It's hard to control where and how do we use this field. Let's
cover all usages by getters/setters, and keep direct access to the
field only in vhost.c. It will help to control migration of this
field in further commits.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
hw/display/vhost-user-gpu.c | 7 +++----
hw/net/vhost_net.c | 17 +++++++++--------
hw/virtio/vdpa-dev.c | 2 +-
hw/virtio/vhost-user-base.c | 8 ++++++--
hw/virtio/vhost-user.c | 7 +++----
hw/virtio/vhost.c | 21 ++++++++++++++++++---
hw/virtio/virtio-qmp.c | 2 +-
include/hw/virtio/vhost.h | 21 +++++++++++++++++++--
net/vhost-vdpa.c | 7 +++----
9 files changed, 63 insertions(+), 29 deletions(-)
diff --git a/hw/display/vhost-user-gpu.c b/hw/display/vhost-user-gpu.c
index 79ea64b12c..146620e0a3 100644
--- a/hw/display/vhost-user-gpu.c
+++ b/hw/display/vhost-user-gpu.c
@@ -631,17 +631,16 @@ vhost_user_gpu_device_realize(DeviceState *qdev, Error **errp)
/* existing backend may send DMABUF, so let's add that requirement */
g->parent_obj.conf.flags |= 1 << VIRTIO_GPU_FLAG_DMABUF_ENABLED;
- if (virtio_has_feature(g->vhost->dev.features, VIRTIO_GPU_F_VIRGL)) {
+ if (vhost_dev_has_feature(&g->vhost->dev, VIRTIO_GPU_F_VIRGL)) {
g->parent_obj.conf.flags |= 1 << VIRTIO_GPU_FLAG_VIRGL_ENABLED;
}
- if (virtio_has_feature(g->vhost->dev.features, VIRTIO_GPU_F_EDID)) {
+ if (vhost_dev_has_feature(&g->vhost->dev, VIRTIO_GPU_F_EDID)) {
g->parent_obj.conf.flags |= 1 << VIRTIO_GPU_FLAG_EDID_ENABLED;
} else {
error_report("EDID requested but the backend doesn't support it.");
g->parent_obj.conf.flags &= ~(1 << VIRTIO_GPU_FLAG_EDID_ENABLED);
}
- if (virtio_has_feature(g->vhost->dev.features,
- VIRTIO_GPU_F_RESOURCE_UUID)) {
+ if (vhost_dev_has_feature(&g->vhost->dev, VIRTIO_GPU_F_RESOURCE_UUID)) {
g->parent_obj.conf.flags |= 1 << VIRTIO_GPU_FLAG_RESOURCE_UUID_ENABLED;
}
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index ce30b6e197..5269533864 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -55,7 +55,8 @@ void vhost_net_ack_features(struct vhost_net *net, uint64_t features)
{
net->dev.acked_features =
(qemu_has_vnet_hdr(net->nc) ? 0 : (1ULL << VHOST_NET_F_VIRTIO_NET_HDR))
- | (net->dev.features & (1ULL << VHOST_USER_F_PROTOCOL_FEATURES));
+ | (vhost_dev_features(&net->dev) &
+ (1ULL << VHOST_USER_F_PROTOCOL_FEATURES));
vhost_ack_features(&net->dev, net->feature_bits, features);
}
@@ -277,23 +278,23 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
if (backend_kernel) {
if (!qemu_has_vnet_hdr_len(options->net_backend,
sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
- net->dev.features &= ~(1ULL << VIRTIO_NET_F_MRG_RXBUF);
+ vhost_dev_clear_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF);
}
if (!qemu_has_vnet_hdr(options->net_backend) &&
- (~net->dev.features & (1ULL << VHOST_NET_F_VIRTIO_NET_HDR))) {
