net: Consolidate vhost feature bits into vhost_net structure

Previously, the vhost_net_get_feature_bits() function in
hw/net/vhost_net.c used a large switch statement to determine
the appropriate feature bits based on the NetClientDriver type.

This created unnecessary coupling between the generic vhost layer
and specific network backends (like TAP, vhost-user, and
vhost-vdpa).

This patch moves the definition of vhost feature bits directly into the
vhost_net structure for each relevant network client.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

7 files changed, 69 insertions, 90 deletions

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index db8b97b..787c769 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -36,94 +36,9 @@
 #include "hw/virtio/virtio-bus.h"
 #include "linux-headers/linux/vhost.h"
 
-
-/* Features supported by host kernel. */
-static const int kernel_feature_bits[] = {
-    VIRTIO_F_NOTIFY_ON_EMPTY,
-    VIRTIO_RING_F_INDIRECT_DESC,
-    VIRTIO_RING_F_EVENT_IDX,
-    VIRTIO_NET_F_MRG_RXBUF,
-    VIRTIO_F_VERSION_1,
-    VIRTIO_NET_F_MTU,
-    VIRTIO_F_IOMMU_PLATFORM,
-    VIRTIO_F_RING_PACKED,
-    VIRTIO_F_RING_RESET,
-    VIRTIO_F_IN_ORDER,
-    VIRTIO_F_NOTIFICATION_DATA,
-    VIRTIO_NET_F_RSC_EXT,
-    VIRTIO_NET_F_HASH_REPORT,
-    VHOST_INVALID_FEATURE_BIT
-};
-
-/* Features supported by others. */
-static const int user_feature_bits[] = {
-    VIRTIO_F_NOTIFY_ON_EMPTY,
-    VIRTIO_F_NOTIFICATION_DATA,
-    VIRTIO_RING_F_INDIRECT_DESC,
-    VIRTIO_RING_F_EVENT_IDX,
-
-    VIRTIO_F_ANY_LAYOUT,
-    VIRTIO_F_VERSION_1,
-    VIRTIO_NET_F_CSUM,
-    VIRTIO_NET_F_GUEST_CSUM,
-    VIRTIO_NET_F_GSO,
-    VIRTIO_NET_F_GUEST_TSO4,
-    VIRTIO_NET_F_GUEST_TSO6,
-    VIRTIO_NET_F_GUEST_ECN,
-    VIRTIO_NET_F_GUEST_UFO,
-    VIRTIO_NET_F_HOST_TSO4,
-    VIRTIO_NET_F_HOST_TSO6,
-    VIRTIO_NET_F_HOST_ECN,
-    VIRTIO_NET_F_HOST_UFO,
-    VIRTIO_NET_F_MRG_RXBUF,
-    VIRTIO_NET_F_MTU,
-    VIRTIO_F_IOMMU_PLATFORM,
-    VIRTIO_F_RING_PACKED,
-    VIRTIO_F_RING_RESET,
-    VIRTIO_F_IN_ORDER,
-    VIRTIO_NET_F_RSS,
-    VIRTIO_NET_F_RSC_EXT,
-    VIRTIO_NET_F_HASH_REPORT,
-    VIRTIO_NET_F_GUEST_USO4,
-    VIRTIO_NET_F_GUEST_USO6,
-    VIRTIO_NET_F_HOST_USO,
-
-    /* This bit implies RARP isn't sent by QEMU out of band */
-    VIRTIO_NET_F_GUEST_ANNOUNCE,
-
-    VIRTIO_NET_F_MQ,
-
-    VHOST_INVALID_FEATURE_BIT
-};
-
-static const int *vhost_net_get_feature_bits(struct vhost_net *net)
-{
-    const int *feature_bits = 0;
-
-    switch (net->nc->info->type) {
-    case NET_CLIENT_DRIVER_TAP:
-        feature_bits = kernel_feature_bits;
-        break;
-    case NET_CLIENT_DRIVER_VHOST_USER:
-        feature_bits = user_feature_bits;
-        break;
-#ifdef CONFIG_VHOST_NET_VDPA
-    case NET_CLIENT_DRIVER_VHOST_VDPA:
-        feature_bits = vdpa_feature_bits;
-        break;
-#endif
-    default:
-        error_report("Feature bits not defined for this type: %d",
-                net->nc->info->type);
-        break;
-    }
-
-    return feature_bits;
-}
-
 uint64_t vhost_net_get_features(struct vhost_net *net, uint64_t features)
 {
-    return vhost_get_features(&net->dev, vhost_net_get_feature_bits(net),
+    return vhost_get_features(&net->dev, net->feature_bits,
             features);
 }
 int vhost_net_get_config(struct vhost_net *net,  uint8_t *config,
@@ -140,7 +55,7 @@ int vhost_net_set_config(struct vhost_net *net, const uint8_t *data,
 void vhost_net_ack_features(struct vhost_net *net, uint64_t features)
 {
     net->dev.acked_features = net->dev.backend_features;
-    vhost_ack_features(&net->dev, vhost_net_get_feature_bits(net), features);
+    vhost_ack_features(&net->dev, net->feature_bits, features);
 }
 
