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 <kevin.tian@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Link: https://lore.kernel.org/r/8-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Jason Gunthorpe
Alex Williamson
Родитель
3e5449d5f9
Коммит
6a985ae80b
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@ -556,7 +556,7 @@ static int vfio_pci_fill_devs(struct pci_dev *pdev, void *data)
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struct vfio_pci_group_info {
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int count;
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struct vfio_group **groups;
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struct file **files;
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};
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static bool vfio_pci_dev_below_slot(struct pci_dev *pdev, struct pci_slot *slot)
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@ -1018,10 +1018,10 @@ reset_info_exit:
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} else if (cmd == VFIO_DEVICE_PCI_HOT_RESET) {
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struct vfio_pci_hot_reset hdr;
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int32_t *group_fds;
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struct vfio_group **groups;
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struct file **files;
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struct vfio_pci_group_info info;
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bool slot = false;
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int group_idx, count = 0, ret = 0;
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int file_idx, count = 0, ret = 0;
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minsz = offsetofend(struct vfio_pci_hot_reset, count);
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@ -1054,17 +1054,17 @@ reset_info_exit:
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return -EINVAL;
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group_fds = kcalloc(hdr.count, sizeof(*group_fds), GFP_KERNEL);
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groups = kcalloc(hdr.count, sizeof(*groups), GFP_KERNEL);
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if (!group_fds || !groups) {
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files = kcalloc(hdr.count, sizeof(*files), GFP_KERNEL);
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if (!group_fds || !files) {
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kfree(group_fds);
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kfree(groups);
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kfree(files);
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return -ENOMEM;
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}
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if (copy_from_user(group_fds, (void __user *)(arg + minsz),
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hdr.count * sizeof(*group_fds))) {
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kfree(group_fds);
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kfree(groups);
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kfree(files);
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return -EFAULT;
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}
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@ -1073,22 +1073,22 @@ reset_info_exit:
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* user interface and store the group and iommu ID. This
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* ensures the group is held across the reset.
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*/
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for (group_idx = 0; group_idx < hdr.count; group_idx++) {
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struct vfio_group *group;
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struct fd f = fdget(group_fds[group_idx]);
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if (!f.file) {
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for (file_idx = 0; file_idx < hdr.count; file_idx++) {
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struct file *file = fget(group_fds[file_idx]);
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if (!file) {
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ret = -EBADF;
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break;
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}
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group = vfio_group_get_external_user(f.file);
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fdput(f);
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if (IS_ERR(group)) {
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ret = PTR_ERR(group);
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/* Ensure the FD is a vfio group FD.*/
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if (!vfio_file_iommu_group(file)) {
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fput(file);
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ret = -EINVAL;
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break;
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}
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groups[group_idx] = group;
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files[file_idx] = file;
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}
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kfree(group_fds);
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@ -1098,15 +1098,15 @@ reset_info_exit:
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goto hot_reset_release;
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info.count = hdr.count;
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info.groups = groups;
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info.files = files;
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ret = vfio_pci_dev_set_hot_reset(vdev->vdev.dev_set, &info);
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hot_reset_release:
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for (group_idx--; group_idx >= 0; group_idx--)
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vfio_group_put_external_user(groups[group_idx]);
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for (file_idx--; file_idx >= 0; file_idx--)
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fput(files[file_idx]);
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kfree(groups);
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kfree(files);
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return ret;
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} else if (cmd == VFIO_DEVICE_IOEVENTFD) {
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struct vfio_device_ioeventfd ioeventfd;
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@ -1972,7 +1972,7 @@ static bool vfio_dev_in_groups(struct vfio_pci_core_device *vdev,
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unsigned int i;
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for (i = 0; i < groups->count; i++)
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if (groups->groups[i] == vdev->vdev.group)
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if (vfio_file_has_dev(groups->files[i], &vdev->vdev))
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return true;
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return false;
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}
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@ -1633,58 +1633,6 @@ static const struct file_operations vfio_device_fops = {
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.mmap = vfio_device_fops_mmap,
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};
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/*
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* External user API, exported by symbols to be linked dynamically.
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*
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* The protocol includes:
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* 1. do normal VFIO init operation:
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* - opening a new container;
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* - attaching group(s) to it;
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* - setting an IOMMU driver for a container.
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* When IOMMU is set for a container, all groups in it are
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* considered ready to use by an external user.
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*
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* 2. User space passes a group fd to an external user.
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* The external user calls vfio_group_get_external_user()
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* to verify that:
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* - the group is initialized;
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* - IOMMU is set for it.
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* If both checks passed, vfio_group_get_external_user()
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* increments the container user counter to prevent
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* the VFIO group from disposal before KVM exits.
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*
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* 3. When the external KVM finishes, it calls
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* vfio_group_put_external_user() to release the VFIO group.
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* This call decrements the container user counter.
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*/
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struct vfio_group *vfio_group_get_external_user(struct file *filep)
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{
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struct vfio_group *group = filep->private_data;
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int ret;
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if (filep->f_op != &vfio_group_fops)
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return ERR_PTR(-EINVAL);
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ret = vfio_group_add_container_user(group);
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if (ret)
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return ERR_PTR(ret);
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/*
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* Since the caller holds the fget on the file group->users must be >= 1
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*/
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vfio_group_get(group);
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return group;
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}
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EXPORT_SYMBOL_GPL(vfio_group_get_external_user);
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void vfio_group_put_external_user(struct vfio_group *group)
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{
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vfio_group_try_dissolve_container(group);
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vfio_group_put(group);
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}
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EXPORT_SYMBOL_GPL(vfio_group_put_external_user);
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/**
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* vfio_file_iommu_group - Return the struct iommu_group for the vfio group file
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* @file: VFIO group file
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@ -1752,6 +1700,24 @@ void vfio_file_set_kvm(struct file *file, struct kvm *kvm)
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}
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EXPORT_SYMBOL_GPL(vfio_file_set_kvm);
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/**
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* vfio_file_has_dev - True if the VFIO file is a handle for device
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* @file: VFIO file to check
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* @device: Device that must be part of the file
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*
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* Returns true if given file has permission to manipulate the given device.
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*/
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bool vfio_file_has_dev(struct file *file, struct vfio_device *device)
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{
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struct vfio_group *group = file->private_data;
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if (file->f_op != &vfio_group_fops)
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return false;
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return group == device->group;
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}
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EXPORT_SYMBOL_GPL(vfio_file_has_dev);
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/*
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* Sub-module support
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*/
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@ -138,11 +138,10 @@ int vfio_mig_get_next_state(struct vfio_device *device,
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/*
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* External user API
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*/
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extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
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extern void vfio_group_put_external_user(struct vfio_group *group);
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extern struct iommu_group *vfio_file_iommu_group(struct file *file);
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extern bool vfio_file_enforced_coherent(struct file *file);
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extern void vfio_file_set_kvm(struct file *file, struct kvm *kvm);
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extern bool vfio_file_has_dev(struct file *file, struct vfio_device *device);
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#define VFIO_PIN_PAGES_MAX_ENTRIES (PAGE_SIZE/sizeof(unsigned long))
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