From 6a985ae80befcf2c00e7c889336bfe9e9739e2ef Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Wed, 4 May 2022 16:14:46 -0300 Subject: vfio/pci: Use the struct file as the handle not the vfio_group VFIO PCI does a security check as part of hot reset to prove that the user has permission to manipulate all the devices that will be impacted by the reset. Use a new API vfio_file_has_dev() to perform this security check against the struct file directly and remove the vfio_group from VFIO PCI. Since VFIO PCI was the last user of vfio_group_get_external_user() and vfio_group_put_external_user() remove it as well. Reviewed-by: Kevin Tian Reviewed-by: Christoph Hellwig Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/8-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com Signed-off-by: Alex Williamson --- drivers/vfio/vfio.c | 70 ++++++++++++++--------------------------------------- 1 file changed, 18 insertions(+), 52 deletions(-) (limited to 'drivers/vfio/vfio.c') diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index a0f73bd8e53f..1758d96f43f4 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1633,58 +1633,6 @@ static const struct file_operations vfio_device_fops = { .mmap = vfio_device_fops_mmap, }; -/* - * External user API, exported by symbols to be linked dynamically. - * - * The protocol includes: - * 1. do normal VFIO init operation: - * - opening a new container; - * - attaching group(s) to it; - * - setting an IOMMU driver for a container. - * When IOMMU is set for a container, all groups in it are - * considered ready to use by an external user. - * - * 2. User space passes a group fd to an external user. - * The external user calls vfio_group_get_external_user() - * to verify that: - * - the group is initialized; - * - IOMMU is set for it. - * If both checks passed, vfio_group_get_external_user() - * increments the container user counter to prevent - * the VFIO group from disposal before KVM exits. - * - * 3. When the external KVM finishes, it calls - * vfio_group_put_external_user() to release the VFIO group. - * This call decrements the container user counter. - */ -struct vfio_group *vfio_group_get_external_user(struct file *filep) -{ - struct vfio_group *group = filep->private_data; - int ret; - - if (filep->f_op != &vfio_group_fops) - return ERR_PTR(-EINVAL); - - ret = vfio_group_add_container_user(group); - if (ret) - return ERR_PTR(ret); - - /* - * Since the caller holds the fget on the file group->users must be >= 1 - */ - vfio_group_get(group); - - return group; -} -EXPORT_SYMBOL_GPL(vfio_group_get_external_user); - -void vfio_group_put_external_user(struct vfio_group *group) -{ - vfio_group_try_dissolve_container(group); - vfio_group_put(group); -} -EXPORT_SYMBOL_GPL(vfio_group_put_external_user); - /** * vfio_file_iommu_group - Return the struct iommu_group for the vfio group file * @file: VFIO group file @@ -1752,6 +1700,24 @@ void vfio_file_set_kvm(struct file *file, struct kvm *kvm) } EXPORT_SYMBOL_GPL(vfio_file_set_kvm); +/** + * vfio_file_has_dev - True if the VFIO file is a handle for device + * @file: VFIO file to check + * @device: Device that must be part of the file + * + * Returns true if given file has permission to manipulate the given device. + */ +bool vfio_file_has_dev(struct file *file, struct vfio_device *device) +{ + struct vfio_group *group = file->private_data; + + if (file->f_op != &vfio_group_fops) + return false; + + return group == device->group; +} +EXPORT_SYMBOL_GPL(vfio_file_has_dev); + /* * Sub-module support */ -- cgit v1.2.3