 uint64_t vhost_net_get_max_queues(VHostNetState *net)
@@ -329,6 +244,7 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
     }
     net->nc = options->net_backend;
     net->dev.nvqs = options->nvqs;
+    net->feature_bits = options->feature_bits;
 
     net->dev.max_queues = 1;
     net->dev.vqs = net->vqs;
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index 38800a7..6a75fdc 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -143,6 +143,7 @@ struct vhost_net {
     struct vhost_dev dev;
     struct vhost_virtqueue vqs[2];
     int backend;
+    const int *feature_bits;
     NetClientState *nc;
 };
 
diff --git a/include/net/vhost-vdpa.h b/include/net/vhost-vdpa.h
index 916ead3..f8d7d6c 100644
--- a/include/net/vhost-vdpa.h
+++ b/include/net/vhost-vdpa.h
@@ -14,6 +14,4 @@
 
 #define TYPE_VHOST_VDPA "vhost-vdpa"
 
-extern const int vdpa_feature_bits[];
-
 #endif /* VHOST_VDPA_H */
diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
index 0f40049..fbed373 100644
--- a/include/net/vhost_net.h
+++ b/include/net/vhost_net.h
@@ -12,6 +12,7 @@ typedef struct VhostNetOptions {
     NetClientState *net_backend;
     uint32_t busyloop_timeout;
     unsigned int nvqs;
+    const int *feature_bits;
     void *opaque;
 } VhostNetOptions;
 
diff --git a/net/tap.c b/net/tap.c
index 4beba6d..a33eb23 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -42,11 +42,29 @@
 #include "qemu/error-report.h"
 #include "qemu/main-loop.h"
 #include "qemu/sockets.h"
+#include "hw/virtio/vhost.h"
 
 #include "net/tap.h"
 
 #include "net/vhost_net.h"
 
+static const int kernel_feature_bits[] = {
+    VIRTIO_F_NOTIFY_ON_EMPTY,
+    VIRTIO_RING_F_INDIRECT_DESC,
+    VIRTIO_RING_F_EVENT_IDX,
+    VIRTIO_NET_F_MRG_RXBUF,
+    VIRTIO_F_VERSION_1,
+    VIRTIO_NET_F_MTU,
+    VIRTIO_F_IOMMU_PLATFORM,
+    VIRTIO_F_RING_PACKED,
+    VIRTIO_F_RING_RESET,
+    VIRTIO_F_IN_ORDER,
+    VIRTIO_F_NOTIFICATION_DATA,
+    VIRTIO_NET_F_RSC_EXT,
+    VIRTIO_NET_F_HASH_REPORT,
+    VHOST_INVALID_FEATURE_BIT
+};
+
 typedef struct TAPState {
     NetClientState nc;
     int fd;
@@ -725,6 +743,7 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
         }
         options.opaque = (void *)(uintptr_t)vhostfd;
         options.nvqs = 2;
+        options.feature_bits = kernel_feature_bits;
 
