Merge tag 'drm/tegra/for-5.1-rc5' of git://anongit.freedesktop.org/tegra/linux into...

[thirdparty/kernel/stable.git] / drivers / vfio / vfio_iommu_type1.c

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 73652e21efec6a28393bd979d2d42caef711b280..d0f731c9920a65a44d614181ecf3a4e4c2d90755 100644 (file)
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -58,12 +58,18 @@ module_param_named(disable_hugepages,
 MODULE_PARM_DESC(disable_hugepages,
                 "Disable VFIO IOMMU support for IOMMU hugepages.");
 
+static unsigned int dma_entry_limit __read_mostly = U16_MAX;
+module_param_named(dma_entry_limit, dma_entry_limit, uint, 0644);
+MODULE_PARM_DESC(dma_entry_limit,
+                "Maximum number of user DMA mappings per container (65535).");
+
 struct vfio_iommu {
        struct list_head        domain_list;
        struct vfio_domain      *external_domain; /* domain for external user */
        struct mutex            lock;
        struct rb_root          dma_list;
        struct blocking_notifier_head notifier;
+       unsigned int            dma_avail;
        bool                    v2;
        bool                    nesting;
 };
@@ -836,6 +842,7 @@ static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
        vfio_unlink_dma(iommu, dma);
        put_task_struct(dma->task);
        kfree(dma);
+       iommu->dma_avail++;
 }
 
 static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu)
@@ -1081,12 +1088,18 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
                goto out_unlock;
        }
 
+       if (!iommu->dma_avail) {
+               ret = -ENOSPC;
+               goto out_unlock;
+       }
+
        dma = kzalloc(sizeof(*dma), GFP_KERNEL);
        if (!dma) {
                ret = -ENOMEM;
                goto out_unlock;
        }
 
+       iommu->dma_avail--;
        dma->iova = iova;
        dma->vaddr = vaddr;
        dma->prot = prot;
@@ -1583,6 +1596,7 @@ static void *vfio_iommu_type1_open(unsigned long arg)
 
        INIT_LIST_HEAD(&iommu->domain_list);
        iommu->dma_list = RB_ROOT;
+       iommu->dma_avail = dma_entry_limit;
        mutex_init(&iommu->lock);
        BLOCKING_INIT_NOTIFIER_HEAD(&iommu->notifier);