linux-stable.git/include/linux/vfio.h, branch v5.19.3

vfio: Split migration ops from main device ops

2022-08-17T13:15:48+00:00

[ Upstream commit 6e97eba8ad8748fabb795cffc5d9e1a7dcfd7367 ]

vfio core checks whether the driver sets some migration op (e.g.
set_state/get_state) and accordingly calls its op.

However, currently mlx5 driver sets the above ops without regards to its
migration caps.

This might lead to unexpected usage/Oops if user space may call to the
above ops even if the driver doesn't support migration. As for example,
the migration state_mutex is not initialized in that case.

The cleanest way to manage that seems to split the migration ops from
the main device ops, this will let the driver setting them separately
from the main ops when it's applicable.

As part of that, validate ops construction on registration and include a
check for VFIO_MIGRATION_STOP_COPY since the uAPI claims it must be set
in migration_flags.

HISI driver was changed as well to match this scheme.

This scheme may enable down the road to come with some extra group of
ops (e.g. DMA log) that can be set without regards to the other options
based on driver caps.

Fixes: 6fadb021266d ("vfio/mlx5: Implement vfio_pci driver for mlx5 devices")
Reviewed-by: Kevin Tian 
Signed-off-by: Yishai Hadas 
Link: https://lore.kernel.org/r/20220628155910.171454-3-yishaih@nvidia.com
Signed-off-by: Alex Williamson 
Signed-off-by: Sasha Levin

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