iommu: Add option to group multi-function devices

The option iommu=group_mf indicates the that the iommu driver should
expose all functions of a multi-function PCI device as the same
iommu_device_group.  This is useful for disallowing individual functions
being exposed as independent devices to userspace as there are often
hidden dependencies.  Virtual functions are not affected by this option.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 39ca6bb17e13..9ef16d664a99 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4100,6 +4100,9 @@ static int intel_iommu_device_group(struct device *dev, unsigned int *groupid)
                 }
         }
 
+        if (!pdev->is_virtfn && iommu_group_mf)
+                id.pci.devfn = PCI_DEVFN(PCI_SLOT(id.pci.devfn), 0);
+
         *groupid = id.group;
 
         return 0;