- fprintf(stderr, "vhost lacks feature mask 0x%llx for backend\n",
- ~net->dev.features & (1ULL << VHOST_NET_F_VIRTIO_NET_HDR));
+ !vhost_dev_has_feature(&net->dev, VHOST_NET_F_VIRTIO_NET_HDR)) {
+ fprintf(stderr, "vhost lacks VHOST_NET_F_VIRTIO_NET_HDR "
+ "feature for backend\n");
goto fail;
}
}
/* Set sane init value. Override when guest acks. */
if (options->get_acked_features) {
+ uint64_t backend_features = vhost_dev_features(&net->dev);
features = options->get_acked_features(net->nc);
- if (~net->dev.features & features) {
+ if (~backend_features & features) {
fprintf(stderr, "vhost lacks feature mask 0x%" PRIx64
- " for backend\n",
- (uint64_t)(~net->dev.features & features));
+ " for backend\n", ~backend_features & features);
goto fail;
}
}
diff --git a/hw/virtio/vdpa-dev.c b/hw/virtio/vdpa-dev.c
index 3c0eed3e8e..4dfb03aaa7 100644
--- a/hw/virtio/vdpa-dev.c
+++ b/hw/virtio/vdpa-dev.c
@@ -224,7 +224,7 @@ static uint64_t vhost_vdpa_device_get_features(VirtIODevice *vdev,
Error **errp)
{
VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
- uint64_t backend_features = s->dev.features;
+ uint64_t backend_features = vhost_dev_features(&s->dev);
if (!virtio_has_feature(features, VIRTIO_F_IOMMU_PLATFORM)) {
virtio_clear_feature(&backend_features, VIRTIO_F_IOMMU_PLATFORM);
diff --git a/hw/virtio/vhost-user-base.c b/hw/virtio/vhost-user-base.c
index ff67a020b4..cf311c3bfc 100644
--- a/hw/virtio/vhost-user-base.c
+++ b/hw/virtio/vhost-user-base.c
@@ -118,9 +118,13 @@ static uint64_t vub_get_features(VirtIODevice *vdev,
uint64_t requested_features, Error **errp)
{
VHostUserBase *vub = VHOST_USER_BASE(vdev);
+ uint64_t backend_features = vhost_dev_features(&vub->vhost_dev);
+
/* This should be set when the vhost connection initialises */
- g_assert(vub->vhost_dev.features);
- return vub->vhost_dev.features & ~(1ULL << VHOST_USER_F_PROTOCOL_FEATURES);
+ g_assert(backend_features);
+ virtio_clear_feature(&backend_features, VHOST_USER_F_PROTOCOL_FEATURES);
+
+ return backend_features;
}
/*
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index abdf47ee7b..46f09f5988 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -1245,15 +1245,14 @@ static int vhost_user_set_vring_base(struct vhost_dev *dev,
static bool vhost_user_set_vring_enable_supported(struct vhost_dev *dev)
{
- return virtio_has_feature(dev->features,
- VHOST_USER_F_PROTOCOL_FEATURES);
+ return vhost_dev_has_feature(dev, VHOST_USER_F_PROTOCOL_FEATURES);
}
static int vhost_user_set_vring_enable(struct vhost_dev *dev, int enable)
{
int i;
- if (!virtio_has_feature(dev->features, VHOST_USER_F_PROTOCOL_FEATURES)) {
+ if (!vhost_dev_has_feature(dev, VHOST_USER_F_PROTOCOL_FEATURES)) {
return -EINVAL;
}
@@ -1465,7 +1464,7 @@ static int vhost_user_set_features(struct vhost_dev *dev,
* Don't lose VHOST_USER_F_PROTOCOL_FEATURES, which is vhost-user
* specific.
