linux.git/drivers/vfio/mdev/mdev_core.c, branch v5.2-rc2

Merge tag 'iommu-updates-v5.2' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/joro/iommu

2019-05-13T13:23:18+00:00

Pull IOMMU updates from Joerg Roedel:

 - ATS support for ARM-SMMU-v3.

 - AUX domain support in the IOMMU-API and the Intel VT-d driver. This
   adds support for multiple DMA address spaces per (PCI-)device. The
   use-case is to multiplex devices between host and KVM guests in a
   more flexible way than supported by SR-IOV.

 - the rest are smaller cleanups and fixes, two of which needed to be
   reverted after testing in linux-next.

* tag 'iommu-updates-v5.2' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (45 commits)
  Revert "iommu/amd: Flush not present cache in iommu_map_page"
  Revert "iommu/amd: Remove the leftover of bypass support"
  iommu/vt-d: Fix leak in intel_pasid_alloc_table on error path
  iommu/vt-d: Make kernel parameter igfx_off work with vIOMMU
  iommu/vt-d: Set intel_iommu_gfx_mapped correctly
  iommu/amd: Flush not present cache in iommu_map_page
  iommu/vt-d: Cleanup: no spaces at the start of a line
  iommu/vt-d: Don't request page request irq under dmar_global_lock
  iommu/vt-d: Use struct_size() helper
  iommu/mediatek: Fix leaked of_node references
  iommu/amd: Remove amd_iommu_pd_list
  iommu/arm-smmu: Log CBFRSYNRA register on context fault
  iommu/arm-smmu-v3: Don't disable SMMU in kdump kernel
  iommu/arm-smmu-v3: Disable tagged pointers
  iommu/arm-smmu-v3: Add support for PCI ATS
  iommu/arm-smmu-v3: Link domains and devices
  iommu/arm-smmu-v3: Add a master->domain pointer
  iommu/arm-smmu-v3: Store SteamIDs in master
  iommu/arm-smmu-v3: Rename arm_smmu_master_data to arm_smmu_master
  ACPI/IORT: Check ATS capability in root complex nodes
  ...

vfio/mdev: Avoid inline get and put parent helpers

2019-05-07T17:23:13+00:00

As section 15 of Documentation/process/coding-style.rst clearly
describes that compiler will be able to optimize code.

Hence drop inline for get and put helpers for parent.

Signed-off-by: Parav Pandit 
Signed-off-by: Alex Williamson

vfio/mdev: Fix aborting mdev child device removal if one fails

2019-05-07T17:23:13+00:00

device_for_each_child() stops executing callback function for remaining
child devices, if callback hits an error.
Each child mdev device is independent of each other.
While unregistering parent device, mdev core must remove all child mdev
devices.
Therefore, mdev_device_remove_cb() always returns success so that
device_for_each_child doesn't abort if one child removal hits error.

While at it, improve remove and unregister functions for below simplicity.

There isn't need to pass forced flag pointer during mdev parent
removal which invokes mdev_device_remove(). So simplify the flow.

mdev_device_remove() is called from two paths.
1. mdev_unregister_driver()
     mdev_device_remove_cb()
       mdev_device_remove()
2. remove_store()
     mdev_device_remove()

Fixes: 7b96953bc640 ("vfio: Mediated device Core driver")
Reviewed-by: Maxim Levitsky 
Signed-off-by: Parav Pandit 
Signed-off-by: Alex Williamson

vfio/mdev: Avoid masking error code to EBUSY

2019-05-07T17:23:13+00:00

Instead of masking return error to -EBUSY, return actual error
returned by the driver.

Reviewed-by: Cornelia Huck 
Reviewed-by: Maxim Levitsky 
Signed-off-by: Parav Pandit 
Signed-off-by: Alex Williamson

vfio/mdev: Removed unused kref

2019-05-07T17:23:13+00:00

Remove unused kref from the mdev_device structure.

Fixes: 7b96953bc640 ("vfio: Mediated device Core driver")
Reviewed-by: Cornelia Huck 
Reviewed-by: Kirti Wankhede 
Reviewed-by: Maxim Levitsky 
Signed-off-by: Parav Pandit 
Signed-off-by: Alex Williamson

vfio/mdev: Avoid release parent reference during error path

2019-05-07T17:23:13+00:00

During mdev parent registration in mdev_register_device(),
if parent device is duplicate, it releases the reference of existing
parent device.
This is incorrect. Existing parent device should not be touched.

