PCI: Add interfaces to store and load the device saved state

For KVM device assignment, we'd like to save off the state of a device
prior to passing it to the guest and restore it later.  We also want
to allow pci_reset_funciton() to be called while the device is owned
by the guest.  This however overwrites and invalidates the struct pci_dev
buffers, so we can't just manually call save and restore.  Add generic
interfaces for the saved state to be stored and reloaded back into
struct pci_dev at a later time.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 61ef8f2..4604d1d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -812,6 +812,10 @@
 /* Power management related routines */
 int pci_save_state(struct pci_dev *dev);
 void pci_restore_state(struct pci_dev *dev);
+struct pci_saved_state *pci_store_saved_state(struct pci_dev *dev);
+int pci_load_saved_state(struct pci_dev *dev, struct pci_saved_state *state);
+int pci_load_and_free_saved_state(struct pci_dev *dev,
+				  struct pci_saved_state **state);
 int __pci_complete_power_transition(struct pci_dev *dev, pci_power_t state);
 int pci_set_power_state(struct pci_dev *dev, pci_power_t state);
 pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state);