[PATCH 17/31] vdpa: adapt vhost_ops callbacks to svq

[Eugenio Pérez]

First half of the buffers forwarding part, preparing vhost-vdpa
callbacks to SVQ to offer it. QEMU cannot enable it at this moment, so
this is effectively dead code at the moment, but it helps to reduce
patch size.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h |   2 +-
 hw/virtio/vhost-shadow-virtqueue.c |  21 ++++-
 hw/virtio/vhost-vdpa.c             | 133 ++++++++++++++++++++++++++---
 3 files changed, 143 insertions(+), 13 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h 
b/hw/virtio/vhost-shadow-virtqueue.h
index 035207a469..39aef5ffdf 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -35,7 +35,7 @@ size_t vhost_svq_device_area_size(const VhostShadowVirtqueue 
*svq);
 
 void vhost_svq_stop(VhostShadowVirtqueue *svq);
 
-VhostShadowVirtqueue *vhost_svq_new(void);
+VhostShadowVirtqueue *vhost_svq_new(uint16_t qsize);
 
 void vhost_svq_free(VhostShadowVirtqueue *vq);
 
diff --git a/hw/virtio/vhost-shadow-virtqueue.c 
b/hw/virtio/vhost-shadow-virtqueue.c
index f129ec8395..7c168075d7 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -277,9 +277,17 @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
 /**
  * Creates vhost shadow virtqueue, and instruct vhost device to use the shadow
  * methods and file descriptors.
+ *
+ * @qsize Shadow VirtQueue size
+ *
+ * Returns the new virtqueue or NULL.
+ *
+ * In case of error, reason is reported through error_report.
  */
-VhostShadowVirtqueue *vhost_svq_new(void)
+VhostShadowVirtqueue *vhost_svq_new(uint16_t qsize)
 {
+    size_t desc_size = sizeof(vring_desc_t) * qsize;
+    size_t device_size, driver_size;
     g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
     int r;
 
@@ -300,6 +308,15 @@ VhostShadowVirtqueue *vhost_svq_new(void)
     /* Placeholder descriptor, it should be deleted at set_kick_fd */
     event_notifier_init_fd(&svq->svq_kick, INVALID_SVQ_KICK_FD);
 
+    svq->vring.num = qsize;
+    driver_size = vhost_svq_driver_area_size(svq);
+    device_size = vhost_svq_device_area_size(svq);
+    svq->vring.desc = qemu_memalign(qemu_real_host_page_size, driver_size);
+    svq->vring.avail = (void *)((char *)svq->vring.desc + desc_size);
+    memset(svq->vring.desc, 0, driver_size);
+    svq->vring.used = qemu_memalign(qemu_real_host_page_size, device_size);
+    memset(svq->vring.used, 0, device_size);
+
     event_notifier_set_handler(&svq->hdev_call, vhost_svq_handle_call);
     return g_steal_pointer(&svq);
 
@@ -318,5 +335,7 @@ void vhost_svq_free(VhostShadowVirtqueue *vq)
     event_notifier_cleanup(&vq->hdev_kick);
     event_notifier_set_handler(&vq->hdev_call, NULL);
     event_notifier_cleanup(&vq->hdev_call);
+    qemu_vfree(vq->vring.desc);
+    qemu_vfree(vq->vring.used);
     g_free(vq);
 }
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 9d801cf907..53e14bafa0 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -641,20 +641,52 @@ static int vhost_vdpa_set_vring_addr(struct vhost_dev 
*dev,
     return vhost_vdpa_call(dev, VHOST_SET_VRING_ADDR, addr);
 }
 
-static int vhost_vdpa_set_vring_num(struct vhost_dev *dev,
-                                      struct vhost_vring_state *ring)
+static int vhost_vdpa_set_dev_vring_num(struct vhost_dev *dev,
+                                        struct vhost_vring_state *ring)
 {
     trace_vhost_vdpa_set_vring_num(dev, ring->index, ring->num);
     return vhost_vdpa_call(dev, VHOST_SET_VRING_NUM, ring);
 }
 
-static int vhost_vdpa_set_vring_base(struct vhost_dev *dev,
-                                       struct vhost_vring_state *ring)
+static int vhost_vdpa_set_vring_num(struct vhost_dev *dev,
+                                    struct vhost_vring_state *ring)
+{
+    struct vhost_vdpa *v = dev->opaque;
+
+    if (v->shadow_vqs_enabled) {
+        /*
+         * Vring num was set at device start. SVQ num is handled by VirtQueue
+         * code
+         */
+        return 0;
+    }
+
+    return vhost_vdpa_set_dev_vring_num(dev, ring);
+}
+
+static int vhost_vdpa_set_dev_vring_base(struct vhost_dev *dev,
+                                         struct vhost_vring_state *ring)
 {
     trace_vhost_vdpa_set_vring_base(dev, ring->index, ring->num);
     return vhost_vdpa_call(dev, VHOST_SET_VRING_BASE, ring);
 }
 
+static int vhost_vdpa_set_vring_base(struct vhost_dev *dev,
+                                     struct vhost_vring_state *ring)
+{
+    struct vhost_vdpa *v = dev->opaque;
+
+    if (v->shadow_vqs_enabled) {
+        /*
+         * Vring base was set at device start. SVQ base is handled by VirtQueue
+         * code
+         */
+        return 0;
+    }
+
+    return vhost_vdpa_set_dev_vring_base(dev, ring);
+}
+
 static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
                                        struct vhost_vring_state *ring)
 {
@@ -784,8 +816,8 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool 
started)
     }
 }
 
