kernel/linux.git/drivers/vfio/pci, branch linux-4.16.y

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-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

vfio/pci: Virtualize Maximum Read Request Size

2017-10-02T18:39:10+00:00

MRRS defines the maximum read request size a device is allowed to make. Drivers will often increase this to allow more data transfer with a single request. Completions to this request are bound by the MPS setting for the bus. Aside from device quirks (none known), it doesn't seem to make sense to set an MRRS value less than MPS, yet this is a likely scenario given that user drivers do not have a system-wide view of the PCI topology. Virtualize MRRS such that the user can set MRRS >= MPS, but use MPS as the floor value that we'll write to hardware. Signed-off-by: Alex Williamson

vfio/pci: Virtualize Maximum Payload Size

2017-10-02T18:39:09+00:00

With virtual PCI-Express chipsets, we now see userspace/guest drivers trying to match the physical MPS setting to a virtual downstream port. Of course a lone physical device surrounded by virtual interconnects cannot make a correct decision for a proper MPS setting. Instead, let's virtualize the MPS control register so that writes through to hardware are disallowed. Userspace drivers like QEMU assume they can write anything to the device and we'll filter out anything dangerous. Since mismatched MPS can lead to AER and other faults, let's add it to the kernel side rather than relying on userspace virtualization to handle it. Signed-off-by: Alex Williamson Reviewed-by: Eric Auger

vfio/pci: Fix handling of RC integrated endpoint PCIe capability size

2017-07-27T16:39:33+00:00

Root complex integrated endpoints do not have a link and therefore may use a smaller PCIe capability in config space than we expect when building our config map. Add a case for these to avoid reporting an erroneous overlap. Signed-off-by: Alex Williamson

vfio/pci: Use pci_try_reset_function() on initial open

2017-07-26T20:33:15+00:00

Device lock bites again; if a device .remove() callback races a user calling ioctl(VFIO_GROUP_GET_DEVICE_FD), the unbind request will hold the device lock, but the user ioctl may have already taken a vfio_device reference. In the case of a PCI device, the initial open will attempt to reset the device, which again attempts to get the device lock, resulting in deadlock. Use the trylock PCI reset interface and return error on the open path if reset fails due to lock contention. Link: https://lkml.org/lkml/2017/7/25/381 Reported-by: Wen Congyang Signed-off-by: Alex Williamson

vfio/pci: Add Intel XXV710 to hidden INTx devices

2017-06-13T15:22:57+00:00

XXV710 has the same broken INTx behavior as the rest of the X/XL710 series, the interrupt status register is not wired to report pending INTx interrupts, thus we never associate the interrupt to the device. Extend the device IDs to include these so that we hide that the device supports INTx at all to the user. Reported-by: Stefan Assmann Signed-off-by: Alex Williamson Acked-by: Jesse Brandeburg

vfio-pci: Handle error from pci_iomap

2017-01-04T15:34:39+00:00

Here, pci_iomap can fail, handle this case release selected pci regions and return -ENOMEM. Signed-off-by: Arvind Yadav Signed-off-by: Alex Williamson