Bypass the IGD initialization when -ENODEV returns,
that should be the case if opregion is not available for IGD
or within discrete graphics device's option ROM,
or host/lpc bridge is not found.

Then use of -ENODEV here means no special device resources found
which needs special care for VFIO, but we still allow other normal
device resource access.

Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Xiong Zhang <xiong.y.zhang@intel.com>
Cc: Hang Yuan <hang.yuan@linux.intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Fred Gao <fred.gao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

The ioeventfd is called under spinlock with interrupts disabled,
therefore if the memory lock is contended defer code that might
sleep to a thread context.

Fixes: bc93b9ae0151 ("vfio-pci: Avoid recursive read-lock usage")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=209253#c1
Reported-by: Ian Pilcher <arequipeno@gmail.com>
Tested-by: Ian Pilcher <arequipeno@gmail.com>
Tested-by: Justin Gatzen <justin.gatzen@gmail.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Pull VFIO updates from Alex Williamson:

 - New fsl-mc vfio bus driver supporting userspace drivers of objects
   within NXP's DPAA2 architecture (Diana Craciun)

 - Support for exposing zPCI information on s390 (Matthew Rosato)

 - Fixes for "detached" VFs on s390 (Matthew Rosato)

 - Fixes for pin-pages and dma-rw accesses (Yan Zhao)

 - Cleanups and optimize vconfig regen (Zenghui Yu)

 - Fix duplicate irq-bypass token registration (Alex Williamson)

* tag 'vfio-v5.10-rc1' of git://github.com/awilliam/linux-vfio: (30 commits)
  vfio iommu type1: Fix memory leak in vfio_iommu_type1_pin_pages
  vfio/pci: Clear token on bypass registration failure
  vfio/fsl-mc: fix the return of the uninitialized variable ret
  vfio/fsl-mc: Fix the dead code in vfio_fsl_mc_set_irq_trigger
  vfio/fsl-mc: Fixed vfio-fsl-mc driver compilation on 32 bit
  MAINTAINERS: Add entry for s390 vfio-pci
  vfio-pci/zdev: Add zPCI capabilities to VFIO_DEVICE_GET_INFO
  vfio/fsl-mc: Add support for device reset
  vfio/fsl-mc: Add read/write support for fsl-mc devices
  vfio/fsl-mc: trigger an interrupt via eventfd
  vfio/fsl-mc: Add irq infrastructure for fsl-mc devices
  vfio/fsl-mc: Added lock support in preparation for interrupt handling
  vfio/fsl-mc: Allow userspace to MMAP fsl-mc device MMIO regions
  vfio/fsl-mc: Implement VFIO_DEVICE_GET_REGION_INFO ioctl call
  vfio/fsl-mc: Implement VFIO_DEVICE_GET_INFO ioctl
  vfio/fsl-mc: Scan DPRC objects on vfio-fsl-mc driver bind
  vfio: Introduce capability definitions for VFIO_DEVICE_GET_INFO
  s390/pci: track whether util_str is valid in the zpci_dev
  s390/pci: stash version in the zpci_dev
  vfio/fsl-mc: Add VFIO framework skeleton for fsl-mc devices
  ...

The eventfd context is used as our irqbypass token, therefore if an
eventfd is re-used, our token is the same.  The irqbypass code will
return an -EBUSY in this case, but we'll still attempt to unregister
the producer, where if that duplicate token still exists, results in
removing the wrong object.  Clear the token of failed producers so
that they harmlessly fall out when unregistered.

Fixes: 6d7425f109d2 ("vfio: Register/unregister irq_bypass_producer")
Reported-by: guomin chen <guomin_chen@sina.com>
Tested-by: guomin chen <guomin_chen@sina.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

The preceding patches have ensured that core dumping properly takes the
mmap_lock.  Thanks to that, we can now remove mmget_still_valid() and all
its users.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20200827114932.3572699-8-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Define a new configuration entry VFIO_PCI_ZDEV for VFIO/PCI.

When this s390-only feature is configured we add capabilities to the
VFIO_DEVICE_GET_INFO ioctl that describe features of the associated
zPCI device and its underlying hardware.

This patch is based on work previously done by Pierre Morel.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

While it is true that devices with is_virtfn=1 will have a Memory Space
Enable bit that is hard-wired to 0, this is not the only case where we
see this behavior -- For example some bare-metal hypervisors lack
Memory Space Enable bit emulation for devices not setting is_virtfn
(s390). Fix this by instead checking for the newly-added
no_command_memory bit which directly denotes the need for
PCI_COMMAND_MEMORY emulation in vfio.

Fixes: abafbc551fdd ("vfio-pci: Invalidate mmaps and block MMIO access on disabled memory")
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Now we regenerate vconfig for all the BARs via vfio_bar_fixup(), every
time any offset of any of them are read.  Though BARs aren't re-read
regularly, the regeneration can be avoided if no BARs had been written
since they were last read, in which case vdev->bardirty is false.

Let's return immediately in vfio_bar_fixup() if bardirty is false.

Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>