-static int vhost_vdpa_get_features(struct vhost_dev *dev,
-                                     uint64_t *features)
+static int vhost_vdpa_get_dev_features(struct vhost_dev *dev,
+                                       uint64_t *features)
 {
     int ret;
 
@@ -794,15 +826,64 @@ static int vhost_vdpa_get_features(struct vhost_dev *dev,
     return ret;
 }
 
+static int vhost_vdpa_get_features(struct vhost_dev *dev, uint64_t *features)
+{
+    struct vhost_vdpa *v = dev->opaque;
+    int ret = vhost_vdpa_get_dev_features(dev, features);
+
+    if (ret == 0 && v->shadow_vqs_enabled) {
+        /* Filter only features that SVQ can offer to guest */
+        vhost_svq_valid_guest_features(features);
+    }
+
+    return ret;
+}
+
 static int vhost_vdpa_set_features(struct vhost_dev *dev,
                                    uint64_t features)
 {
+    struct vhost_vdpa *v = dev->opaque;
     int ret;
 
     if (vhost_vdpa_one_time_request(dev)) {
         return 0;
     }
 
+    if (v->shadow_vqs_enabled) {
+        uint64_t dev_features, svq_features, acked_features;
+        bool ok;
+
+        ret = vhost_vdpa_get_dev_features(dev, &dev_features);
+        if (ret != 0) {
+            error_report("Can't get vdpa device features, got (%d)", ret);
+            return ret;
+        }
+
+        svq_features = dev_features;
+        ok = vhost_svq_valid_device_features(&svq_features);
+        if (unlikely(!ok)) {
+            error_report("SVQ Invalid device feature flags, offer: 0x%"
+                         PRIx64", ok: 0x%"PRIx64, dev->features, svq_features);
+            return -1;
+        }
+
+        ok = vhost_svq_valid_guest_features(&features);
+        if (unlikely(!ok)) {
+            error_report(
+                "Invalid guest acked feature flag, acked: 0x%"
+                PRIx64", ok: 0x%"PRIx64, dev->acked_features, features);
+            return -1;
+        }
+
+        ok = vhost_svq_ack_guest_features(svq_features, features,
+                                          &acked_features);
+        if (unlikely(!ok)) {
+            return -1;
+        }
+
+        features = acked_features;
+    }
+
     trace_vhost_vdpa_set_features(dev, features);
     ret = vhost_vdpa_call(dev, VHOST_SET_FEATURES, &features);
     if (ret) {
@@ -822,13 +903,31 @@ static int vhost_vdpa_set_owner(struct vhost_dev *dev)
     return vhost_vdpa_call(dev, VHOST_SET_OWNER, NULL);
 }
 
-static int vhost_vdpa_vq_get_addr(struct vhost_dev *dev,
-                    struct vhost_vring_addr *addr, struct vhost_virtqueue *vq)
+static void vhost_vdpa_vq_get_guest_addr(struct vhost_vring_addr *addr,
+                                         struct vhost_virtqueue *vq)
 {
-    assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
     addr->desc_user_addr = (uint64_t)(unsigned long)vq->desc_phys;
     addr->avail_user_addr = (uint64_t)(unsigned long)vq->avail_phys;
     addr->used_user_addr = (uint64_t)(unsigned long)vq->used_phys;
+}
+
+static int vhost_vdpa_vq_get_addr(struct vhost_dev *dev,
+                                  struct vhost_vring_addr *addr,
+                                  struct vhost_virtqueue *vq)
+{
+    struct vhost_vdpa *v = dev->opaque;
+
+    assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_VDPA);
+
+    if (v->shadow_vqs_enabled) {
+        int idx = vhost_vdpa_get_vq_index(dev, addr->index);
+        VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, idx);
+
+        vhost_svq_get_vring_addr(svq, addr);
+    } else {
+        vhost_vdpa_vq_get_guest_addr(addr, vq);
+    }
+
     trace_vhost_vdpa_vq_get_addr(dev, vq, addr->desc_user_addr,
                                  addr->avail_user_addr, addr->used_user_addr);
     return 0;
@@ -849,6 +948,12 @@ static void vhost_psvq_free(gpointer svq)
     vhost_svq_free(svq);
 }
 
+static int vhost_vdpa_get_max_queue_size(struct vhost_dev *dev,
+                                         uint16_t *qsize)
+{
+    return vhost_vdpa_call(dev, VHOST_VDPA_GET_VRING_NUM, qsize);
+}
+
 static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
                                Error **errp)
 {
@@ -857,6 +962,7 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, 
struct vhost_vdpa *v,
                                                            vhost_psvq_free);
     uint64_t dev_features;
     uint64_t svq_features;
+    uint16_t qsize;
     int r;
     bool ok;
 
@@ -864,7 +970,7 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, 
struct vhost_vdpa *v,
         goto out;
     }
 
-    r = vhost_vdpa_get_features(hdev, &dev_features);
+    r = vhost_vdpa_get_dev_features(hdev, &dev_features);
     if (r != 0) {
         error_setg(errp, "Can't get vdpa device features, got (%d)", r);
         return r;
@@ -879,9 +985,14 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, 
struct vhost_vdpa *v,
         return -1;
     }
 
+    r = vhost_vdpa_get_max_queue_size(hdev, &qsize);
+    if (unlikely(r)) {
+        qsize = 256;
+    }
+
     shadow_vqs = g_ptr_array_new_full(hdev->nvqs, vhost_psvq_free);
     for (unsigned n = 0; n < hdev->nvqs; ++n) {
-        VhostShadowVirtqueue *svq = vhost_svq_new();
+        VhostShadowVirtqueue *svq = vhost_svq_new(qsize);
 
         if (unlikely(!svq)) {
             error_setg(errp, "Cannot create svq %u", n);
-- 
2.27.0