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, 9 insertions, 1 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 1d82b631d09c..6f7553684c1e 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2776,11 +2776,19 @@ static int amd_iommu_domain_has_cap(struct iommu_domain *domain,
 static int amd_iommu_device_group(struct device *dev, unsigned int *groupid)
 {
         struct iommu_dev_data *dev_data = dev->archdata.iommu;
+        struct pci_dev *pdev = to_pci_dev(dev);
+        u16 devid;
 
         if (!dev_data)
                 return -ENODEV;
 
-        *groupid = amd_iommu_alias_table[dev_data->devid];
+        if (pdev->is_virtfn || !iommu_group_mf)
+                devid = dev_data->devid;
+        else
+                devid = calc_devid(pdev->bus->number,
+                                   PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));
+
+        *groupid = amd_iommu_alias_table[devid];
 
         return 0;
 }