Fixes: 7b96953bc640 ("vfio: Mediated device Core driver")
Reviewed-by: Cornelia Huck 
Reviewed-by: Kirti Wankhede 
Reviewed-by: Maxim Levitsky 
Signed-off-by: Parav Pandit 
Signed-off-by: Alex Williamson

vfio/mdev: Add iommu related member in mdev_device

2019-04-12T11:00:37+00:00

A parent device might create different types of mediated
devices. For example, a mediated device could be created
by the parent device with full isolation and protection
provided by the IOMMU. One usage case could be found on
Intel platforms where a mediated device is an assignable
subset of a PCI, the DMA requests on behalf of it are all
tagged with a PASID. Since IOMMU supports PASID-granular
translations (scalable mode in VT-d 3.0), this mediated
device could be individually protected and isolated by an
IOMMU.

This patch adds a new member in the struct mdev_device to
indicate that the mediated device represented by mdev could
be isolated and protected by attaching a domain to a device
represented by mdev->iommu_device. It also adds a helper to
add or set the iommu device.

* mdev_device->iommu_device
  - This, if set, indicates that the mediated device could
    be fully isolated and protected by IOMMU via attaching
    an iommu domain to this device. If empty, it indicates
    using vendor defined isolation, hence bypass IOMMU.

* mdev_set/get_iommu_device(dev, iommu_device)
  - Set or get the iommu device which represents this mdev
    in IOMMU's device scope. Drivers don't need to set the
    iommu device if it uses vendor defined isolation.

Cc: Ashok Raj 
Cc: Jacob Pan 
Cc: Kevin Tian 
Cc: Liu Yi L 
Suggested-by: Kevin Tian 
Suggested-by: Alex Williamson 
Signed-off-by: Lu Baolu 
Reviewed-by: Jean-Philippe Brucker 
Reviewed-by: Kirti Wankhede 
Acked-by: Alex Williamson 
Signed-off-by: Joerg Roedel

vfio-mdev: Switch to use new generic UUID API

2019-02-05T18:51:56+00:00

There are new types and helpers that are supposed to be used in new code.

As a preparation to get rid of legacy types and API functions do
the conversion here.

Cc: Kirti Wankhede 
Cc: Alex Williamson 
Signed-off-by: Andy Shevchenko 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Alex Williamson

vfio/mdev: Check globally for duplicate devices

2018-06-08T16:24:27+00:00

When we create an mdev device, we check for duplicates against the
parent device and return -EEXIST if found, but the mdev device
namespace is global since we'll link all devices from the bus.  We do
catch this later in sysfs_do_create_link_sd() to return -EEXIST, but
with it comes a kernel warning and stack trace for trying to create
duplicate sysfs links, which makes it an undesirable response.

Therefore we should really be looking for duplicates across all mdev
parent devices, or as implemented here, against our mdev device list.
Using mdev_list to prevent duplicates means that we can remove
mdev_parent.lock, but in order not to serialize mdev device creation
and removal globally, we add mdev_device.active which allows UUIDs to
be reserved such that we can drop the mdev_list_lock before the mdev
device is fully in place.

Two behavioral notes; first, mdev_parent.lock had the side-effect of
serializing mdev create and remove ops per parent device.  This was
an implementation detail, not an intentional guarantee provided to
the mdev vendor drivers.  Vendor drivers can trivially provide this
serialization internally if necessary.  Second, review comments note
the new -EAGAIN behavior when the device, and in particular the remove
attribute, becomes visible in sysfs.  If a remove is triggered prior
to completion of mdev_device_create() the user will see a -EAGAIN
error.  While the errno is different, receiving an error during this
period is not, the previous implementation returned -ENODEV for the
same condition.  Furthermore, the consistency to the user is improved
in the case where mdev_device_remove_ops() returns error.  Previously
concurrent calls to mdev_device_remove() could see the device
disappear with -ENODEV and return in the case of error.  Now a user
would see -EAGAIN while the device is in this transitory state.

Reviewed-by: Kirti Wankhede 
Reviewed-by: Cornelia Huck 
Acked-by: Halil Pasic 
Acked-by: Zhenyu Wang 
Signed-off-by: Alex Williamson

vfio/mdev: Use a module softdep for vfio_mdev

2017-02-08T20:13:25+00:00

Use an explicit module softdep rather than a request module call such
that the dependency is exposed to userspace.  This allows us to more
easily support modules loaded at initrd time.

Reviewed by: Kirti Wankhede 
Signed-off-by: Alex Williamson