 features,

		      unsigned int num, bool weak_barriers,