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, this adds 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. Signed-off-by: Arnd Bergmann <[email protected]> Fixes: b8f02af096b1 ("vfio/pci: Restore MSIx message prior to enabling") Link: https://lkml.org/lkml/2014/10/13/124 --- I had a workaround for this hidden in my randconfig tree but have now stumbled over it again, sorry for not following up a couple of years earlier. --- include/linux/msi.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/include/linux/msi.h b/include/linux/msi.h index 0db320b7bb15..a83b84ff70e5 100644 --- a/include/linux/msi.h +++ b/include/linux/msi.h @@ -17,7 +17,13 @@ struct msi_desc; struct pci_dev; struct platform_msi_priv_data; void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg); +#ifdef CONFIG_GENERIC_MSI_IRQ void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg); +#else +static inline void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg) +{ +} +#endif typedef void (*irq_write_msi_msg_t)(struct msi_desc *desc, struct msi_msg *msg); @@ -116,11 +122,15 @@ struct msi_desc { struct pci_dev *msi_desc_to_pci_dev(struct msi_desc *desc); void *msi_desc_to_pci_sysdata(struct msi_desc *desc); +void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg); #else /* CONFIG_PCI_MSI */ static inline void *msi_desc_to_pci_sysdata(struct msi_desc *desc) { return NULL; } +static inline void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg) +{ +} #endif /* CONFIG_PCI_MSI */ struct msi_desc *alloc_msi_entry(struct device *dev, int nvec, @@ -128,7 +138,6 @@ struct msi_desc *alloc_msi_entry(struct device *dev, int nvec, void free_msi_entry(struct msi_desc *entry); void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg); void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg); -void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg); u32 __pci_msix_desc_mask_irq(struct msi_desc *desc, u32 flag); u32 __pci_msi_desc_mask_irq(struct msi_desc *desc, u32 mask, u32 flag); -- 2.9.0
