Since converting BAR mmap()s to using DMABUFs, we lose the original device path in /proc/<pid>/maps, lsof, etc. Generate a debug-oriented synthetic 'filename' based on the cdev, plus BDF, plus resource index.
This applies only to BAR mappings via the VFIO device fd, as explicitly-exported DMABUFs are named by userspace via the DMA_BUF_SET_NAME ioctl.
Signed-off-by: Matt Evans matt@ozlabs.org Reviewed-by: Pranjal Shrivastava praan@google.com --- drivers/vfio/pci/vfio_pci_dmabuf.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c index 46b3cf5dc94b..51606ff3cdc6 100644 --- a/drivers/vfio/pci/vfio_pci_dmabuf.c +++ b/drivers/vfio/pci/vfio_pci_dmabuf.c @@ -4,6 +4,7 @@ #include <linux/dma-buf-mapping.h> #include <linux/pci-p2pdma.h> #include <linux/dma-resv.h> +#include <uapi/linux/dma-buf.h>
#include "vfio_pci_priv.h"
@@ -486,6 +487,7 @@ int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev, { struct vfio_pci_dma_buf *priv; unsigned long vma_pgoff = vma->vm_pgoff & (VFIO_PCI_OFFSET_MASK >> PAGE_SHIFT); + char *bufname; int ret;
priv = kzalloc_obj(*priv); @@ -498,6 +500,15 @@ int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev, goto err_free_priv; }
+ bufname = kasprintf(GFP_KERNEL, "%s:%s/%x", + dev_name(&vdev->vdev.device), pci_name(vdev->pdev), + res_index); + + if (!bufname) { + ret = -ENOMEM; + goto err_free_phys; + } + /* * The DMABUF begins from the mmap()'s BAR offset, i.e. the * start of the VMA corresponds to byte 0 of the DMABUF and @@ -516,7 +527,7 @@ int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev, priv->provider = pcim_p2pdma_provider(vdev->pdev, res_index); if (!priv->provider) { ret = -EINVAL; - goto err_free_phys; + goto err_free_name; }
priv->phys_vec[0].paddr = phys_start + ((u64)vma_pgoff << PAGE_SHIFT); @@ -524,7 +535,7 @@ int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev,
ret = vfio_pci_dmabuf_export(vdev, priv, O_CLOEXEC | O_RDWR); if (ret) - goto err_free_phys; + goto err_free_name;
/* * Ownership of the DMABUF file transfers to the VMA so that @@ -539,8 +550,15 @@ int vfio_pci_core_mmap_prep_dmabuf(struct vfio_pci_core_device *vdev, vma->vm_file = priv->dmabuf->file; vma->vm_private_data = priv;
+ spin_lock(&priv->dmabuf->name_lock); + kfree(priv->dmabuf->name); + priv->dmabuf->name = bufname; + spin_unlock(&priv->dmabuf->name_lock); + return 0;
+err_free_name: + kfree(bufname); err_free_phys: kfree(priv->phys_vec); err_free_priv: