iommu/intel: Implement iommu_device_group

We generally have BDF granularity for devices, so we just need
to make sure devices aren't hidden behind PCIe-to-PCI bridges.
We can then make up a group number that's simply the concatenated
seg|bus|dev|fn so we don't have to track them (not that users
should depend on that).

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

1 files changed, 46 insertions, 0 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index c0c7820d4c46..39ca6bb17e13 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4060,6 +4060,51 @@ static int intel_iommu_domain_has_cap(struct iommu_domain *domain,
         return 0;
 }
 
+/*
+ * Group numbers are arbitrary.  Device with the same group number
+ * indicate the iommu cannot differentiate between them.  To avoid
+ * tracking used groups we just use the seg|bus|devfn of the lowest
+ * level we're able to differentiate devices
+ */
+static int intel_iommu_device_group(struct device *dev, unsigned int *groupid)
+{
+        struct pci_dev *pdev = to_pci_dev(dev);
+        struct pci_dev *bridge;
+        union {
+                struct {
+                        u8 devfn;
+                        u8 bus;
+                        u16 segment;
+                } pci;
+                u32 group;
+        } id;
+
+        if (iommu_no_mapping(dev))
+                return -ENODEV;
+
+        id.pci.segment = pci_domain_nr(pdev->bus);
+        id.pci.bus = pdev->bus->number;
+        id.pci.devfn = pdev->devfn;
+
+        if (!device_to_iommu(id.pci.segment, id.pci.bus, id.pci.devfn))
+                return -ENODEV;
+
+        bridge = pci_find_upstream_pcie_bridge(pdev);
+        if (bridge) {
+                if (pci_is_pcie(bridge)) {
+                        id.pci.bus = bridge->subordinate->number;
+                        id.pci.devfn = 0;
+                } else {
+                        id.pci.bus = bridge->bus->number;
+                        id.pci.devfn = bridge->devfn;
+                }
+        }
+
+        *groupid = id.group;
+
+        return 0;
+}
+
 static struct iommu_ops intel_iommu_ops = {
         .domain_init    = intel_iommu_domain_init,
         .domain_destroy = intel_iommu_domain_destroy,
@@ -4069,6 +4114,7 @@ static struct iommu_ops intel_iommu_ops = {
         .unmap          = intel_iommu_unmap,
         .iova_to_phys   = intel_iommu_iova_to_phys,
         .domain_has_cap = intel_iommu_domain_has_cap,
+        .device_group   = intel_iommu_device_group,
 };
 
 static void __devinit quirk_iommu_rwbf(struct pci_dev *dev)