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vfio/pci: Allow passing zero-length fd array in VFIO_DEVICE_PCI_HOT_RESET 

This is the way user to invoke hot-reset for the devices opened by cdev
interface. User should check the flag VFIO_PCI_HOT_RESET_FLAG_DEV_ID_OWNED
in the output of VFIO_DEVICE_GET_PCI_HOT_RESET_INFO ioctl before doing
hot-reset for cdev devices.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718105542.4138-11-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Yi Liu 2023-07-18 03:55:42 -07:00 committed by Alex Williamson
parent b56b7aabcf
commit 71791b9246
2 changed files with 71 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
drivers/vfio/pci/vfio_pci_core.c
View File

@ -181,7 +181,8 @@ no_mmap:
struct vfio_pci_group_info;
static void vfio_pci_dev_set_try_reset(struct vfio_device_set *dev_set);
static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
struct vfio_pci_group_info *groups);
struct vfio_pci_group_info *groups,
struct iommufd_ctx *iommufd_ctx);
/*
* INTx masking requires the ability to disable INTx signaling via PCI_COMMAND
@ -1329,8 +1330,7 @@ vfio_pci_ioctl_pci_hot_reset_groups(struct vfio_pci_core_device *vdev,
if (ret)
return ret;
/* Somewhere between 1 and count is OK */
if (!array_count || array_count > count)
if (array_count > count)
return -EINVAL;
group_fds = kcalloc(array_count, sizeof(*group_fds), GFP_KERNEL);
@ -1379,7 +1379,7 @@ vfio_pci_ioctl_pci_hot_reset_groups(struct vfio_pci_core_device *vdev,
info.count = array_count;
info.files = files;
ret = vfio_pci_dev_set_hot_reset(vdev->vdev.dev_set, &info);
ret = vfio_pci_dev_set_hot_reset(vdev->vdev.dev_set, &info, NULL);
hot_reset_release:
for (file_idx--; file_idx >= 0; file_idx--)
@ -1402,13 +1402,21 @@ static int vfio_pci_ioctl_pci_hot_reset(struct vfio_pci_core_device *vdev,
if (hdr.argsz < minsz || hdr.flags)
return -EINVAL;
/* zero-length array is only for cdev opened devices */
if (!!hdr.count == vfio_device_cdev_opened(&vdev->vdev))
return -EINVAL;
/* Can we do a slot or bus reset or neither? */
if (!pci_probe_reset_slot(vdev->pdev->slot))
slot = true;
else if (pci_probe_reset_bus(vdev->pdev->bus))
return -ENODEV;
if (hdr.count)
return vfio_pci_ioctl_pci_hot_reset_groups(vdev, hdr.count, slot, arg);
return vfio_pci_dev_set_hot_reset(vdev->vdev.dev_set, NULL,
vfio_iommufd_device_ictx(&vdev->vdev));
}
static int vfio_pci_ioctl_ioeventfd(struct vfio_pci_core_device *vdev,
@ -2376,13 +2384,16 @@ const struct pci_error_handlers vfio_pci_core_err_handlers = {
};
EXPORT_SYMBOL_GPL(vfio_pci_core_err_handlers);
static bool vfio_dev_in_groups(struct vfio_pci_core_device *vdev,
static bool vfio_dev_in_groups(struct vfio_device *vdev,
struct vfio_pci_group_info *groups)
{
unsigned int i;
if (!groups)
return false;
for (i = 0; i < groups->count; i++)
if (vfio_file_has_dev(groups->files[i], &vdev->vdev))
if (vfio_file_has_dev(groups->files[i], vdev))
return true;
return false;
}
@ -2458,7 +2469,8 @@ unwind:
* get each memory_lock.
*/
static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
struct vfio_pci_group_info *groups)
struct vfio_pci_group_info *groups,
struct iommufd_ctx *iommufd_ctx)
{
struct vfio_pci_core_device *cur_mem;
struct vfio_pci_core_device *cur_vma;
@ -2488,11 +2500,38 @@ static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set,
goto err_unlock;
list_for_each_entry(cur_vma, &dev_set->device_list, vdev.dev_set_list) {
bool owned;
/*
* Test whether all the affected devices are contained by the
* set of groups provided by the user.
* Test whether all the affected devices can be reset by the
* user.
*
* If called from a group opened device and the user provides
* a set of groups, all the devices in the dev_set should be
* contained by the set of groups provided by the user.
*
* If called from a cdev opened device and the user provides
* a zero-length array, all the devices in the dev_set must
* be bound to the same iommufd_ctx as the input iommufd_ctx.
* If there is any device that has not been bound to any
* iommufd_ctx yet, check if its iommu_group has any device
* bound to the input iommufd_ctx. Such devices can be
* considered owned by the input iommufd_ctx as the device
* cannot be owned by another iommufd_ctx when its iommu_group
* is owned.
*
* Otherwise, reset is not allowed.
*/
if (!vfio_dev_in_groups(cur_vma, groups)) {
if (iommufd_ctx) {
int devid = vfio_iommufd_get_dev_id(&cur_vma->vdev,
iommufd_ctx);
owned = (devid > 0 || devid == -ENOENT);
} else {
owned = vfio_dev_in_groups(&cur_vma->vdev, groups);
}
if (!owned) {
ret = -EINVAL;
goto err_undo;
}

21
include/uapi/linux/vfio.h
View File

@ -717,6 +717,9 @@ enum {
* affected devices are represented in the dev_set and also owned by
* the user. This flag is available only when
* flag VFIO_PCI_HOT_RESET_FLAG_DEV_ID is set, otherwise reserved.
* When set, user could invoke VFIO_DEVICE_PCI_HOT_RESET with a zero
* length fd array on the calling device as the ownership is validated
* by iommufd_ctx.
*
* Return: 0 on success, -errno on failure:
* -enospc = insufficient buffer, -enodev = unsupported for device.
@ -748,6 +751,24 @@ struct vfio_pci_hot_reset_info {
* VFIO_DEVICE_PCI_HOT_RESET - _IOW(VFIO_TYPE, VFIO_BASE + 13,
* struct vfio_pci_hot_reset)
*
* A PCI hot reset results in either a bus or slot reset which may affect
* other devices sharing the bus/slot. The calling user must have
* ownership of the full set of affected devices as determined by the
* VFIO_DEVICE_GET_PCI_HOT_RESET_INFO ioctl.
*
* When called on a device file descriptor acquired through the vfio
* group interface, the user is required to provide proof of ownership
* of those affected devices via the group_fds array in struct
* vfio_pci_hot_reset.
*
* When called on a direct cdev opened vfio device, the flags field of
* struct vfio_pci_hot_reset_info reports the ownership status of the
* affected devices and this ioctl must be called with an empty group_fds
* array. See above INFO ioctl definition for ownership requirements.
*
* Mixed usage of legacy groups and cdevs across the set of affected
* devices is not supported.
*
* Return: 0 on success, -errno on failure.
*/
struct vfio_pci_hot_reset {