| Message ID | 162818326742.1511194.1366505678218237973.stgit@omen (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vfio: device fd address space and vfio-pci mmap invalidation cleanup | expand |
On Thu, Aug 05, 2021 at 11:07:47AM -0600, Alex Williamson wrote: > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index 1e4fc69fee7d..42ca93be152a 100644 > +++ b/drivers/vfio/vfio.c > @@ -875,6 +875,22 @@ struct vfio_device *vfio_device_get_from_dev(struct device *dev) > } > EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); > > +static const struct file_operations vfio_device_fops; > + > +int vfio_device_vma_to_pfn(struct vfio_device *device, > + struct vm_area_struct *vma, unsigned long *pfn) A comment here describing the locking conditions the caller must meet would be a good addition.. It looks like this can only work under the i_mmap_lock and the returned pfn can only be taken outside that lock if it is placed in a VMA Maybe this is not a great API then? Should it be 'populate vma' and call io_remap_pfn_range under the op? Jason
On Thu, Aug 05, 2021 at 10:01:46PM -0300, Jason Gunthorpe wrote: > On Thu, Aug 05, 2021 at 11:07:47AM -0600, Alex Williamson wrote: > > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > > index 1e4fc69fee7d..42ca93be152a 100644 > > +++ b/drivers/vfio/vfio.c > > @@ -875,6 +875,22 @@ struct vfio_device *vfio_device_get_from_dev(struct device *dev) > > } > > EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); > > > > +static const struct file_operations vfio_device_fops; > > + > > +int vfio_device_vma_to_pfn(struct vfio_device *device, > > + struct vm_area_struct *vma, unsigned long *pfn) > > A comment here describing the locking conditions the caller must meet > would be a good addition.. It looks like this can only work under the > i_mmap_lock and the returned pfn can only be taken outside that lock > if it is placed in a VMA > > Maybe this is not a great API then? Should it be 'populate vma' and > call io_remap_pfn_range under the op? Yes, I think that would be a better API.
> static int vfio_pci_reflck_attach(struct vfio_pci_device *vdev); > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index 1e4fc69fee7d..42ca93be152a 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -875,6 +875,22 @@ struct vfio_device *vfio_device_get_from_dev(struct device *dev) > } > EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); > > +static const struct file_operations vfio_device_fops; If we ned a forward declaration here it would be nice to keep it at the top of the file. Finding a way to not need it would be even better. > + > +int vfio_device_vma_to_pfn(struct vfio_device *device, > + struct vm_area_struct *vma, unsigned long *pfn) > +{ > + if (WARN_ON(!vma->vm_file || vma->vm_file->f_op != &vfio_device_fops || > + vma->vm_file->private_data != device)) > + return -EINVAL; WARN_ON_ONCE? > + > + if (unlikely(!device->ops->vma_to_pfn)) > + return -EPERM; > + > + return device->ops->vma_to_pfn(device, vma, pfn); > +} > +EXPORT_SYMBOL_GPL(vfio_device_vma_to_pfn); This function is only used in vfio.c, so it can be marked static instead of being exported.
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index c526edbf1173..7a9f67cfc0a2 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -1440,10 +1440,12 @@ void vfio_pci_memory_unlock_and_restore(struct vfio_pci_device *vdev, u16 cmd) up_write(&vdev->memory_lock); } -static int vfio_pci_bar_vma_to_pfn(struct vm_area_struct *vma, +static int vfio_pci_bar_vma_to_pfn(struct vfio_device *core_vdev, + struct vm_area_struct *vma, unsigned long *pfn) { - struct vfio_pci_device *vdev = vma->vm_private_data; + struct vfio_pci_device *vdev = + container_of(core_vdev, struct vfio_pci_device, vdev); struct pci_dev *pdev = vdev->pdev; int index; u64 pgoff; @@ -1469,7 +1471,7 @@ static vm_fault_t vfio_pci_mmap_fault(struct vm_fault *vmf) unsigned long vaddr, pfn; vm_fault_t ret = VM_FAULT_SIGBUS; - if (vfio_pci_bar_vma_to_pfn(vma, &pfn)) + if (vfio_pci_bar_vma_to_pfn(&vdev->vdev, vma, &pfn)) return ret; down_read(&vdev->memory_lock); @@ -1742,6 +1744,7 @@ static const struct vfio_device_ops vfio_pci_ops = { .mmap = vfio_pci_mmap, .request = vfio_pci_request, .match = vfio_pci_match, + .vma_to_pfn = vfio_pci_bar_vma_to_pfn, }; static int vfio_pci_reflck_attach(struct vfio_pci_device *vdev); diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 1e4fc69fee7d..42ca93be152a 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -875,6 +875,22 @@ struct vfio_device *vfio_device_get_from_dev(struct device *dev) } EXPORT_SYMBOL_GPL(vfio_device_get_from_dev); +static const struct file_operations vfio_device_fops; + +int vfio_device_vma_to_pfn(struct vfio_device *device, + struct vm_area_struct *vma, unsigned long *pfn) +{ + if (WARN_ON(!vma->vm_file || vma->vm_file->f_op != &vfio_device_fops || + vma->vm_file->private_data != device)) + return -EINVAL; + + if (unlikely(!device->ops->vma_to_pfn)) + return -EPERM; + + return device->ops->vma_to_pfn(device, vma, pfn); +} +EXPORT_SYMBOL_GPL(vfio_device_vma_to_pfn); + static struct vfio_device *vfio_device_get_from_name(struct vfio_group *group, char *buf) { @@ -1407,8 +1423,6 @@ static int vfio_group_add_container_user(struct vfio_group *group) return 0; } -static const struct file_operations vfio_device_fops; - static int vfio_group_get_device_fd(struct vfio_group *group, char *buf) { struct vfio_device *device; diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 712813703e5a..5f07ebe0f85d 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -41,6 +41,7 @@ struct vfio_device { * @match: Optional device name match callback (return: 0 for no-match, >0 for * match, -errno for abort (ex. match with insufficient or incorrect * additional args) + * @vma_to_pfn: Optional pfn from vma lookup against vma mapping device fd */ struct vfio_device_ops { char *name; @@ -55,6 +56,8 @@ struct vfio_device_ops { int (*mmap)(struct vfio_device *vdev, struct vm_area_struct *vma); void (*request)(struct vfio_device *vdev, unsigned int count); int (*match)(struct vfio_device *vdev, char *buf); + int (*vma_to_pfn)(struct vfio_device *vdev, + struct vm_area_struct *vma, unsigned long *pfn); }; extern struct iommu_group *vfio_iommu_group_get(struct device *dev); @@ -68,6 +71,9 @@ extern struct vfio_device *vfio_device_get_from_dev(struct device *dev); extern void vfio_device_put(struct vfio_device *device); extern void vfio_device_unmap_mapping_range(struct vfio_device *device, loff_t start, loff_t len); +extern int vfio_device_vma_to_pfn(struct vfio_device *device, + struct vm_area_struct *vma, + unsigned long *pfn); /* events for the backend driver notify callback */ enum vfio_iommu_notify_type {
Add a new vfio_device_ops callback to allow the vfio device driver to translate a vma mapping of a vfio device fd to a pfn. Implementation limited to vfio-pci here for the purpose of supporting the reverse of unmap_mapping_range(), but expected to be implemented for all vfio device drivers supporting DMA mapping of device memory mmaps. Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> --- drivers/vfio/pci/vfio_pci.c | 9 ++++++--- drivers/vfio/vfio.c | 18 ++++++++++++++++-- include/linux/vfio.h | 6 ++++++ 3 files changed, 28 insertions(+), 5 deletions(-)