iommu/vt-d: Report domain usage in sysfs

Debugging domain ID leakage typically requires long running tests in
order to exhaust the domain ID space or kernel instrumentation to
track the setting and clearing of bits.  A couple trivial intel-iommu
specific sysfs extensions make it much easier to expose the IOMMU
capabilities and current usage.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0be23c589d3b31263f3685b80cfeb933ac414a85..013cbc2005797058e0388f8d59eeadbd6e176de5 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4449,11 +4449,32 @@ static ssize_t intel_iommu_show_ecap(struct device *dev,
 }
 static DEVICE_ATTR(ecap, S_IRUGO, intel_iommu_show_ecap, NULL);
 
+static ssize_t intel_iommu_show_ndoms(struct device *dev,
+                                     struct device_attribute *attr,
+                                     char *buf)
+{
+       struct intel_iommu *iommu = dev_get_drvdata(dev);
+       return sprintf(buf, "%ld\n", cap_ndoms(iommu->cap));
+}
+static DEVICE_ATTR(domains_supported, S_IRUGO, intel_iommu_show_ndoms, NULL);
+
+static ssize_t intel_iommu_show_ndoms_used(struct device *dev,
+                                          struct device_attribute *attr,
+                                          char *buf)
+{
+       struct intel_iommu *iommu = dev_get_drvdata(dev);
+       return sprintf(buf, "%d\n", bitmap_weight(iommu->domain_ids,
+                                                 cap_ndoms(iommu->cap)));
+}
+static DEVICE_ATTR(domains_used, S_IRUGO, intel_iommu_show_ndoms_used, NULL);
+
 static struct attribute *intel_iommu_attrs[] = {
        &dev_attr_version.attr,
        &dev_attr_address.attr,
        &dev_attr_cap.attr,
        &dev_attr_ecap.attr,
+       &dev_attr_domains_supported.attr,
+       &dev_attr_domains_used.attr,
        NULL,
 };