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2012-10-21vfio: Fix PCI INTx disable consistencyAlex Williamson
commit 899649b7d4ead76c19e39251ca886eebe3f811a8 upstream. The virq_disabled flag tracks the userspace view of INTx masking across interrupt mode changes, but we're not consistently applying this to the interrupt and masking handler notion of the device. Currently if the user sets DisINTx while in MSI or MSIX mode, then returns to INTx mode (ex. rebooting a qemu guest), the hardware has DisINTx+, but the management of INTx thinks it's enabled, making it impossible to actually clear DisINTx. Fix this by updating the handler state when INTx is re-enabled. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-10-21vfio: Move PCI INTx eventfd setting earlierAlex Williamson
commit 9dbdfd23b7638d054f3b0e70c64dfb9f297f2a9f upstream. We need to be ready to recieve an interrupt as soon as we call request_irq, so our eventfd context setting needs to be moved earlier. Without this, an interrupt from our device or one sharing the interrupt line can pass a NULL into eventfd_signal and oops. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-21vfio: Fix virqfd release raceAlex Williamson
vfoi-pci supports a mechanism like KVM's irqfd for unmasking an interrupt through an eventfd. There are two ways to shutdown this interface: 1) close the eventfd, 2) ioctl (such as disabling the interrupt). Both of these do the release through a workqueue, which can result in a segfault if two jobs get queued for the same virqfd. Fix this by protecting the pointer to these virqfds by a spinlock. The vfio pci device will therefore no longer have a reference to it once the release job is queued under lock. On the ioctl side, we still flush the workqueue to ensure that any outstanding releases are completed. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2012-08-22vfio: grab vfio_device reference *before* exposing the sucker via fd_install()Al Viro
It's not critical (anymore) since another thread closing the file will block on ->device_lock before it gets to dropping the final reference, but it's definitely cleaner that way... Acked-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-08-22vfio: get rid of vfio_device_put()/vfio_group_get_device* racesAl Viro
we really need to make sure that dropping the last reference happens under the group->device_lock; otherwise a loop (under device_lock) might find vfio_device instance that is being freed right now, has already dropped the last reference and waits on device_lock to exclude the sucker from the list. Acked-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-08-22vfio: get rid of open-coding kref_put_mutexAl Viro
Acked-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-08-22vfio: don't dereference after kfree...Al Viro
Acked-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-31vfio: Add PCI device driverAlex Williamson
Add PCI device support for VFIO. PCI devices expose regions for accessing config space, I/O port space, and MMIO areas of the device. PCI config access is virtualized in the kernel, allowing us to ensure the integrity of the system, by preventing various accesses while reducing duplicate support across various userspace drivers. I/O port supports read/write access while MMIO also supports mmap of sufficiently sized regions. Support for INTx, MSI, and MSI-X interrupts are provided using eventfds to userspace. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2012-07-31vfio: Type1 IOMMU implementationAlex Williamson
This VFIO IOMMU backend is designed primarily for AMD-Vi and Intel VT-d hardware, but is potentially usable by anything supporting similar mapping functionality. We arbitrarily call this a Type1 backend for lack of a better name. This backend has no IOVA or host memory mapping restrictions for the user and is optimized for relatively static mappings. Mapped areas are pinned into system memory. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2012-07-31vfio: VFIO coreAlex Williamson
VFIO is a secure user level driver for use with both virtual machines and user level drivers. VFIO makes use of IOMMU groups to ensure the isolation of devices in use, allowing unprivileged user access. It's intended that VFIO will replace KVM device assignment and UIO drivers (in cases where the target platform includes a sufficiently capable IOMMU). New in this version of VFIO is support for IOMMU groups managed through the IOMMU core as well as a rework of the API, removing the group merge interface. We now go back to a model more similar to original VFIO with UIOMMU support where the file descriptor obtained from /dev/vfio/vfio allows access to the IOMMU, but only after a group is added, avoiding the previous privilege issues with this type of model. IOMMU support is also now fully modular as IOMMUs have vastly different interface requirements on different platforms. VFIO users are able to query and initialize the IOMMU model of their choice. Please see the follow-on Documentation commit for further description and usage example. Signed-off-by: Alex Williamson <alex.williamson@redhat.com>