+ */
+#include <linux/dma-buf.h>
+#include <linux/pci-p2pdma.h>
+#include <linux/dma-resv.h>
+
+#include "vfio_pci_priv.h"
+
+MODULE_IMPORT_NS(DMA_BUF);
+
+struct vfio_pci_dma_buf {
+ struct dma_buf *dmabuf;
+ struct vfio_pci_core_device *vdev;
+ struct list_head dmabufs_elm;
+ struct page **pages;
+ struct sg_table *sg;
+ unsigned int nr_pages;
+ bool revoked;
+};
+
+static vm_fault_t vfio_pci_dma_buf_fault(struct vm_fault *vmf)
+{
+ struct vm_area_struct *vma = vmf->vma;
+ struct vfio_pci_dma_buf *priv = vma->vm_private_data;
+ pgoff_t pgoff = vmf->pgoff;
+
+ if (pgoff >= priv->nr_pages)
+ return VM_FAULT_SIGBUS;
+
+ return vmf_insert_pfn(vma, vmf->address,
+ page_to_pfn(priv->pages[pgoff]));
+}
+
+static const struct vm_operations_struct vfio_pci_dma_buf_vmops = {
+ .fault = vfio_pci_dma_buf_fault,
+};
+
+static int vfio_pci_dma_buf_mmap(struct dma_buf *dmabuf,
+ struct vm_area_struct *vma)
+{
+ struct vfio_pci_dma_buf *priv = dmabuf->priv;
+
+ if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
+ return -EINVAL;
+
+ vma->vm_ops = &vfio_pci_dma_buf_vmops;
+ vma->vm_private_data = priv;
+ vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
+ return 0;
+}
+
+static int vfio_pci_dma_buf_attach(struct dma_buf *dmabuf,
+ struct dma_buf_attachment *attachment)
+{
+ struct vfio_pci_dma_buf *priv = dmabuf->priv;
+ int rc;
+
+ rc = pci_p2pdma_distance_many(priv->vdev->pdev, &attachment->dev, 1,
+ true);
+ if (rc < 0)
+ attachment->peer2peer = false;
+ return 0;
+}
+
+static void vfio_pci_dma_buf_unpin(struct dma_buf_attachment *attachment)
+{
+}
+
+static int vfio_pci_dma_buf_pin(struct dma_buf_attachment *attachment)
+{
+ /*
+ * Uses the dynamic interface but must always allow for
+ * dma_buf_move_notify() to do revoke
+ */
+ return -EINVAL;
+}
+
+static struct sg_table *
+vfio_pci_dma_buf_map(struct dma_buf_attachment *attachment,
+ enum dma_data_direction dir)
+{
+ struct vfio_pci_dma_buf *priv = attachment->dmabuf->priv;
+ struct scatterlist *sgl;
+ struct sg_table *sgt;
+ unsigned int i = 0;
+ int ret;
+
+ dma_resv_assert_held(priv->dmabuf->resv);
+
+ if (!attachment->peer2peer)
+ return ERR_PTR(-EPERM);
+
+ if (priv->revoked)
+ return ERR_PTR(-ENODEV);
+
+ sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+ if (!sgt)
+ return ERR_PTR(-ENOMEM);
+
+ ret = sg_alloc_table(sgt, priv->nr_pages, GFP_KERNEL);
+ if (ret)
+ goto err_kfree_sgt;
+
+ for_each_sg(sgt->sgl, sgl, priv->nr_pages, i)
+ sg_set_page(sgl, priv->pages[i], PAGE_SIZE, 0);
+
+ ret = dma_map_sgtable(attachment->dev, sgt, dir, 0);
+ if (ret < 0)
+ goto err_free_sgt;
+
+ return sgt;
+
+err_free_sgt:
+ sg_free_table(sgt);
+err_kfree_sgt:
+ kfree(sgt);
+ return ERR_PTR(ret);
+}
+
+static void vfio_pci_dma_buf_unmap(struct dma_buf_attachment *attachment,
+ struct sg_table *sgt,
+ enum dma_data_direction dir)
+{
+ dma_unmap_sgtable(attachment->dev, sgt, dir, 0);
+ sg_free_table(sgt);
+ kfree(sgt);
+}
+
+static void release_p2p_pages(struct vfio_pci_dma_buf *priv,
+ unsigned int nr_pages)
+{
+ while (nr_pages > 0 && priv->pages[--nr_pages])
+ pci_free_p2pmem(priv->vdev->pdev,
+ page_to_virt(priv->pages[nr_pages]),
+ PAGE_SIZE);
+}
+
+static void vfio_pci_dma_buf_release(struct dma_buf *dmabuf)
+{
+ struct vfio_pci_dma_buf *priv = dmabuf->priv;
+
+ /*
+ * Either this or vfio_pci_dma_buf_cleanup() will remove from the list.