         s->vhost_net = vhost_net_init(&options);
         if (!s->vhost_net) {
diff --git a/net/vhost-user.c b/net/vhost-user.c
index b7bf0d2..bc8e82a 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -12,7 +12,9 @@
 #include "clients.h"
 #include "net/vhost_net.h"
 #include "net/vhost-user.h"
+#include "hw/virtio/vhost.h"
 #include "hw/virtio/vhost-user.h"
+#include "standard-headers/linux/virtio_net.h"
 #include "chardev/char-fe.h"
 #include "qapi/error.h"
 #include "qapi/qapi-commands-net.h"
@@ -22,6 +24,46 @@
 #include "qemu/option.h"
 #include "trace.h"
 
+static const int user_feature_bits[] = {
+    VIRTIO_F_NOTIFY_ON_EMPTY,
+    VIRTIO_F_NOTIFICATION_DATA,
+    VIRTIO_RING_F_INDIRECT_DESC,
+    VIRTIO_RING_F_EVENT_IDX,
+
+    VIRTIO_F_ANY_LAYOUT,
+    VIRTIO_F_VERSION_1,
+    VIRTIO_NET_F_CSUM,
+    VIRTIO_NET_F_GUEST_CSUM,
+    VIRTIO_NET_F_GSO,
+    VIRTIO_NET_F_GUEST_TSO4,
+    VIRTIO_NET_F_GUEST_TSO6,
+    VIRTIO_NET_F_GUEST_ECN,
+    VIRTIO_NET_F_GUEST_UFO,
+    VIRTIO_NET_F_HOST_TSO4,
+    VIRTIO_NET_F_HOST_TSO6,
+    VIRTIO_NET_F_HOST_ECN,
+    VIRTIO_NET_F_HOST_UFO,
+    VIRTIO_NET_F_MRG_RXBUF,
+    VIRTIO_NET_F_MTU,
+    VIRTIO_F_IOMMU_PLATFORM,
+    VIRTIO_F_RING_PACKED,
+    VIRTIO_F_RING_RESET,
+    VIRTIO_F_IN_ORDER,
+    VIRTIO_NET_F_RSS,
+    VIRTIO_NET_F_RSC_EXT,
+    VIRTIO_NET_F_HASH_REPORT,
+    VIRTIO_NET_F_GUEST_USO4,
+    VIRTIO_NET_F_GUEST_USO6,
+    VIRTIO_NET_F_HOST_USO,
+
+    /* This bit implies RARP isn't sent by QEMU out of band */
+    VIRTIO_NET_F_GUEST_ANNOUNCE,
+
+    VIRTIO_NET_F_MQ,
+
+    VHOST_INVALID_FEATURE_BIT
+};
+
 typedef struct NetVhostUserState {
     NetClientState nc;
     CharBackend chr; /* only queue index 0 */
@@ -96,6 +138,7 @@ static int vhost_user_start(int queues, NetClientState *ncs[],
         options.opaque      = be;
         options.busyloop_timeout = 0;
         options.nvqs = 2;
+        options.feature_bits = user_feature_bits;
         net = vhost_net_init(&options);
         if (!net) {
             error_report("failed to init vhost_net for queue %d", i);
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 0b86c91..cbbea0e 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -55,7 +55,7 @@ typedef struct VhostVDPAState {
  * with the exception of VHOST_INVALID_FEATURE_BIT,
  * which should always be the last entry.
  */
-const int vdpa_feature_bits[] = {
+static const int vdpa_feature_bits[] = {
     VIRTIO_F_ANY_LAYOUT,
     VIRTIO_F_IOMMU_PLATFORM,
     VIRTIO_F_NOTIFY_ON_EMPTY,
@@ -201,6 +201,7 @@ static int vhost_vdpa_add(NetClientState *ncs, void *be,
     options.opaque      = be;
     options.busyloop_timeout = 0;
     options.nvqs = nvqs;
+    options.feature_bits = vdpa_feature_bits;
 
     net = vhost_net_init(&options);
     if (!net) {