[PATCH v2 06/14] vdpa: adapt vhost_ops callbacks to svq

["Eugenio Pérez" <eperezma@redhat.com>]

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-vdpa.c | 84 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 73 insertions(+), 11 deletions(-)

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index d614c435f3..b2c4e92fcf 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -344,6 +344,16 @@ static bool vhost_vdpa_one_time_request(struct vhost_dev *dev)
     return v->index != 0;
 }
 
+static int vhost_vdpa_get_dev_features(struct vhost_dev *dev,
+                                       uint64_t *features)
+{
+    int ret;
+
+    ret = vhost_vdpa_call(dev, VHOST_GET_FEATURES, features);
+    trace_vhost_vdpa_get_features(dev, *features);
+    return ret;
+}
+
 static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
                                Error **errp)
 {
@@ -356,7 +366,7 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
         return 0;
     }
 
-    r = hdev->vhost_ops->vhost_get_features(hdev, &dev_features);
+    r = vhost_vdpa_get_dev_features(hdev, &dev_features);
     if (r != 0) {
         error_setg_errno(errp, -r, "Can't get vdpa device features");
         return r;
@@ -583,12 +593,26 @@ static int vhost_vdpa_set_mem_table(struct vhost_dev *dev,
 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 features_ok = features;
+        bool ok;
+
+        ok = vhost_svq_valid_features(&features_ok);
+        if (unlikely(!ok)) {
+            error_report(
+                "Invalid guest acked feature flag, acked: 0x%"
+                PRIx64", ok: 0x%"PRIx64, features, features_ok);
+            return -EINVAL;
+        }
+    }
+
     trace_vhost_vdpa_set_features(dev, features);
     ret = vhost_vdpa_call(dev, VHOST_SET_FEATURES, &features);
     if (ret) {
@@ -735,6 +759,13 @@ static int vhost_vdpa_get_config(struct vhost_dev *dev, uint8_t *config,
     return ret;
  }
 
+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_dev_kick(struct vhost_dev *dev,
                                          struct vhost_vring_file *file)
 {
@@ -749,6 +780,18 @@ static int vhost_vdpa_set_vring_dev_call(struct vhost_dev *dev,
     return vhost_vdpa_call(dev, VHOST_SET_VRING_CALL, file);
 }
 
+static int vhost_vdpa_set_vring_dev_addr(struct vhost_dev *dev,
+                                         struct vhost_vring_addr *addr)
+{
+    trace_vhost_vdpa_set_vring_addr(dev, addr->index, addr->flags,
+                                addr->desc_user_addr, addr->used_user_addr,
+                                addr->avail_user_addr,
+                                addr->log_guest_addr);
+
+    return vhost_vdpa_call(dev, VHOST_SET_VRING_ADDR, addr);
+
+}
+
 /**
  * Set the shadow virtqueue descriptors to the device
  *
@@ -859,11 +902,17 @@ static int vhost_vdpa_set_log_base(struct vhost_dev *dev, uint64_t base,
 static int vhost_vdpa_set_vring_addr(struct vhost_dev *dev,
                                        struct vhost_vring_addr *addr)
 {
-    trace_vhost_vdpa_set_vring_addr(dev, addr->index, addr->flags,
-                                    addr->desc_user_addr, addr->used_user_addr,
-                                    addr->avail_user_addr,
-                                    addr->log_guest_addr);
-    return vhost_vdpa_call(dev, VHOST_SET_VRING_ADDR, addr);
+    struct vhost_vdpa *v = dev->opaque;
+
+    if (v->shadow_vqs_enabled) {
+        /*
+         * Device vring addr was set at device start. SVQ base is handled by
+         * VirtQueue code.
+         */
+        return 0;
+    }
+
+    return vhost_vdpa_set_vring_dev_addr(dev, addr);
 }
 
 static int vhost_vdpa_set_vring_num(struct vhost_dev *dev,
@@ -876,8 +925,17 @@ static int vhost_vdpa_set_vring_num(struct vhost_dev *dev,
 static int vhost_vdpa_set_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);
+    struct vhost_vdpa *v = dev->opaque;
+
+    if (v->shadow_vqs_enabled) {
+        /*
+         * Device 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,
@@ -924,10 +982,14 @@ static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,
 static int vhost_vdpa_get_features(struct vhost_dev *dev,
                                      uint64_t *features)
 {
-    int ret;
+    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_features(features);
+    }
 
-    ret = vhost_vdpa_call(dev, VHOST_GET_FEATURES, features);
-    trace_vhost_vdpa_get_features(dev, *features);
     return ret;
 }
 
-- 
2.27.0