genirq/msi: Add stubs for get_cached_msi_msg/pci_write_msi_msg

A bug fix to the MSIx handling in vfio added references to functions
that may not be defined if MSI is disabled in the kernel, resulting in
this link error:

drivers/built-in.o: In function `vfio_msi_set_vector_signal':
:(.text+0x450808): undefined reference to `get_cached_msi_msg'
:(.text+0x45080c): undefined reference to `write_msi_msg'

As suggested by Alex Williamson, add stub implementations for
get_cached_msi_msg() and pci_write_msi_msg().

In case this bugfix gets backported, please note that the #ifdef
has changed over time, originally both functions were implemented
in drivers/pci/msi.c and controlled by CONFIG_PCI_MSI, while nowadays
get_cached_msi_msg() is part of the generic MSI support and can be
used without PCI.

Fixes: b8f02af096b1 ("vfio/pci: Restore MSIx message prior to enabling")
Signed-off-by: Arnd Bergmann <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Alex Williamson <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Bart Van Assche <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

0 files changed, 0 insertions, 0 deletions