+ * The refcount prevents both.
+ */
+ if (priv->vdev) {
+ release_p2p_pages(priv, priv->nr_pages);
+ kfree(priv->pages);
+ down_write(&priv->vdev->memory_lock);
+ list_del_init(&priv->dmabufs_elm);
+ up_write(&priv->vdev->memory_lock);
+ vfio_device_put_registration(&priv->vdev->vdev);
+ }
+ kfree(priv);
+}
+
+static const struct dma_buf_ops vfio_pci_dmabuf_ops = {
+ .attach = vfio_pci_dma_buf_attach,
+ .map_dma_buf = vfio_pci_dma_buf_map,
+ .pin = vfio_pci_dma_buf_pin,
+ .unpin = vfio_pci_dma_buf_unpin,
+ .release = vfio_pci_dma_buf_release,
+ .unmap_dma_buf = vfio_pci_dma_buf_unmap,
+ .mmap = vfio_pci_dma_buf_mmap,
+};
+
+static int create_p2p_pages(struct vfio_pci_dma_buf *priv, uint32_t nr_areas,
+ struct vfio_region_p2p_area *p2p_areas)
+{
+ struct pci_dev *pdev = priv->vdev->pdev;
+ resource_size_t bar_size;
+ unsigned int pg = 0;
+ void *vaddr;
+ size_t size;
+ int i, ret;
+
+ for (i = 0; i < nr_areas; i++) {
+ bar_size = pci_resource_len(pdev, p2p_areas[i].region_index);
+ if (p2p_areas[i].offset > bar_size ||
+ p2p_areas[i].offset + p2p_areas[i].length > bar_size) {
+ ret = -ERANGE;
+ goto err;
+ }
+
+ ret = pci_p2pdma_add_resource(pdev,
+ p2p_areas[i].region_index,
+ p2p_areas[i].length,
+ p2p_areas[i].offset);
+ if (ret)
+ goto err;
+
+ vaddr = pci_alloc_p2pmem(pdev, p2p_areas[i].length);
+ if (!vaddr) {
+ ret = -EINVAL;
+ goto err;
+ }
+
+ for (size = 0; size < p2p_areas[i].length;) {
+ priv->pages[pg++] = virt_to_page(vaddr + size);
+ size += PAGE_SIZE;
+ }
+ }
+
+ return 0;
+
+err:
+ release_p2p_pages(priv, pg);
+ return ret;
+}
+
+int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
+ struct vfio_device_feature_dma_buf __user *arg,
+ size_t argsz)
+{
+ struct vfio_device_feature_dma_buf get_dma_buf;
+ struct vfio_region_p2p_area *p2p_areas;
+ DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+ struct vfio_pci_dma_buf *priv;
+ int i, ret;
+
+ ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_GET,
+ sizeof(get_dma_buf));
+ if (ret != 1)
+ return ret;
+
+ if (copy_from_user(&get_dma_buf, arg, sizeof(get_dma_buf)))
+ return -EFAULT;
+
+ p2p_areas = memdup_array_user(&arg->p2p_areas,
+ get_dma_buf.nr_areas,
+ sizeof(*p2p_areas));
+ if (IS_ERR(p2p_areas))
+ return PTR_ERR(p2p_areas);
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ ret = -ERANGE;
+ for (i = 0; i < get_dma_buf.nr_areas; i++) {
+ /*
+ * For PCI the region_index is the BAR number like
+ * everything else.