*/
- if (virtio_has_feature(dev->features, VHOST_USER_F_PROTOCOL_FEATURES)) {
+ if (vhost_dev_has_feature(dev, VHOST_USER_F_PROTOCOL_FEATURES)) {
features |= 1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
}
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index c33dad4acd..2631bbabcf 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -50,6 +50,21 @@ static QLIST_HEAD(, vhost_dev) vhost_log_devs[VHOST_BACKEND_TYPE_MAX];
static QLIST_HEAD(, vhost_dev) vhost_devices =
QLIST_HEAD_INITIALIZER(vhost_devices);
+bool vhost_dev_has_feature(struct vhost_dev *dev, uint64_t feature)
+{
+ return virtio_has_feature(dev->_features, feature);
+}
+
+uint64_t vhost_dev_features(struct vhost_dev *dev)
+{
+ return dev->_features;
+}
+
+void vhost_dev_clear_feature(struct vhost_dev *dev, uint64_t feature)
+{
+ virtio_clear_feature(&dev->_features, feature);
+}
+
unsigned int vhost_get_max_memslots(void)
{
unsigned int max = UINT_MAX;
@@ -1571,7 +1586,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
}
}
- hdev->features = features;
+ hdev->_features = features;
hdev->memory_listener = (MemoryListener) {
.name = "vhost",
@@ -1594,7 +1609,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
};
if (hdev->migration_blocker == NULL) {
- if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) {
+ if (!vhost_dev_has_feature(hdev, VHOST_F_LOG_ALL)) {
error_setg(&hdev->migration_blocker,
"Migration disabled: vhost lacks VHOST_F_LOG_ALL feature.");
} else if (vhost_dev_log_is_shared(hdev) && !qemu_memfd_alloc_check()) {
@@ -1865,7 +1880,7 @@ uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits,
const int *bit = feature_bits;
while (*bit != VHOST_INVALID_FEATURE_BIT) {
uint64_t bit_mask = (1ULL << *bit);
- if (!(hdev->features & bit_mask)) {
+ if (!vhost_dev_has_feature(hdev, *bit)) {
features &= ~bit_mask;
}
bit++;
diff --git a/hw/virtio/virtio-qmp.c b/hw/virtio/virtio-qmp.c
index d55b12f9f3..4bd23c015e 100644
--- a/hw/virtio/virtio-qmp.c
+++ b/hw/virtio/virtio-qmp.c
@@ -785,7 +785,7 @@ VirtioStatus *qmp_x_query_virtio_status(const char *path, Error **errp)
status->vhost_dev->nvqs = hdev->nvqs;
status->vhost_dev->vq_index = hdev->vq_index;
status->vhost_dev->features =
- qmp_decode_features(vdev->device_id, hdev->features);
+ qmp_decode_features(vdev->device_id, vhost_dev_features(hdev));
status->vhost_dev->acked_features =
qmp_decode_features(vdev->device_id, hdev->acked_features);
status->vhost_dev->max_queues = hdev->max_queues;
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index 15bc287a9d..8a4c8c3502 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -98,10 +98,11 @@ struct vhost_dev {
* offered by a backend which may be a subset of the total
* features eventually offered to the guest.
*
- * @features: available features provided by the backend
+ * @_features: available features provided by the backend, private,
+ * direct access only in vhost.c
* @acked_features: final negotiated features with front-end driver
*/
- uint64_t features;
+ uint64_t _features;
uint64_t acked_features;
uint64_t max_queues;
@@ -352,6 +353,22 @@ int vhost_dev_get_inflight(struct vhost_dev *dev, uint16_t queue_size,
struct vhost_inflight *inflight);
bool vhost_dev_has_iommu(struct vhost_dev *dev);
+/**
+ * vhost_dev_has_feature() - check if vhost device has a specific feature
+ * @dev: common vhost_dev structure
+ * @feature: feature bit to check
+ *
+ * Return: true if the feature is supported, false otherwise
+ */
+bool vhost_dev_has_feature(struct vhost_dev *dev, uint64_t feature);
+
+/**
+ * vhost_dev_features() - simple getter for dev->features
+ */
+uint64_t vhost_dev_features(struct vhost_dev *dev);
+
+void vhost_dev_clear_feature(struct vhost_dev *dev, uint64_t feature);
+
#ifdef CONFIG_VHOST
int vhost_reset_device(struct vhost_dev *hdev);
#else
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 74d26a9497..0af0d3bdd3 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -256,15 +256,14 @@ static bool vhost_vdpa_get_vnet_hash_supported_types(NetClientState *nc,
{
assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);
VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
- uint64_t features = s->vhost_vdpa.dev->features;
int fd = s->vhost_vdpa.shared->device_fd;
struct {
struct vhost_vdpa_config hdr;
uint32_t supported_hash_types;
} config;
- if (!virtio_has_feature(features, VIRTIO_NET_F_HASH_REPORT) &&
- !virtio_has_feature(features, VIRTIO_NET_F_RSS)) {
+ if (!vhost_dev_has_feature(s->vhost_vdpa.dev, VIRTIO_NET_F_HASH_REPORT) &&
+ !vhost_dev_has_feature(s->vhost_vdpa.dev, VIRTIO_NET_F_RSS)) {
return false;
}
@@ -585,7 +584,7 @@ static int vhost_vdpa_net_cvq_start(NetClientState *nc)
* If we early return in these cases SVQ will not be enabled. The migration
* will be blocked as long as vhost-vdpa backends will not offer _F_LOG.
