3 files changed, 130 insertions, 0 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index edd291070b0..cce1f03b889 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3188,6 +3188,26 @@ static int amd_iommu_domain_has_cap(struct iommu_domain *domain,
         return 0;
 }
 
+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;
+
+        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;
+}
+
 static struct iommu_ops amd_iommu_ops = {
         .domain_init = amd_iommu_domain_init,
         .domain_destroy = amd_iommu_domain_destroy,
@@ -3197,6 +3217,7 @@ static struct iommu_ops amd_iommu_ops = {
         .unmap = amd_iommu_unmap,
         .iova_to_phys = amd_iommu_iova_to_phys,
         .domain_has_cap = amd_iommu_domain_has_cap,
+        .device_group = amd_iommu_device_group,
         .pgsize_bitmap  = AMD_IOMMU_PGSIZES,
 };
 
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index aea72e11e16..77e3b917c8d 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4080,6 +4080,54 @@ 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;
+                }
+        }
+
+        if (!pdev->is_virtfn && iommu_group_mf)
+                id.pci.devfn = PCI_DEVFN(PCI_SLOT(id.pci.devfn), 0);
+
+        *groupid = id.group;
+
+        return 0;
+}
+
 static struct iommu_ops intel_iommu_ops = {
         .domain_init    = intel_iommu_domain_init,
         .domain_destroy = intel_iommu_domain_destroy,
@@ -4089,6 +4137,7 @@ 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,
         .pgsize_bitmap  = INTEL_IOMMU_PGSIZES,
 };
 
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 14d6f908196..2198b2dbbcd 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -27,8 +27,59 @@
 #include <linux/errno.h>
 #include <linux/iommu.h>
 
+static ssize_t show_iommu_group(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+        unsigned int groupid;
+
+        if (iommu_device_group(dev, &groupid))
+                return 0;
+
+        return sprintf(buf, "%u", groupid);
+}
+static DEVICE_ATTR(iommu_group, S_IRUGO, show_iommu_group, NULL);
+
+static int add_iommu_group(struct device *dev, void *data)
+{
+        unsigned int groupid;
+
+        if (iommu_device_group(dev, &groupid) == 0)
+                return device_create_file(dev, &dev_attr_iommu_group);
+
+        return 0;
+}
+
+static int remove_iommu_group(struct device *dev)
+{
+        unsigned int groupid;
+
+        if (iommu_device_group(dev, &groupid) == 0)
+                device_remove_file(dev, &dev_attr_iommu_group);
+
+        return 0;
+}
+
+static int iommu_device_notifier(struct notifier_block *nb,
+                                 unsigned long action, void *data)
+{
+        struct device *dev = data;
+
+        if (action == BUS_NOTIFY_ADD_DEVICE)
+                return add_iommu_group(dev, NULL);
+        else if (action == BUS_NOTIFY_DEL_DEVICE)
+                return remove_iommu_group(dev);
+
+        return 0;
+}
+
+static struct notifier_block iommu_device_nb = {
+        .notifier_call = iommu_device_notifier,
+};
+
 static void iommu_bus_init(struct bus_type *bus, struct iommu_ops *ops)
 {
+        bus_register_notifier(bus, &iommu_device_nb);
+        bus_for_each_dev(bus, NULL, NULL, add_iommu_group);
 }
 
 /**
@@ -281,3 +332,12 @@ size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size)
         return unmapped;
 }
 EXPORT_SYMBOL_GPL(iommu_unmap);
+
+int iommu_device_group(struct device *dev, unsigned int *groupid)
+{
+        if (iommu_present(dev->bus) && dev->bus->iommu_ops->device_group)
+                return dev->bus->iommu_ops->device_group(dev, groupid);
+
+        return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(iommu_device_group);