xen/iommu: Introduce iommu_remove_dt_device()

Remove master device from the IOMMU. This will be helpful when removing the
overlay nodes using dynamic programming during run time.

Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>

diff --git a/xen/drivers/passthrough/device_tree.c b/xen/drivers/passthrough/device_tree.c
index 687c61e7dad8c45c57996a1ac8e5559e96aec683..80f6efc606ca8da08345624dde7bcd38e484863e 100644 (file)
--- a/xen/drivers/passthrough/device_tree.c
+++ b/xen/drivers/passthrough/device_tree.c
@@ -127,6 +127,49 @@ int iommu_release_dt_devices(struct domain *d)
     return 0;
 }
 
+int iommu_remove_dt_device(struct dt_device_node *np)
+{
+    const struct iommu_ops *ops = iommu_get_ops();
+    struct device *dev = dt_to_dev(np);
+    int rc;
+
+    if ( !iommu_enabled )
+        return 1;
+
+    if ( !ops )
+        return -EOPNOTSUPP;
+
+    spin_lock(&dtdevs_lock);
+
+    if ( iommu_dt_device_is_assigned_locked(np) )
+    {
+        rc = -EBUSY;
+        goto fail;
+    }
+
+    if ( !ops->remove_device )
+    {
+        rc = -EOPNOTSUPP;
+        goto fail;
+    }
+
+    /*
+     * De-register the device from the IOMMU driver.
+     * The driver is responsible for removing is_protected flag.
+     */
+    rc = ops->remove_device(0, dev);
+
+    if ( !rc )
+    {
+        ASSERT(!dt_device_is_protected(np));
+        iommu_fwspec_free(dev);
+    }
+
+ fail:
+    spin_unlock(&dtdevs_lock);
+    return rc;
+}
+
 int iommu_add_dt_device(struct dt_device_node *np)
 {
     const struct iommu_ops *ops = iommu_get_ops();

diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index a18b68e24756c1f61b6c7b7166f9bb2d3251ac11..0e747b0bbc1c334537666770a6f99ee9de596b37 100644 (file)
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -235,6 +235,16 @@ int iommu_add_dt_device(struct dt_device_node *np);
 int iommu_do_dt_domctl(struct xen_domctl *domctl, struct domain *d,
                        XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl);
 
+/*
+ * Helper to remove master device from the IOMMU.
+ *
+ * Return values:
+ *  0 : device is de-registered from IOMMU.
+ * <0 : error while removing the device from IOMMU.
+ * >0 : IOMMU is not enabled/present.
+ */
+int iommu_remove_dt_device(struct dt_device_node *np);
+
 #endif /* HAS_DEVICE_TREE */
 
 struct page_info;