*/
- if (!vhost_vdpa_net_valid_svq_features(v->dev->features, NULL)) {
+ if (!vhost_vdpa_net_valid_svq_features(vhost_dev_features(v->dev), NULL)) {
return 0;
}
--
2.48.1On Wed, Aug 13, 2025 at 12:58 PM Vladimir Sementsov-Ogievskiy
<vsementsov@yandex-team.ru> wrote:
>
> It's hard to control where and how do we use this field. Let's
> cover all usages by getters/setters, and keep direct access to the
> field only in vhost.c. It will help to control migration of this
> field in further commits.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> ---
> hw/display/vhost-user-gpu.c | 7 +++----
> hw/net/vhost_net.c | 17 +++++++++--------
> hw/virtio/vdpa-dev.c | 2 +-
> hw/virtio/vhost-user-base.c | 8 ++++++--
> hw/virtio/vhost-user.c | 7 +++----
> hw/virtio/vhost.c | 21 ++++++++++++++++++---
> hw/virtio/virtio-qmp.c | 2 +-
> include/hw/virtio/vhost.h | 21 +++++++++++++++++++--
> net/vhost-vdpa.c | 7 +++----
> 9 files changed, 63 insertions(+), 29 deletions(-)
>
> diff --git a/hw/display/vhost-user-gpu.c b/hw/display/vhost-user-gpu.c
> index 79ea64b12c..146620e0a3 100644
> --- a/hw/display/vhost-user-gpu.c
> +++ b/hw/display/vhost-user-gpu.c
> @@ -631,17 +631,16 @@ vhost_user_gpu_device_realize(DeviceState *qdev, Error **errp)
>
> /* existing backend may send DMABUF, so let's add that requirement */
> g->parent_obj.conf.flags |= 1 << VIRTIO_GPU_FLAG_DMABUF_ENABLED;
> - if (virtio_has_feature(g->vhost->dev.features, VIRTIO_GPU_F_VIRGL)) {
> + if (vhost_dev_has_feature(&g->vhost->dev, VIRTIO_GPU_F_VIRGL)) {
> g->parent_obj.conf.flags |= 1 << VIRTIO_GPU_FLAG_VIRGL_ENABLED;
> }
> - if (virtio_has_feature(g->vhost->dev.features, VIRTIO_GPU_F_EDID)) {
> + if (vhost_dev_has_feature(&g->vhost->dev, VIRTIO_GPU_F_EDID)) {
> g->parent_obj.conf.flags |= 1 << VIRTIO_GPU_FLAG_EDID_ENABLED;
> } else {
> error_report("EDID requested but the backend doesn't support it.");
> g->parent_obj.conf.flags &= ~(1 << VIRTIO_GPU_FLAG_EDID_ENABLED);
> }
> - if (virtio_has_feature(g->vhost->dev.features,
> - VIRTIO_GPU_F_RESOURCE_UUID)) {
> + if (vhost_dev_has_feature(&g->vhost->dev, VIRTIO_GPU_F_RESOURCE_UUID)) {
> g->parent_obj.conf.flags |= 1 << VIRTIO_GPU_FLAG_RESOURCE_UUID_ENABLED;
> }
>
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index ce30b6e197..5269533864 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -55,7 +55,8 @@ void vhost_net_ack_features(struct vhost_net *net, uint64_t features)
> {
> net->dev.acked_features =
> (qemu_has_vnet_hdr(net->nc) ? 0 : (1ULL << VHOST_NET_F_VIRTIO_NET_HDR))
> - | (net->dev.features & (1ULL << VHOST_USER_F_PROTOCOL_FEATURES));
> + | (vhost_dev_features(&net->dev) &
> + (1ULL << VHOST_USER_F_PROTOCOL_FEATURES));
>
> vhost_ack_features(&net->dev, net->feature_bits, features);
> }
> @@ -277,23 +278,23 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
> if (backend_kernel) {
> if (!qemu_has_vnet_hdr_len(options->net_backend,
> sizeof(struct virtio_net_hdr_mrg_rxbuf))) {
> - net->dev.features &= ~(1ULL << VIRTIO_NET_F_MRG_RXBUF);
> + vhost_dev_clear_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF);
> }
