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authorEugenio Pérez <eperezma@redhat.com>2022-03-14 18:34:41 +0100
committerJason Wang <jasowang@redhat.com>2022-03-15 13:57:44 +0800
commit10857ec0ad5d201d524d20b477da1cf3f7f4a3b0 (patch)
tree8d7965ac896df12e778ad684fb59179aae531a12
parentabe300d9d894f7138e1af7c8e9c88c04bfe98b37 (diff)
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vhost: Add VhostShadowVirtqueue
Vhost shadow virtqueue (SVQ) is an intermediate jump for virtqueue notifications and buffers, allowing qemu to track them. While qemu is forwarding the buffers and virtqueue changes, it is able to commit the memory it's being dirtied, the same way regular qemu's VirtIO devices do. This commit only exposes basic SVQ allocation and free. Next patches of the series add functionality like notifications and buffers forwarding. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
-rw-r--r--hw/virtio/meson.build2
-rw-r--r--hw/virtio/vhost-shadow-virtqueue.c62
-rw-r--r--hw/virtio/vhost-shadow-virtqueue.h28
3 files changed, 91 insertions, 1 deletions
diff --git a/hw/virtio/meson.build b/hw/virtio/meson.build
index 521f7d6..2dc8761 100644
--- a/hw/virtio/meson.build
+++ b/hw/virtio/meson.build
@@ -11,7 +11,7 @@ softmmu_ss.add(when: 'CONFIG_ALL', if_true: files('vhost-stub.c'))
virtio_ss = ss.source_set()
virtio_ss.add(files('virtio.c'))
-virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c'))
+virtio_ss.add(when: 'CONFIG_VHOST', if_true: files('vhost.c', 'vhost-backend.c', 'vhost-shadow-virtqueue.c'))
virtio_ss.add(when: 'CONFIG_VHOST_USER', if_true: files('vhost-user.c'))
virtio_ss.add(when: 'CONFIG_VHOST_VDPA', if_true: files('vhost-vdpa.c'))
virtio_ss.add(when: 'CONFIG_VIRTIO_BALLOON', if_true: files('virtio-balloon.c'))
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
new file mode 100644
index 0000000..c1db02c
--- /dev/null
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -0,0 +1,62 @@
+/*
+ * vhost shadow virtqueue
+ *
+ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
+ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "hw/virtio/vhost-shadow-virtqueue.h"
+
+#include "qemu/error-report.h"
+
+/**
+ * Creates vhost shadow virtqueue, and instructs the vhost device to use the
+ * shadow methods and file descriptors.
+ *
+ * Returns the new virtqueue or NULL.
+ *
+ * In case of error, reason is reported through error_report.
+ */
+VhostShadowVirtqueue *vhost_svq_new(void)
+{
+ g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
+ int r;
+
+ r = event_notifier_init(&svq->hdev_kick, 0);
+ if (r != 0) {
+ error_report("Couldn't create kick event notifier: %s (%d)",
+ g_strerror(errno), errno);
+ goto err_init_hdev_kick;
+ }
+
+ r = event_notifier_init(&svq->hdev_call, 0);
+ if (r != 0) {
+ error_report("Couldn't create call event notifier: %s (%d)",
+ g_strerror(errno), errno);
+ goto err_init_hdev_call;
+ }
+
+ return g_steal_pointer(&svq);
+
+err_init_hdev_call:
+ event_notifier_cleanup(&svq->hdev_kick);
+
+err_init_hdev_kick:
+ return NULL;
+}
+
+/**
+ * Free the resources of the shadow virtqueue.
+ *
+ * @pvq: gpointer to SVQ so it can be used by autofree functions.
+ */
+void vhost_svq_free(gpointer pvq)
+{
+ VhostShadowVirtqueue *vq = pvq;
+ event_notifier_cleanup(&vq->hdev_kick);
+ event_notifier_cleanup(&vq->hdev_call);
+ g_free(vq);
+}
diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
new file mode 100644
index 0000000..f1519e3
--- /dev/null
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -0,0 +1,28 @@
+/*
+ * vhost shadow virtqueue
+ *
+ * SPDX-FileCopyrightText: Red Hat, Inc. 2021
+ * SPDX-FileContributor: Author: Eugenio Pérez <eperezma@redhat.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef VHOST_SHADOW_VIRTQUEUE_H
+#define VHOST_SHADOW_VIRTQUEUE_H
+
+#include "qemu/event_notifier.h"
+
+/* Shadow virtqueue to relay notifications */
+typedef struct VhostShadowVirtqueue {
+ /* Shadow kick notifier, sent to vhost */
+ EventNotifier hdev_kick;
+ /* Shadow call notifier, sent to vhost */
+ EventNotifier hdev_call;
+} VhostShadowVirtqueue;
+
+VhostShadowVirtqueue *vhost_svq_new(void);
+
+void vhost_svq_free(gpointer vq);
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostShadowVirtqueue, vhost_svq_free);
+
+#endif