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...@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