> if (!qemu_has_vnet_hdr(options->net_backend) &&
> - (~net->dev.features & (1ULL << VHOST_NET_F_VIRTIO_NET_HDR))) {
> - fprintf(stderr, "vhost lacks feature mask 0x%llx for backend\n",
> - ~net->dev.features & (1ULL << VHOST_NET_F_VIRTIO_NET_HDR));
> + !vhost_dev_has_feature(&net->dev, VHOST_NET_F_VIRTIO_NET_HDR)) {
> + fprintf(stderr, "vhost lacks VHOST_NET_F_VIRTIO_NET_HDR "
> + "feature for backend\n");
> goto fail;
> }
> }
>
> /* Set sane init value. Override when guest acks. */
> if (options->get_acked_features) {
> + uint64_t backend_features = vhost_dev_features(&net->dev);
> features = options->get_acked_features(net->nc);
> - if (~net->dev.features & features) {
> + if (~backend_features & features) {
> fprintf(stderr, "vhost lacks feature mask 0x%" PRIx64
> - " for backend\n",
> - (uint64_t)(~net->dev.features & features));
> + " for backend\n", ~backend_features & features);
> goto fail;
> }
> }
> diff --git a/hw/virtio/vdpa-dev.c b/hw/virtio/vdpa-dev.c
> index 3c0eed3e8e..4dfb03aaa7 100644
> --- a/hw/virtio/vdpa-dev.c
> +++ b/hw/virtio/vdpa-dev.c
> @@ -224,7 +224,7 @@ static uint64_t vhost_vdpa_device_get_features(VirtIODevice *vdev,
> Error **errp)
> {
> VhostVdpaDevice *s = VHOST_VDPA_DEVICE(vdev);
> - uint64_t backend_features = s->dev.features;
> + uint64_t backend_features = vhost_dev_features(&s->dev);
>
> if (!virtio_has_feature(features, VIRTIO_F_IOMMU_PLATFORM)) {
> virtio_clear_feature(&backend_features, VIRTIO_F_IOMMU_PLATFORM);
> diff --git a/hw/virtio/vhost-user-base.c b/hw/virtio/vhost-user-base.c
> index ff67a020b4..cf311c3bfc 100644
> --- a/hw/virtio/vhost-user-base.c
> +++ b/hw/virtio/vhost-user-base.c
> @@ -118,9 +118,13 @@ static uint64_t vub_get_features(VirtIODevice *vdev,
> uint64_t requested_features, Error **errp)
> {
> VHostUserBase *vub = VHOST_USER_BASE(vdev);
> + uint64_t backend_features = vhost_dev_features(&vub->vhost_dev);
> +
> /* This should be set when the vhost connection initialises */
> - g_assert(vub->vhost_dev.features);
> - return vub->vhost_dev.features & ~(1ULL << VHOST_USER_F_PROTOCOL_FEATURES);
> + g_assert(backend_features);
> + virtio_clear_feature(&backend_features, VHOST_USER_F_PROTOCOL_FEATURES);
> +
> + return backend_features;
> }
>
> /*
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index abdf47ee7b..46f09f5988 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -1245,15 +1245,14 @@ static int vhost_user_set_vring_base(struct vhost_dev *dev,
>
> static bool vhost_user_set_vring_enable_supported(struct vhost_dev *dev)
> {
> - return virtio_has_feature(dev->features,
> - VHOST_USER_F_PROTOCOL_FEATURES);
> + return vhost_dev_has_feature(dev, VHOST_USER_F_PROTOCOL_FEATURES);
> }
>
> static int vhost_user_set_vring_enable(struct vhost_dev *dev, int enable)
> {
> int i;
>
> - if (!virtio_has_feature(dev->features, VHOST_USER_F_PROTOCOL_FEATURES)) {
> + if (!vhost_dev_has_feature(dev, VHOST_USER_F_PROTOCOL_FEATURES)) {
> return -EINVAL;
> }
>
> @@ -1465,7 +1464,7 @@ static int vhost_user_set_features(struct vhost_dev *dev,
> * Don't lose VHOST_USER_F_PROTOCOL_FEATURES, which is vhost-user
> * specific.
