[PATCH v4 0/3] Store and load PCI device saved state across function resets

[Alex Williamson <alex.williamson@redhat.com>]

v3 -> v4:
  Renamed struct pci_cap_saved -> struct pci_cap_saved_data and
  the element name within struct pci_cap_saved_state to cap.

Jesse, I hope this helps provide the clarification you were looking
for.  Thanks for the comments.

v2 -> v3:
  Saved structure has variable contents.

v1 -> v2:
  Make the pointer passed around less opaque for type safety.

Bug https://bugs.launchpad.net/qemu/+bug/754591 is caused because
the KVM module attempts to do a pci_save_state() before assigning
the device to a VM, expecting that the saved state will remain
valid until we release the device.  This is in conflict with our
need to reset devices using PCI sysfs during a VM reset to
quiesce the device.  Any calls to pci_reset_function() will
overwrite the device saved stated prior to reset, and reload and
invalidate the state after.  KVM then ends up trying to restore
the state, but it's already invalid, so the device ends up with
reset values.

This series adds a mechanism to pull the saved state off the
struct pci_dev and reload it later.  Thanks,

Alex

---

Alex Williamson (3):
      KVM: Use pci_store/load_saved_state() around VM device usage
      PCI: Add interfaces to store and load the device saved state
      PCI: Track the size of each saved capability data area


 drivers/pci/pci.c        |  110 ++++++++++++++++++++++++++++++++++++++++++++--
 include/linux/kvm_host.h |    1 
 include/linux/pci.h      |   15 +++++-
 virt/kvm/assigned-dev.c  |   18 ++++++--
 4 files changed, 132 insertions(+), 12 deletions(-)