[PATCH v12 06/13] virtio-iommu: Implement attach/detach command

[Eric Auger]

This patch implements the endpoint attach/detach to/from
a domain.

Signed-off-by: Eric Auger <eric.au...@redhat.com>

---

v11 -> v12:
- check the device is protected by the iommu on attach
- on detach, check the domain id the device is attached to matches
  the one used in the detach command
- fix mapping ref counter and destroy the domain when no end-points
  are attached anymore
---
 hw/virtio/virtio-iommu.c | 65 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 58 insertions(+), 7 deletions(-)

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 6a03c3d7ae..63b2d30f28 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -119,11 +119,12 @@ static gint interval_cmp(gconstpointer a, gconstpointer 
b, gpointer user_data)
 static void virtio_iommu_detach_endpoint_from_domain(VirtIOIOMMUEndpoint *ep)
 {
     QLIST_REMOVE(ep, next);
+    g_tree_unref(ep->domain->mappings);
     ep->domain = NULL;
 }
 
-VirtIOIOMMUEndpoint *virtio_iommu_get_endpoint(VirtIOIOMMU *s, uint32_t ep_id);
-VirtIOIOMMUEndpoint *virtio_iommu_get_endpoint(VirtIOIOMMU *s, uint32_t ep_id)
+static VirtIOIOMMUEndpoint *virtio_iommu_get_endpoint(VirtIOIOMMU *s,
+                                                      uint32_t ep_id)
 {
     VirtIOIOMMUEndpoint *ep;
 
@@ -151,8 +152,8 @@ static void virtio_iommu_put_endpoint(gpointer data)
     g_free(ep);
 }
 
-VirtIOIOMMUDomain *virtio_iommu_get_domain(VirtIOIOMMU *s, uint32_t domain_id);
-VirtIOIOMMUDomain *virtio_iommu_get_domain(VirtIOIOMMU *s, uint32_t domain_id)
+static VirtIOIOMMUDomain *virtio_iommu_get_domain(VirtIOIOMMU *s,
+                                                  uint32_t domain_id)
 {
     VirtIOIOMMUDomain *domain;
 
@@ -179,7 +180,6 @@ static void virtio_iommu_put_domain(gpointer data)
     QLIST_FOREACH_SAFE(iter, &domain->endpoint_list, next, tmp) {
         virtio_iommu_detach_endpoint_from_domain(iter);
     }
-    g_tree_destroy(domain->mappings);
     trace_virtio_iommu_put_domain(domain->id);
     g_free(domain);
 }
@@ -228,10 +228,37 @@ static int virtio_iommu_attach(VirtIOIOMMU *s,
 {
     uint32_t domain_id = le32_to_cpu(req->domain);
     uint32_t ep_id = le32_to_cpu(req->endpoint);
+    VirtIOIOMMUDomain *domain;
+    VirtIOIOMMUEndpoint *ep;
 
     trace_virtio_iommu_attach(domain_id, ep_id);
 
-    return VIRTIO_IOMMU_S_UNSUPP;
+    ep = virtio_iommu_get_endpoint(s, ep_id);
+    if (!ep) {
+        return VIRTIO_IOMMU_S_NOENT;
+    }
+
+    if (ep->domain) {
+        VirtIOIOMMUDomain *previous_domain = ep->domain;
+        /*
+         * the device is already attached to a domain,
+         * detach it first
+         */
+        virtio_iommu_detach_endpoint_from_domain(ep);
+        if (QLIST_EMPTY(&previous_domain->endpoint_list)) {
+            g_tree_remove(s->domains, GUINT_TO_POINTER(previous_domain->id));
+        }
+    }
+
+    domain = virtio_iommu_get_domain(s, domain_id);
+    if (!QLIST_EMPTY(&domain->endpoint_list)) {
+        g_tree_ref(domain->mappings);
+    }
+    QLIST_INSERT_HEAD(&domain->endpoint_list, ep, next);
+
+    ep->domain = domain;
+
+    return VIRTIO_IOMMU_S_OK;
 }
 
 static int virtio_iommu_detach(VirtIOIOMMU *s,
@@ -239,10 +266,34 @@ static int virtio_iommu_detach(VirtIOIOMMU *s,
 {
     uint32_t domain_id = le32_to_cpu(req->domain);
     uint32_t ep_id = le32_to_cpu(req->endpoint);
+    VirtIOIOMMUDomain *domain;
+    VirtIOIOMMUEndpoint *ep;
 
     trace_virtio_iommu_detach(domain_id, ep_id);
 
-    return VIRTIO_IOMMU_S_UNSUPP;
+    ep = g_tree_lookup(s->endpoints, GUINT_TO_POINTER(ep_id));
+    if (!ep) {
+        return VIRTIO_IOMMU_S_NOENT;
+    }
+
+    domain = ep->domain;
+
+    if (!domain || domain->id != domain_id) {
+        return VIRTIO_IOMMU_S_INVAL;
+    }
+
+    virtio_iommu_detach_endpoint_from_domain(ep);
+
+    /*
+     * when the last EP is detached, simply remove the domain for
+     * the domain list and destroy it. Note its mappings were already
+     * freed by the ref count mechanism. Next operation involving
+     * the same domain id will re-create one domain object.
+     */
+    if (QLIST_EMPTY(&domain->endpoint_list)) {
+        g_tree_remove(s->domains, GUINT_TO_POINTER(domain->id));
+    }
+    return VIRTIO_IOMMU_S_OK;
 }
 
 static int virtio_iommu_map(VirtIOIOMMU *s,
-- 
2.20.1