> */
> - if (virtio_has_feature(dev->features, VHOST_USER_F_PROTOCOL_FEATURES)) {
> + if (vhost_dev_has_feature(dev, VHOST_USER_F_PROTOCOL_FEATURES)) {
> features |= 1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
> }
>
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index c33dad4acd..2631bbabcf 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -50,6 +50,21 @@ static QLIST_HEAD(, vhost_dev) vhost_log_devs[VHOST_BACKEND_TYPE_MAX];
> static QLIST_HEAD(, vhost_dev) vhost_devices =
> QLIST_HEAD_INITIALIZER(vhost_devices);
>
> +bool vhost_dev_has_feature(struct vhost_dev *dev, uint64_t feature)
> +{
> + return virtio_has_feature(dev->_features, feature);
> +}
> +
> +uint64_t vhost_dev_features(struct vhost_dev *dev)
> +{
> + return dev->_features;
> +}
> +
> +void vhost_dev_clear_feature(struct vhost_dev *dev, uint64_t feature)
> +{
> + virtio_clear_feature(&dev->_features, feature);
> +}
> +
> unsigned int vhost_get_max_memslots(void)
> {
> unsigned int max = UINT_MAX;
> @@ -1571,7 +1586,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
> }
> }
>
> - hdev->features = features;
> + hdev->_features = features;
>
> hdev->memory_listener = (MemoryListener) {
> .name = "vhost",
> @@ -1594,7 +1609,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
> };
>
> if (hdev->migration_blocker == NULL) {
> - if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) {
> + if (!vhost_dev_has_feature(hdev, VHOST_F_LOG_ALL)) {
> error_setg(&hdev->migration_blocker,
> "Migration disabled: vhost lacks VHOST_F_LOG_ALL feature.");
> } else if (vhost_dev_log_is_shared(hdev) && !qemu_memfd_alloc_check()) {
> @@ -1865,7 +1880,7 @@ uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits,
> const int *bit = feature_bits;
> while (*bit != VHOST_INVALID_FEATURE_BIT) {
> uint64_t bit_mask = (1ULL << *bit);
> - if (!(hdev->features & bit_mask)) {
> + if (!vhost_dev_has_feature(hdev, *bit)) {
> features &= ~bit_mask;
> }
> bit++;
> diff --git a/hw/virtio/virtio-qmp.c b/hw/virtio/virtio-qmp.c
> index d55b12f9f3..4bd23c015e 100644
> --- a/hw/virtio/virtio-qmp.c
> +++ b/hw/virtio/virtio-qmp.c
> @@ -785,7 +785,7 @@ VirtioStatus *qmp_x_query_virtio_status(const char *path, Error **errp)
> status->vhost_dev->nvqs = hdev->nvqs;
> status->vhost_dev->vq_index = hdev->vq_index;
> status->vhost_dev->features =
> - qmp_decode_features(vdev->device_id, hdev->features);
> + qmp_decode_features(vdev->device_id, vhost_dev_features(hdev));
> status->vhost_dev->acked_features =
> qmp_decode_features(vdev->device_id, hdev->acked_features);
> status->vhost_dev->max_queues = hdev->max_queues;
> diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> index 15bc287a9d..8a4c8c3502 100644
> --- a/include/hw/virtio/vhost.h
> +++ b/include/hw/virtio/vhost.h
> @@ -98,10 +98,11 @@ struct vhost_dev {
> * offered by a backend which may be a subset of the total
> * features eventually offered to the guest.
