linux-stable.git/drivers/vfio, branch v4.16.2

Revert: "vfio-pci: Mask INTx if a device is not capabable of enabling it"

2018-03-22T04:50:19+00:00

This reverts commit 2170dd04316e0754cbbfa4892a25aead39d225f7

The intent of commit 2170dd04316e ("vfio-pci: Mask INTx if a device is
not capabable of enabling it") was to disallow the user from seeing
that the device supports INTx if the platform is incapable of enabling
it.  The detection of this case however incorrectly includes devices
which natively do not support INTx, such as SR-IOV VFs, and further
discussions reveal gaps even for the target use case.

Reported-by: Arjun Vynipadath 
Fixes: 2170dd04316e ("vfio-pci: Mask INTx if a device is not capabable of enabling it")
Signed-off-by: Alex Williamson

vfio: disable filesystem-dax page pinning

2018-03-03T02:00:04+00:00

Filesystem-DAX is incompatible with 'longterm' page pinning. Without
page cache indirection a DAX mapping maps filesystem blocks directly.
This means that the filesystem must not modify a file's block map while
any page in a mapping is pinned. In order to prevent the situation of
userspace holding of filesystem operations indefinitely, disallow
'longterm' Filesystem-DAX mappings.

RDMA has the same conflict and the plan there is to add a 'with lease'
mechanism to allow the kernel to notify userspace that the mapping is
being torn down for block-map maintenance. Perhaps something similar can
be put in place for vfio.

Note that xfs and ext4 still report:

   "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"

...at mount time, and resolving the dax-dma-vs-truncate problem is one
of the last hurdles to remove that designation.

Acked-by: Alex Williamson 
Cc: Michal Hocko 
Cc: kvm@vger.kernel.org
Cc: 
Reported-by: Haozhong Zhang 
Tested-by: Haozhong Zhang 
Fixes: d475c6346a38 ("dax,ext2: replace XIP read and write with DAX I/O")
Reviewed-by: Christoph Hellwig 
Signed-off-by: Dan Williams

vfs: do bulk POLL* -> EPOLL* replacement

2018-02-11T22:34:03+00:00

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro 
Signed-off-by: Linus Torvalds

Merge tag 'vfio-v4.16-rc1' of git://github.com/awilliam/linux-vfio

2018-02-01T21:18:25+00:00

Pull VFIO updates from Alex Williamson:

 - Mask INTx from user if pdev->irq is zero (Alexey Kardashevskiy)

 - Capability helper cleanup (Alex Williamson)

 - Allow mmaps overlapping MSI-X vector table with region capability
   exposing this feature (Alexey Kardashevskiy)

 - mdev static cleanups (Xiongwei Song)

* tag 'vfio-v4.16-rc1' of git://github.com/awilliam/linux-vfio:
  vfio: mdev: make a couple of functions and structure vfio_mdev_driver static
  vfio-pci: Allow mapping MSIX BAR
  vfio: Simplify capability helper
  vfio-pci: Mask INTx if a device is not capabable of enabling it

vfio: mdev: make a couple of functions and structure vfio_mdev_driver static

2018-01-09T19:13:08+00:00

The functions vfio_mdev_probe, vfio_mdev_remove and the structure
vfio_mdev_driver are only used in this file, so make them static.

Clean up sparse warnings:
drivers/vfio/mdev/vfio_mdev.c:114:5: warning: no previous prototype
for 'vfio_mdev_probe' [-Wmissing-prototypes]
drivers/vfio/mdev/vfio_mdev.c:121:6: warning: no previous prototype
for 'vfio_mdev_remove' [-Wmissing-prototypes]

Signed-off-by: Xiongwei Song 
Reviewed-by: Quan Xu 
Reviewed-by: Liu, Yi L 
Reviewed-by: Kirti Wankhede 
Signed-off-by: Alex Williamson

vfio-pci: Allow mapping MSIX BAR

2017-12-20T17:05:06+00:00

By default VFIO disables mapping of MSIX BAR to the userspace as
the userspace may program it in a way allowing spurious interrupts;
instead the userspace uses the VFIO_DEVICE_SET_IRQS ioctl.
In order to eliminate guessing from the userspace about what is
mmapable, VFIO also advertises a sparse list of regions allowed to mmap.

This works fine as long as the system page size equals to the MSIX
alignment requirement which is 4KB. However with a bigger page size
the existing code prohibits mapping non-MSIX parts of a page with MSIX
structures so these parts have to be emulated via slow reads/writes on
a VFIO device fd. If these emulated bits are accessed often, this has
serious impact on performance.

This allows mmap of the entire BAR containing MSIX vector table.

This removes the sparse capability for PCI devices as it becomes useless.

As the userspace needs to know for sure whether mmapping of the MSIX
vector containing data can succeed, this adds a new capability -
VFIO_REGION_INFO_CAP_MSIX_MAPPABLE - which explicitly tells the userspace
that the entire BAR can be mmapped.

This does not touch the MSIX mangling in the BAR read/write handlers as
we are doing this just to enable direct access to non MSIX registers.

Signed-off-by: Alexey Kardashevskiy 
[aw - fixup whitespace, trim function name]
Signed-off-by: Alex Williamson

vfio: Simplify capability helper

2017-12-20T16:53:54+00:00

The vfio_info_add_capability() helper requires the caller to pass a
capability ID, which it then uses to fill in header fields, assuming
hard coded versions.  This makes for an awkward and rigid interface.
The only thing we want this helper to do is allocate sufficient
space in the caps buffer and chain this capability into the list.
Reduce it to that simple task.

Reviewed-by: Alexey Kardashevskiy 
Acked-by: Zhenyu Wang 
Reviewed-by: Kirti Wankhede 
Reviewed-by: Peter Xu 
Reviewed-by: Eric Auger 
Signed-off-by: Alex Williamson

vfio-pci: Mask INTx if a device is not capabable of enabling it

2017-12-20T16:53:52+00:00

At the moment VFIO rightfully assumes that INTx is supported if
the interrupt pin is not set to zero in the device config space.
However if that is not the case (the pin is not zero but pdev->irq is),
vfio_intx_enable() fails.

In order to prevent the userspace from trying to enable INTx when we know
that it cannot work, let's mask the PCI_INTERRUPT_PIN register.

Signed-off-by: Alexey Kardashevskiy 
Signed-off-by: Alex Williamson

annotate poll-related wait keys

2017-11-27T21:19:54+00:00

__poll_t is also used as wait key in some waitqueues.
Verify that wait_..._poll() gets __poll_t as key and
provide a helper for wakeup functions to get back to
that __poll_t value.

Signed-off-by: Al Viro

anntotate the places where ->poll() return values go

2017-11-27T21:19:53+00:00

Signed-off-by: Al Viro