+ */
+ if (p2p_areas[i].region_index >= VFIO_PCI_ROM_REGION_INDEX) {
+ goto err_free_priv;
+ }
+
+ if (!IS_ALIGNED(p2p_areas[i].offset, PAGE_SIZE) ||
+ !IS_ALIGNED(p2p_areas[i].length, PAGE_SIZE))
+ goto err_free_priv;
+
+ priv->nr_pages += p2p_areas[i].length >> PAGE_SHIFT;
+ }
+
+ if (!priv->nr_pages)
+ goto err_free_priv;
+
+ priv->pages = kmalloc_array(priv->nr_pages,
+ sizeof(*priv->pages), GFP_KERNEL);
+ if (!priv->pages) {
+ ret = -ENOMEM;
+ goto err_free_priv;
+ }
+
+ priv->vdev = vdev;
+ ret = create_p2p_pages(priv, get_dma_buf.nr_areas, p2p_areas);
+ if (ret)
+ goto err_free_priv;
+
+ exp_info.ops = &vfio_pci_dmabuf_ops;
+ exp_info.size = priv->nr_pages << PAGE_SHIFT;
+ exp_info.flags = get_dma_buf.open_flags;
+ exp_info.priv = priv;
+
+ priv->dmabuf = dma_buf_export(&exp_info);
+ if (IS_ERR(priv->dmabuf)) {
+ ret = PTR_ERR(priv->dmabuf);
+ goto err_free_pages;
+ }
+
+ /* dma_buf_put() now frees priv */
+ INIT_LIST_HEAD(&priv->dmabufs_elm);
+ down_write(&vdev->memory_lock);
+ dma_resv_lock(priv->dmabuf->resv, NULL);
+ priv->revoked = !__vfio_pci_memory_enabled(vdev);
+ vfio_device_try_get_registration(&vdev->vdev);
+ list_add_tail(&priv->dmabufs_elm, &vdev->dmabufs);
+ dma_resv_unlock(priv->dmabuf->resv);
+ up_write(&vdev->memory_lock);
+ kfree(p2p_areas);
+
+ /*
+ * dma_buf_fd() consumes the reference, when the file closes the dmabuf
+ * will be released.
+ */
+ return dma_buf_fd(priv->dmabuf, get_dma_buf.open_flags);
+
+err_free_pages:
+ release_p2p_pages(priv, priv->nr_pages);
+err_free_priv:
+ kfree(p2p_areas);
+ kfree(priv->pages);
+ kfree(priv);
+ return ret;
+}
+
+void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked)
+{
+ struct vfio_pci_dma_buf *priv;
+ struct vfio_pci_dma_buf *tmp;
+
+ lockdep_assert_held_write(&vdev->memory_lock);
+
+ list_for_each_entry_safe(priv, tmp, &vdev->dmabufs, dmabufs_elm) {
+ if (!get_file_rcu(&priv->dmabuf->file))
+ continue;
+ if (priv->revoked != revoked) {
+ dma_resv_lock(priv->dmabuf->resv, NULL);
+ priv->revoked = revoked;
+ dma_buf_move_notify(priv->dmabuf);
+ dma_resv_unlock(priv->dmabuf->resv);
+ }
+ dma_buf_put(priv->dmabuf);
+ }
+}
+
+void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device *vdev)
+{
+ struct vfio_pci_dma_buf *priv;
+ struct vfio_pci_dma_buf *tmp;
+
+ down_write(&vdev->memory_lock);
+ list_for_each_entry_safe(priv, tmp, &vdev->dmabufs, dmabufs_elm) {
+ if (!get_file_rcu(&priv->dmabuf->file))
+ continue;
+ dma_resv_lock(priv->dmabuf->resv, NULL);
+ list_del_init(&priv->dmabufs_elm);
+ priv->vdev = NULL;
+ priv->revoked = true;
+ dma_buf_move_notify(priv->dmabuf);
+ dma_resv_unlock(priv->dmabuf->resv);
+ vfio_device_put_registration(&vdev->vdev);
+ dma_buf_put(priv->dmabuf);
+ }
+ up_write(&vdev->memory_lock);
+}
diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index 97422aafaa7b..c605c5cb0078 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -585,10 +585,12 @@ static int vfio_basic_config_write(struct vfio_pci_core_device *vdev, int pos,
virt_mem = !!(le16_to_cpu(*virt_cmd) & PCI_COMMAND_MEMORY);
new_mem = !!(new_cmd & PCI_COMMAND_MEMORY);