> *
> - * @features: available features provided by the backend
> + * @_features: available features provided by the backend, private,
> + * direct access only in vhost.c
> * @acked_features: final negotiated features with front-end driver
> */
> - uint64_t features;
> + uint64_t _features;
> uint64_t acked_features;
>
> uint64_t max_queues;
> @@ -352,6 +353,22 @@ int vhost_dev_get_inflight(struct vhost_dev *dev, uint16_t queue_size,
> struct vhost_inflight *inflight);
> bool vhost_dev_has_iommu(struct vhost_dev *dev);
>
> +/**
> + * vhost_dev_has_feature() - check if vhost device has a specific feature
> + * @dev: common vhost_dev structure
> + * @feature: feature bit to check
> + *
> + * Return: true if the feature is supported, false otherwise
> + */
> +bool vhost_dev_has_feature(struct vhost_dev *dev, uint64_t feature);
> +
> +/**
> + * vhost_dev_features() - simple getter for dev->features
> + */
> +uint64_t vhost_dev_features(struct vhost_dev *dev);
> +
> +void vhost_dev_clear_feature(struct vhost_dev *dev, uint64_t feature);
Why not define these as static inline helpers in the header file?
> +
> #ifdef CONFIG_VHOST
> int vhost_reset_device(struct vhost_dev *hdev);
> #else
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 74d26a9497..0af0d3bdd3 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -256,15 +256,14 @@ static bool vhost_vdpa_get_vnet_hash_supported_types(NetClientState *nc,
> {
> assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);
> VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
> - uint64_t features = s->vhost_vdpa.dev->features;
> int fd = s->vhost_vdpa.shared->device_fd;
> struct {
> struct vhost_vdpa_config hdr;
> uint32_t supported_hash_types;
> } config;
>
> - if (!virtio_has_feature(features, VIRTIO_NET_F_HASH_REPORT) &&
> - !virtio_has_feature(features, VIRTIO_NET_F_RSS)) {
> + if (!vhost_dev_has_feature(s->vhost_vdpa.dev, VIRTIO_NET_F_HASH_REPORT) &&
> + !vhost_dev_has_feature(s->vhost_vdpa.dev, VIRTIO_NET_F_RSS)) {
> return false;
> }
>
> @@ -585,7 +584,7 @@ static int vhost_vdpa_net_cvq_start(NetClientState *nc)
> * If we early return in these cases SVQ will not be enabled. The migration
> * will be blocked as long as vhost-vdpa backends will not offer _F_LOG.
> */
> - if (!vhost_vdpa_net_valid_svq_features(v->dev->features, NULL)) {
> + if (!vhost_vdpa_net_valid_svq_features(vhost_dev_features(v->dev), NULL)) {
> return 0;
> }
>
> --
> 2.48.1
>
>
On 09.10.25 21:58, Raphael Norwitz wrote: > On Wed, Aug 13, 2025 at 12:58 PM Vladimir Sementsov-Ogievskiy > <vsementsov@yandex-team.ru> wrote: >> >> It's hard to control where and how do we use this field. Let's >> cover all usages by getters/setters, and keep direct access to the >> field only in vhost.c. It will help to control migration of this >> field in further commits. >> >> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> >> --- [..] >> +/** >> + * vhost_dev_has_feature() - check if vhost device has a specific feature >> + * @dev: common vhost_dev structure >> + * @feature: feature bit to check >> + * >> + * Return: true if the feature is supported, false otherwise >> + */ >> +bool vhost_dev_has_feature(struct vhost_dev *dev, uint64_t feature); >> + >> +/** >> + * vhost_dev_features() - simple getter for dev->features >> + */ >> +uint64_t vhost_dev_features(struct vhost_dev *dev); >> + >> +void vhost_dev_clear_feature(struct vhost_dev *dev, uint64_t feature); > > Why not define these as static inline helpers in the header file? > Agree, will do. > >> + >> #ifdef CONFIG_VHOST >> int vhost_reset_device(struct vhost_dev *hdev); >> #else -- Best regards, Vladimir
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