linux-toradex.git/include/linux/vfio.h, branch v5.19-rc8

vfio: remove VFIO_GROUP_NOTIFY_SET_KVM

2022-05-24T14:41:18+00:00

Rather than relying on a notifier for associating the KVM with
the group, let's assume that the association has already been
made prior to device_open.  The first time a device is opened
associate the group KVM with the device.

This fixes a user-triggerable oops in GVT.

Reviewed-by: Tony Krowiak 
Reviewed-by: Kevin Tian 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jason Gunthorpe 
Signed-off-by: Matthew Rosato 
Reviewed-by: Jason Gunthorpe 
Acked-by: Zhi Wang 
Link: https://lore.kernel.org/r/20220519183311.582380-2-mjrosato@linux.ibm.com
Signed-off-by: Alex Williamson

vfio/pci: Use the struct file as the handle not the vfio_group

2022-05-13T16:14:20+00:00

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

vfio: Change vfio_group_set_kvm() to vfio_file_set_kvm()

2022-05-13T16:14:20+00:00

Just change the argument from struct vfio_group to struct file *.

Reviewed-by: Kevin Tian 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/6-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson

vfio: Change vfio_external_check_extension() to vfio_file_enforced_coherent()

2022-05-13T16:14:20+00:00

Instead of a general extension check change the function into a limited
test if the iommu_domain has enforced coherency, which is the only thing
kvm needs to query.

Make the new op self contained by properly refcounting the container
before touching it.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/5-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson

vfio: Remove vfio_external_group_match_file()

2022-05-13T16:14:19+00:00

vfio_group_fops_open() ensures there is only ever one struct file open for
any struct vfio_group at any time:

	/* Do we need multiple instances of the group open?  Seems not. */
	opened = atomic_cmpxchg(&group->opened, 0, 1);
	if (opened) {
		vfio_group_put(group);
		return -EBUSY;

Therefor the struct file * can be used directly to search the list of VFIO
groups that KVM keeps instead of using the
vfio_external_group_match_file() callback to try to figure out if the
passed in FD matches the list or not.

Delete vfio_external_group_match_file().

Reviewed-by: Kevin Tian 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Yi Liu 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/4-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson

vfio: Change vfio_external_user_iommu_id() to vfio_file_iommu_group()

2022-05-13T16:14:19+00:00

The only caller wants to get a pointer to the struct iommu_group
associated with the VFIO group file. Instead of returning the group ID
then searching sysfs for that string to get the struct iommu_group just
directly return the iommu_group pointer already held by the vfio_group
struct.

It already has a safe lifetime due to the struct file kref, the vfio_group
and thus the iommu_group cannot be destroyed while the group file is open.

Reviewed-by: Kevin Tian 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Yi Liu 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/3-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson

vfio/pci: Remove vfio_device_get_from_dev()

2022-05-11T19:32:56+00:00

The last user of this function is in PCI callbacks that want to convert
their struct pci_dev to a vfio_device. Instead of searching use the
vfio_device available trivially through the drvdata.

When a callback in the device_driver is called, the caller must hold the
device_lock() on dev. The purpose of the device_lock is to prevent
remove() from being called (see __device_release_driver), and allow the
driver to safely interact with its drvdata without races.

The PCI core correctly follows this and holds the device_lock() when
calling error_detected (see report_error_detected) and
sriov_configure (see sriov_numvfs_store).

Further, since the drvdata holds a positive refcount on the vfio_device
any access of the drvdata, under the device_lock(), from a driver callback
needs no further protection or refcounting.

Thus the remark in the vfio_device_get_from_dev() comment does not apply
here, VFIO PCI drivers all call vfio_unregister_group_dev() from their
remove callbacks under the device_lock() and cannot race with the
remaining callers.

Reviewed-by: Kevin Tian 
Reviewed-by: Shameer Kolothum 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/2-v4-c841817a0349+8f-vfio_get_from_dev_jgg@nvidia.com
Signed-off-by: Alex Williamson

vfio: Remove dead code

2022-05-11T19:13:00+00:00

Now that callers have been updated to use the vfio_device APIs the driver
facing group interface is no longer used, delete it:

- vfio_group_get_external_user_from_dev()
- vfio_group_pin_pages()
- vfio_group_unpin_pages()
- vfio_group_iommu_domain()

--

Reviewed-by: Christoph Hellwig 
Reviewed-by: Kevin Tian 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/6-v4-8045e76bf00b+13d-vfio_mdev_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson

vfio/mdev: Pass in a struct vfio_device * to vfio_dma_rw()

2022-05-11T19:12:59+00:00

Every caller has a readily available vfio_device pointer, use that instead
of passing in a generic struct device. Change vfio_dma_rw() to take in the
struct vfio_device and move the container users that would have been held
by vfio_group_get_external_user_from_dev() to vfio_dma_rw() directly, like
vfio_pin/unpin_pages().

Reviewed-by: Christoph Hellwig 
Reviewed-by: Kevin Tian 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/4-v4-8045e76bf00b+13d-vfio_mdev_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson

vfio/mdev: Pass in a struct vfio_device * to vfio_pin/unpin_pages()

2022-05-11T19:12:59+00:00

Every caller has a readily available vfio_device pointer, use that instead
of passing in a generic struct device. The struct vfio_device already
contains the group we need so this avoids complexity, extra refcountings,
and a confusing lifecycle model.

Reviewed-by: Christoph Hellwig 
Acked-by: Eric Farman 
Reviewed-by: Jason J. Herne 
Reviewed-by: Tony Krowiak 
Reviewed-by: Kevin Tian 
Signed-off-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/3-v4-8045e76bf00b+13d-vfio_mdev_no_group_jgg@nvidia.com
Signed-off-by: Alex Williamson