iommu: Add max_pasids field in struct dev_iommu

Use this field to save the number of PASIDs that a device is able to
consume. It is a generic attribute of a device and lifting it into the
per-device dev_iommu struct could help to avoid the boilerplate code
in various IOMMU drivers.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Tested-by: Tony Zhu <tony.zhu@intel.com>
Link: https://lore.kernel.org/r/20221031005917.45690-3-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 65a3b3d..297ac79 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -21,6 +21,7 @@
 #include <linux/idr.h>
 #include <linux/err.h>
 #include <linux/pci.h>
+#include <linux/pci-ats.h>
 #include <linux/bitops.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
@@ -278,6 +279,24 @@ static void dev_iommu_free(struct device *dev)
        kfree(param);
 }
 
+static u32 dev_iommu_get_max_pasids(struct device *dev)
+{
+       u32 max_pasids = 0, bits = 0;
+       int ret;
+
+       if (dev_is_pci(dev)) {
+               ret = pci_max_pasids(to_pci_dev(dev));
+               if (ret > 0)
+                       max_pasids = ret;
+       } else {
+               ret = device_property_read_u32(dev, "pasid-num-bits", &bits);
+               if (!ret)
+                       max_pasids = 1UL << bits;
+       }
+
+       return min_t(u32, max_pasids, dev->iommu->iommu_dev->max_pasids);
+}
+
 static int __iommu_probe_device(struct device *dev, struct list_head *group_list)
 {
        const struct iommu_ops *ops = dev->bus->iommu_ops;
@@ -303,6 +322,7 @@ static int __iommu_probe_device(struct device *dev, struct list_head *group_list
        }
 
        dev->iommu->iommu_dev = iommu_dev;
+       dev->iommu->max_pasids = dev_iommu_get_max_pasids(dev);
 
        group = iommu_group_get_for_dev(dev);
        if (IS_ERR(group)) {

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index e3af4f4..ac3f6c6 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -368,6 +368,7 @@ struct iommu_fault_param {
  * @fwspec:     IOMMU fwspec data
  * @iommu_dev:  IOMMU device this device is linked to
  * @priv:       IOMMU Driver private data
+ * @max_pasids:  number of PASIDs this device can consume
  *
  * TODO: migrate other per device data pointers under iommu_dev_data, e.g.
  *     struct iommu_group      *iommu_group;
@@ -379,6 +380,7 @@ struct dev_iommu {
        struct iommu_fwspec             *fwspec;
        struct iommu_device             *iommu_dev;
        void                            *priv;
+       u32                             max_pasids;
 };
 
 int iommu_device_register(struct iommu_device *iommu,