@@ -9,6 +9,8 @@
MODULE_IMPORT_NS("DMA_BUF");
struct vfio_pci_dma_buf {
+ struct vfio_dma_buf_data export_data;
+
struct dma_buf *dmabuf;
struct vfio_pci_core_device *vdev;
struct list_head dmabufs_elm;
@@ -156,6 +158,14 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
priv->vdev = vdev;
priv->nr_ranges = get_dma_buf.nr_ranges;
priv->dma_ranges = dma_ranges;
+ /*
+ * KVM expects private dma_buf. An private dma_buf must not
+ * support dma_buf_ops.map_dma_buf/mmap/vmap(). The exporter must also
+ * ensure no side channel access for the backend resource, e.g.
+ * vfio_device_ops.mmap() should not be supported.
+ */
+ priv->export_data.is_private = vdev->vdev.is_private;
+ priv->export_data.kvm = vdev->vdev.kvm;
ret = check_dma_ranges(priv, &dmabuf_size);
if (ret)
@@ -247,3 +257,17 @@ void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device *vdev)
}
up_write(&vdev->memory_lock);
}
+
+/*
+ * Only vfio/pci implements this, so put the helper here for now.
+ */
+struct vfio_dma_buf_data *vfio_dma_buf_get_data(struct dma_buf *dmabuf)
+{
+ struct vfio_pci_dma_buf *priv = dmabuf->priv;
+
+ if (dmabuf->ops != &vfio_pci_dmabuf_ops)
+ return ERR_PTR(-EINVAL);
+
+ return &priv->export_data;
+}
+EXPORT_SYMBOL_GPL(vfio_dma_buf_get_data);
@@ -9,6 +9,7 @@
#define VFIO_H
+#include <linux/dma-buf.h>
#include <linux/iommu.h>
#include <linux/mm.h>
#include <linux/workqueue.h>
@@ -370,4 +371,22 @@ int vfio_virqfd_enable(void *opaque, int (*handler)(void *, void *),
void vfio_virqfd_disable(struct virqfd **pvirqfd);
void vfio_virqfd_flush_thread(struct virqfd **pvirqfd);
+/*
+ * DMA-buf - generic
+ */
+struct vfio_dma_buf_data {
+ bool is_private;
+ struct kvm *kvm;
+};
+
+#if IS_ENABLED(CONFIG_DMA_SHARED_BUFFER) && IS_ENABLED(CONFIG_VFIO_PCI_CORE)
+struct vfio_dma_buf_data *vfio_dma_buf_get_data(struct dma_buf *dmabuf);
+#else
+static inline
+struct vfio_dma_buf_data *vfio_dma_buf_get_data(struct dma_buf *dmabuf)
+{
+ return NULL;
+}
+#endif
+
#endif /* VFIO_H */
VFIO dma-buf supports exporting host unaccessible MMIO regions for private assignment. Export this info by attaching VFIO specific dma-buf data in struct dma_buf::priv. Provide a helper vfio_dma_buf_get_data() for importers to fetch these data. The exported host unaccessible info are for importers to decide if the dma-buf is good to use. KVM only allows host unaccessible MMIO regions for private MMIO slot. But it is expected other importers (e.g. RDMA driver, IOMMUFD) may also use the dma-buf machanism for P2P in native or non-CoCo VM, in which cases host unaccessible is not required. Also export struct kvm * handler attached to the vfio device. This allows KVM to do another sanity check. MMIO should only be assigned to a CoCo VM if its owner device is already assigned to the same VM. Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com> --- drivers/vfio/pci/dma_buf.c | 24 ++++++++++++++++++++++++ include/linux/vfio.h | 19 +++++++++++++++++++ 2 files changed, 43 insertions(+)