- if (!new_mem)
+ if (!new_mem) {
vfio_pci_zap_and_down_write_memory_lock(vdev);
- else
+ vfio_pci_dma_buf_move(vdev, true);
+ } else {
down_write(&vdev->memory_lock);
+ }
/*
* If the user is writing mem/io enable (new_mem/io) and we
@@ -623,6 +625,8 @@ static int vfio_basic_config_write(struct vfio_pci_core_device *vdev, int pos,
*virt_cmd &= cpu_to_le16(~mask);
*virt_cmd |= cpu_to_le16(new_cmd & mask);
+ if (__vfio_pci_memory_enabled(vdev))
+ vfio_pci_dma_buf_move(vdev, false);
up_write(&vdev->memory_lock);
}
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index d94d61b92c1a..d2ef982bdb3e 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -700,6 +700,8 @@ void vfio_pci_core_close_device(struct vfio_device *core_vdev)
#endif
vfio_pci_core_disable(vdev);
+ vfio_pci_dma_buf_cleanup(vdev);
+
mutex_lock(&vdev->igate);
if (vdev->err_trigger) {
eventfd_ctx_put(vdev->err_trigger);
@@ -1246,7 +1248,10 @@ static int vfio_pci_ioctl_reset(struct vfio_pci_core_device *vdev,
*/
vfio_pci_set_power_state(vdev, PCI_D0);
+ vfio_pci_dma_buf_move(vdev, true);
ret = pci_try_reset_function(vdev->pdev);
+ if (__vfio_pci_memory_enabled(vdev))
+ vfio_pci_dma_buf_move(vdev, false);
up_write(&vdev->memory_lock);
return ret;
@@ -1467,11 +1472,10 @@ long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd,
}
EXPORT_SYMBOL_GPL(vfio_pci_core_ioctl);
-static int vfio_pci_core_feature_token(struct vfio_device *device, u32 flags,
- uuid_t __user *arg, size_t argsz)
+static int vfio_pci_core_feature_token(struct vfio_pci_core_device *vdev,
+ u32 flags, uuid_t __user *arg,
+ size_t argsz)
{
- struct vfio_pci_core_device *vdev =
- container_of(device, struct vfio_pci_core_device, vdev);
uuid_t uuid;
int ret;
@@ -1498,6 +1502,9 @@ static int vfio_pci_core_feature_token(struct vfio_device *device, u32 flags,
int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags,
void __user *arg, size_t argsz)
{
+ struct vfio_pci_core_device *vdev =
+ container_of(device, struct vfio_pci_core_device, vdev);
+
switch (flags & VFIO_DEVICE_FEATURE_MASK) {
case VFIO_DEVICE_FEATURE_LOW_POWER_ENTRY:
return vfio_pci_core_pm_entry(device, flags, arg, argsz);
@@ -1507,7 +1514,9 @@ int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags,
case VFIO_DEVICE_FEATURE_LOW_POWER_EXIT:
return vfio_pci_core_pm_exit(device, flags, arg, argsz);
case VFIO_DEVICE_FEATURE_PCI_VF_TOKEN:
- return vfio_pci_core_feature_token(device, flags, arg, argsz);
+ return vfio_pci_core_feature_token(vdev, flags, arg, argsz);
+ case VFIO_DEVICE_FEATURE_DMA_BUF:
+ return vfio_pci_core_feature_dma_buf(vdev, flags, arg, argsz);
default:
return -ENOTTY;
}
@@ -2182,6 +2191,7 @@ int vfio_pci_core_init_dev(struct vfio_device *core_vdev)
mutex_init(&vdev->vma_lock);
INIT_LIST_HEAD(&vdev->vma_list);
INIT_LIST_HEAD(&vdev->sriov_pfs_item);
+ INIT_LIST_HEAD(&vdev->dmabufs);
init_rwsem(&vdev->memory_lock);
xa_init(&vdev->ctx);
@@ -2576,11 +2586,17 @@ static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
* cause the PCI config space reset without restoring the original
* state (saved locally in 'vdev->pm_save').
