Export vfio dma-buf specific info by attaching vfio_dma_buf_data in
struct dma_buf::priv. Provide a helper vfio_dma_buf_get_data() for
importers to fetch these data. Exporters identify VFIO dma-buf by
successfully getting these data.
VFIO dma-buf supports disabling host access to these exported MMIO
regions when the device is converted to private. Exporters like KVM
need to identify this type of dma-buf to decide if it is good to use.
KVM only allows host unaccessible MMIO regions been mapped in private
roots.
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/vfio_pci_dmabuf.c | 18 ++++++++++++++++++
include/linux/vfio.h | 18 ++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c
index cf9a90448856..4011545db3ad 100644
--- a/drivers/vfio/pci/vfio_pci_dmabuf.c
+++ b/drivers/vfio/pci/vfio_pci_dmabuf.c
@@ -10,6 +10,8 @@
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;
@@ -300,6 +302,8 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags,
priv->nr_ranges = get_dma_buf.nr_ranges;
priv->dma_ranges = dma_ranges;
+ priv->export_data.kvm = vdev->vdev.kvm;
+
ret = check_dma_ranges(priv, &dmabuf_size);
if (ret)
goto err_free_priv;
@@ -391,3 +395,17 @@ 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);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index ba65bbdffd0b..d521d2c01a92 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -9,6 +9,7 @@
#define VFIO_H
+#include <linux/dma-buf.h>
#include <linux/iommu.h>
#include <linux/mm.h>
#include <linux/workqueue.h>
@@ -383,4 +384,21 @@ 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 {
+ 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 */
--
2.25.1