Re: [PATCH v4 4/5] hw/virtio: cleanup shared resources

[Manos Pitsidianakis <manos.pitsidianakis@linaro.org>]

On Mon, 19 Feb 2024 16:34, Albert Esteve <aesteve@redhat.com> wrote:
>Ensure that we cleanup all virtio shared
>resources when the vhost devices is cleaned
>up (after a hot unplug, or a crash).
>
>To do so, we add a new function to the virtio_dmabuf
>API called `virtio_dmabuf_vhost_cleanup`, which
>loop through the table and removes all
>resources owned by the vhost device parameter.
>
>Also, add a test to verify that the new
>function in the API behaves as expected.
>
>Signed-off-by: Albert Esteve <aesteve@redhat.com>
>Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
>---



Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>


> hw/display/virtio-dmabuf.c        | 21 ++++++++++++++++++++
> hw/virtio/vhost.c                 |  3 +++
> include/hw/virtio/virtio-dmabuf.h | 10 ++++++++++
> tests/unit/test-virtio-dmabuf.c   | 33 +++++++++++++++++++++++++++++++
> 4 files changed, 67 insertions(+)
>
>diff --git a/hw/display/virtio-dmabuf.c b/hw/display/virtio-dmabuf.c
>index 961094a561..703b5bd979 100644
>--- a/hw/display/virtio-dmabuf.c
>+++ b/hw/display/virtio-dmabuf.c
>@@ -141,6 +141,27 @@ SharedObjectType virtio_object_type(const QemuUUID *uuid)
>     return vso->type;
> }
> 
>+static bool virtio_dmabuf_resource_is_owned(gpointer key,
>+                                            gpointer value,
>+                                            gpointer dev)
>+{
>+    VirtioSharedObject *vso;
>+
>+    vso = (VirtioSharedObject *) value;
>+    return vso->type == TYPE_VHOST_DEV && vso->value.dev == dev;
>+}
>+
>+int virtio_dmabuf_vhost_cleanup(struct vhost_dev *dev)
>+{
>+    int num_removed;
>+
>+    WITH_QEMU_LOCK_GUARD(&lock) {
>+        num_removed = g_hash_table_foreach_remove(
>+            resource_uuids, (GHRFunc) virtio_dmabuf_resource_is_owned, dev);
>+    }
>+    return num_removed;
>+}
>+
> void virtio_free_resources(void)
> {
>     WITH_QEMU_LOCK_GUARD(&lock) {
>diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
>index 2c9ac79468..c5622eac14 100644
>--- a/hw/virtio/vhost.c
>+++ b/hw/virtio/vhost.c
>@@ -16,6 +16,7 @@
> #include "qemu/osdep.h"
> #include "qapi/error.h"
> #include "hw/virtio/vhost.h"
>+#include "hw/virtio/virtio-dmabuf.h"
> #include "qemu/atomic.h"
> #include "qemu/range.h"
> #include "qemu/error-report.h"
>@@ -1599,6 +1600,8 @@ void vhost_dev_cleanup(struct vhost_dev *hdev)
>     migrate_del_blocker(&hdev->migration_blocker);
>     g_free(hdev->mem);
>     g_free(hdev->mem_sections);
>+    /* free virtio shared objects */
>+    virtio_dmabuf_vhost_cleanup(hdev);
>     if (hdev->vhost_ops) {
>         hdev->vhost_ops->vhost_backend_cleanup(hdev);
>     }
>diff --git a/include/hw/virtio/virtio-dmabuf.h b/include/hw/virtio/virtio-dmabuf.h
>index 627d84dce9..950cd24967 100644
>--- a/include/hw/virtio/virtio-dmabuf.h
>+++ b/include/hw/virtio/virtio-dmabuf.h
>@@ -119,6 +119,16 @@ struct vhost_dev *virtio_lookup_vhost_device(const QemuUUID *uuid);
>  */
> SharedObjectType virtio_object_type(const QemuUUID *uuid);
> 
>+/**
>+ * virtio_dmabuf_vhost_cleanup() - Destroys all entries of the shared
>+ * resources lookup table that are owned by the vhost backend
>+ * @dev: the pointer to the vhost device that owns the entries. Data is owned
>+ *       by the called of the function.
>+ * 
>+ * Return: the number of resource entries removed.
>+ */
>+int virtio_dmabuf_vhost_cleanup(struct vhost_dev *dev);
>+
> /**
>  * virtio_free_resources() - Destroys all keys and values of the shared
>  * resources lookup table, and frees them
>diff --git a/tests/unit/test-virtio-dmabuf.c b/tests/unit/test-virtio-dmabuf.c
>index 20213455ee..e5cf7ee19f 100644
>--- a/tests/unit/test-virtio-dmabuf.c
>+++ b/tests/unit/test-virtio-dmabuf.c
>@@ -107,6 +107,38 @@ static void test_add_invalid_resource(void)
>     }
> }
> 
>+static void test_cleanup_res(void)
>+{
>+    QemuUUID uuids[20], uuid_alt;
>+    struct vhost_dev *dev = g_new0(struct vhost_dev, 1);
>+    struct vhost_dev *dev_alt = g_new0(struct vhost_dev, 1);
>+    int i, num_removed;
>+
>+    for (i = 0; i < ARRAY_SIZE(uuids); ++i) {
>+        qemu_uuid_generate(&uuids[i]);
>+        virtio_add_vhost_device(&uuids[i], dev);
>+        /* vhost device is found */
>+        g_assert(virtio_lookup_vhost_device(&uuids[i]) != NULL);
>+    }
>+    qemu_uuid_generate(&uuid_alt);
>+    virtio_add_vhost_device(&uuid_alt, dev_alt);
>+    /* vhost device is found */
>+    g_assert(virtio_lookup_vhost_device(&uuid_alt) != NULL);
>+    /* cleanup all dev resources */
>+    num_removed = virtio_dmabuf_vhost_cleanup(dev);
>+    g_assert_cmpint(num_removed, ==, ARRAY_SIZE(uuids));
>+    for (i = 0; i < ARRAY_SIZE(uuids); ++i) {
>+        /* None of the dev resources is found after free'd */
>+        g_assert_cmpint(virtio_lookup_dmabuf(&uuids[i]), ==, -1);
>+    }
>+    /* uuid_alt is still in the hash table */
>+    g_assert(virtio_lookup_vhost_device(&uuid_alt) != NULL);
>+
>+    virtio_free_resources();
>+    g_free(dev);
>+    g_free(dev_alt);
>+}
>+
> static void test_free_resources(void)
> {
>     QemuUUID uuids[20];
>@@ -136,6 +168,7 @@ int main(int argc, char **argv)
>                     test_remove_invalid_resource);
>     g_test_add_func("/virtio-dmabuf/add_invalid_res",
>                     test_add_invalid_resource);
>+    g_test_add_func("/virtio-dmabuf/cleanup_dev", test_cleanup_res);
>     g_test_add_func("/virtio-dmabuf/free_res", test_free_resources);
> 
>     return g_test_run();
>-- 
>2.43.1
>
>