diff options
Diffstat (limited to 'drivers/pci/controller/vmd.c')
| -rw-r--r-- | drivers/pci/controller/vmd.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c index 9d9596947350..e619accca49d 100644 --- a/drivers/pci/controller/vmd.c +++ b/drivers/pci/controller/vmd.c @@ -17,6 +17,8 @@ #include <linux/rculist.h> #include <linux/rcupdate.h> +#include <xen/xen.h> + #include <asm/irqdomain.h> #define VMD_CFGBAR 0 @@ -970,6 +972,24 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id) struct vmd_dev *vmd; int err; + if (xen_domain()) { + /* + * Xen doesn't have knowledge about devices in the VMD bus + * because the config space of devices behind the VMD bridge is + * not known to Xen, and hence Xen cannot discover or configure + * them in any way. + * + * Bypass of MSI remapping won't work in that case as direct + * write by Linux to the MSI entries won't result in functional + * interrupts, as Xen is the entity that manages the host + * interrupt controller and must configure interrupts. However + * multiplexing of interrupts by the VMD bridge will work under + * Xen, so force the usage of that mode which must always be + * supported by VMD bridges. + */ + features &= ~VMD_FEAT_CAN_BYPASS_MSI_REMAP; + } + if (resource_size(&dev->resource[VMD_CFGBAR]) < (1 << 20)) return -ENOMEM; |