Commit 0ea9ee43 authored by Max Gurtovoy's avatar Max Gurtovoy Committed by Michael S. Tsirkin
Browse files

vdpasim: protect concurrent access to iommu iotlb 



Iommu iotlb can be accessed by different cores for performing IO using
multiple virt queues. Add a spinlock to synchronize iotlb accesses.

This could be easily reproduced when using more than 1 pktgen threads
to inject traffic to vdpa simulator.

Fixes: 2c53d0f6("vdpasim: vDPA device simulator")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20200731073822.13326-1-jasowang@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 6234f805

drivers/vdpa/vdpa_sim/vdpa_sim.c

+27 −4
Original line number Diff line number Diff line
@@ -71,6 +71,8 @@ struct vdpasim { 
	u32 status;

	u32 generation;

	u64 features;

	/* spinlock to synchronize iommu table */

	spinlock_t iommu_lock;

};



/* TODO: cross-endian support */
@@ -136,7 +138,9 @@ static void vdpasim_reset(struct vdpasim *vdpasim) 
	for (i = 0; i < VDPASIM_VQ_NUM; i++)

		vdpasim_vq_reset(&vdpasim->vqs[i]);



	spin_lock(&vdpasim->iommu_lock);

	vhost_iotlb_reset(vdpasim->iommu);

	spin_unlock(&vdpasim->iommu_lock);



	vdpasim->features = 0;

	vdpasim->status = 0;
@@ -254,8 +258,10 @@ static dma_addr_t vdpasim_map_page(struct device *dev, struct page *page, 
	/* For simplicity, use identical mapping to avoid e.g iova

	 * allocator.

	 */

	spin_lock(&vdpasim->iommu_lock);

	ret = vhost_iotlb_add_range(iommu, pa, pa + size - 1,

				    pa, dir_to_perm(dir));

	spin_unlock(&vdpasim->iommu_lock);

	if (ret)

		return DMA_MAPPING_ERROR;
@@ -269,8 +275,10 @@ static void vdpasim_unmap_page(struct device *dev, dma_addr_t dma_addr, 
	struct vdpasim *vdpasim = dev_to_sim(dev);

	struct vhost_iotlb *iommu = vdpasim->iommu;



	spin_lock(&vdpasim->iommu_lock);

	vhost_iotlb_del_range(iommu, (u64)dma_addr,

			      (u64)dma_addr + size - 1);

	spin_unlock(&vdpasim->iommu_lock);

}



static void *vdpasim_alloc_coherent(struct device *dev, size_t size,
@@ -282,9 +290,10 @@ static void *vdpasim_alloc_coherent(struct device *dev, size_t size, 
	void *addr = kmalloc(size, flag);

	int ret;



	if (!addr)

	spin_lock(&vdpasim->iommu_lock);

	if (!addr) {

		*dma_addr = DMA_MAPPING_ERROR;

	else {

	} else {

		u64 pa = virt_to_phys(addr);



		ret = vhost_iotlb_add_range(iommu, (u64)pa,
@@ -297,6 +306,7 @@ static void *vdpasim_alloc_coherent(struct device *dev, size_t size, 
		} else

			*dma_addr = (dma_addr_t)pa;

	}

	spin_unlock(&vdpasim->iommu_lock);



	return addr;

}
@@ -308,8 +318,11 @@ static void vdpasim_free_coherent(struct device *dev, size_t size, 
	struct vdpasim *vdpasim = dev_to_sim(dev);

	struct vhost_iotlb *iommu = vdpasim->iommu;



	spin_lock(&vdpasim->iommu_lock);

	vhost_iotlb_del_range(iommu, (u64)dma_addr,

			      (u64)dma_addr + size - 1);

	spin_unlock(&vdpasim->iommu_lock);



	kfree(phys_to_virt((uintptr_t)dma_addr));

}
@@ -555,6 +568,7 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, 
	u64 start = 0ULL, last = 0ULL - 1;

	int ret;



	spin_lock(&vdpasim->iommu_lock);

	vhost_iotlb_reset(vdpasim->iommu);



	for (map = vhost_iotlb_itree_first(iotlb, start, last); map;
@@ -564,10 +578,12 @@ static int vdpasim_set_map(struct vdpa_device *vdpa, 
		if (ret)

			goto err;

	}

	spin_unlock(&vdpasim->iommu_lock);

	return 0;



err:

	vhost_iotlb_reset(vdpasim->iommu);

	spin_unlock(&vdpasim->iommu_lock);

	return ret;

}
@@ -575,16 +591,23 @@ static int vdpasim_dma_map(struct vdpa_device *vdpa, u64 iova, u64 size, 
			   u64 pa, u32 perm)

{

	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);

	int ret;



	return vhost_iotlb_add_range(vdpasim->iommu, iova,

				     iova + size - 1, pa, perm);

	spin_lock(&vdpasim->iommu_lock);

	ret = vhost_iotlb_add_range(vdpasim->iommu, iova, iova + size - 1, pa,

				    perm);

	spin_unlock(&vdpasim->iommu_lock);



	return ret;

}



static int vdpasim_dma_unmap(struct vdpa_device *vdpa, u64 iova, u64 size)

{

	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);



	spin_lock(&vdpasim->iommu_lock);

	vhost_iotlb_del_range(vdpasim->iommu, iova, iova + size - 1);

	spin_unlock(&vdpasim->iommu_lock);



	return 0;

}

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