*/
- list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list)
+ list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list) {
+ vfio_pci_dma_buf_move(cur, true);
vfio_pci_set_power_state(cur, PCI_D0);
+ }
ret = pci_reset_bus(pdev);
+ list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list)
+ if (__vfio_pci_memory_enabled(cur))
+ vfio_pci_dma_buf_move(cur, false);
+
err_undo:
list_for_each_entry(cur, &dev_set->device_list, vdev.dev_set_list) {
if (cur == cur_mem)
diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h
index 5e4fa69aee16..09d3c300918c 100644
--- a/drivers/vfio/pci/vfio_pci_priv.h
+++ b/drivers/vfio/pci/vfio_pci_priv.h
@@ -101,4 +101,27 @@ static inline bool vfio_pci_is_vga(struct pci_dev *pdev)
return (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA;
}
+#ifdef CONFIG_DMA_SHARED_BUFFER
+int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
+ struct vfio_device_feature_dma_buf __user *arg,
+ size_t argsz);
+void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device *vdev);
+void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked);
+#else
+static int
+vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
+ struct vfio_device_feature_dma_buf __user *arg,
+ size_t argsz)
+{
+ return -ENOTTY;
+}
+static inline void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device *vdev)
+{
+}
+static inline void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev,
+ bool revoked)
+{
+}
+#endif
+
#endif
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index a2c8b8bba711..387cce561dad 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -96,6 +96,7 @@ struct vfio_pci_core_device {
struct mutex vma_lock;
struct list_head vma_list;
struct rw_semaphore memory_lock;
+ struct list_head dmabufs;
};
/* Will be exported for vfio pci drivers usage */
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 2b68e6cdf190..47d230c5df25 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1458,6 +1458,31 @@ struct vfio_device_feature_bus_master {
};
#define VFIO_DEVICE_FEATURE_BUS_MASTER 10
+/**
+ * Upon VFIO_DEVICE_FEATURE_GET create a dma_buf fd for the
+ * region selected.
+ *
+ * open_flags are the typical flags passed to open(2), eg O_RDWR, O_CLOEXEC,
+ * etc. offset/length specify a slice of the region to create the dmabuf from.
+ * If both are 0 then the whole region is used.
+ *
+ * Return: The fd number on success, -1 and errno is set on failure.
+ */
+#define VFIO_DEVICE_FEATURE_DMA_BUF 11
+
+struct vfio_region_p2p_area {
+ __u32 region_index;
+ __u32 __pad;
+ __u64 offset;
+ __u64 length;
+};
+
+struct vfio_device_feature_dma_buf {
+ __u32 open_flags;
+ __u32 nr_areas;
+ struct vfio_region_p2p_area p2p_areas[];
+};
+
/* -------- API for Type1 VFIO IOMMU -------- */
/**
