On 09/15/2015 03:10 PM, Yuanhan Liu wrote:
> From: "Michael S. Tsirkin" <m...@redhat.com>
>
> Support a separate bitmask for vhost-user protocol features,
> and messages to get/set protocol features.
>
> Invoke them at init.
>
> No features are defined yet.
>
> v2: leverage vhost_user_call for request handling -- Yuanhan Liu
>
> Signed-off-by: Michael S. Tsirkin <address@hidden>
> Signed-off-by: Yuanhan Liu <yuanhan....@linux.intel.com>
> ---
> docs/specs/vhost-user.txt | 37 +++++++++++++++++++++++++++++++++++++
> hw/net/vhost_net.c | 2 ++
> hw/virtio/vhost-user.c | 31 +++++++++++++++++++++++++++++++
> include/hw/virtio/vhost.h | 1 +
> 4 files changed, 71 insertions(+)
>
> diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> index 650bb18..70da3b1 100644
> --- a/docs/specs/vhost-user.txt
> +++ b/docs/specs/vhost-user.txt
> @@ -113,6 +113,7 @@ message replies. Most of the requests don't require
> replies. Here is a list of
> the ones that do:
>
> * VHOST_GET_FEATURES
> + * VHOST_GET_PROTOCOL_FEATURES
> * VHOST_GET_VRING_BASE
>
> There are several messages that the master sends with file descriptors passed
> @@ -127,6 +128,13 @@ in the ancillary data:
> If Master is unable to send the full message or receives a wrong reply it
> will
> close the connection. An optional reconnection mechanism can be implemented.
>
> +Any protocol extensions are gated by protocol feature bits,
> +which allows full backwards compatibility on both master
> +and slave.
> +As older slaves don't support negotiating protocol features,
> +a feature bit was dedicated for this purpose:
> +#define VHOST_USER_F_PROTOCOL_FEATURES 30
> +
> Message types
> -------------
>
> @@ -138,6 +146,8 @@ Message types
> Slave payload: u64
>
> Get from the underlying vhost implementation the features bitmask.
> + Feature bit VHOST_USER_F_PROTOCOL_FEATURES signals slave support for
> + VHOST_USER_GET_PROTOCOL_FEATURES and VHOST_USER_SET_PROTOCOL_FEATURES.
>
> * VHOST_USER_SET_FEATURES
>
> @@ -146,6 +156,33 @@ Message types
> Master payload: u64
>
> Enable features in the underlying vhost implementation using a bitmask.
> + Feature bit VHOST_USER_F_PROTOCOL_FEATURES signals slave support for
> + VHOST_USER_GET_PROTOCOL_FEATURES and VHOST_USER_SET_PROTOCOL_FEATURES.
> +
> + * VHOST_USER_GET_PROTOCOL_FEATURES
> +
> + Id: 15
> + Equivalent ioctl: VHOST_GET_FEATURES
> + Master payload: N/A
> + Slave payload: u64
> +
> + Get the protocol feature bitmask from the underlying vhost
> implementation.
> + Only legal if feature bit VHOST_USER_F_PROTOCOL_FEATURES is present in
> + VHOST_USER_GET_FEATURES.
> + Note: slave that reported VHOST_USER_F_PROTOCOL_FEATURES must support
> + this message even before VHOST_USER_SET_FEATURES was called.
> +
> + * VHOST_USER_SET_PROTOCOL_FEATURES
> +
> + Id: 16
> + Ioctl: VHOST_SET_FEATURES
> + Master payload: u64
> +
> + Enable protocol features in the underlying vhost implementation.
> + Only legal if feature bit VHOST_USER_F_PROTOCOL_FEATURES is present in
> + VHOST_USER_GET_FEATURES.
> + Note: slave that reported VHOST_USER_F_PROTOCOL_FEATURES must support
> + this message even before VHOST_USER_SET_FEATURES was called.
>
> * VHOST_USER_SET_OWNER
>
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index 5c1d11f..c864237 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -152,8 +152,10 @@ struct vhost_net *vhost_net_init(VhostNetOptions
> *options)
> net->dev.backend_features = qemu_has_vnet_hdr(options->net_backend)
> ? 0 : (1ULL << VHOST_NET_F_VIRTIO_NET_HDR);
> net->backend = r;
> + net->dev.protocol_features = 0;
> } else {
> net->dev.backend_features = 0;
> + net->dev.protocol_features = 0;
> net->backend = -1;
> }
> net->nc = options->net_backend;
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 13677ac..43169a1 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -24,6 +24,8 @@
> #include <linux/vhost.h>
>
> #define VHOST_MEMORY_MAX_NREGIONS 8
> +#define VHOST_USER_F_PROTOCOL_FEATURES 30
> +#define VHOST_USER_PROTOCOL_FEATURE_MASK 0x0ULL
>
> typedef enum VhostUserRequest {
> VHOST_USER_NONE = 0,
> @@ -41,6 +43,8 @@ typedef enum VhostUserRequest {
> VHOST_USER_SET_VRING_KICK = 12,
> VHOST_USER_SET_VRING_CALL = 13,
> VHOST_USER_SET_VRING_ERR = 14,
> + VHOST_USER_GET_PROTOCOL_FEATURES = 15,
> + VHOST_USER_SET_PROTOCOL_FEATURES = 16,
> VHOST_USER_MAX
> } VhostUserRequest;
>
> @@ -206,11 +210,13 @@ static int vhost_user_call(struct vhost_dev *dev,
> unsigned long int request,
>
> switch (msg_request) {
> case VHOST_USER_GET_FEATURES:
> + case VHOST_USER_GET_PROTOCOL_FEATURES:
> need_reply = 1;
> break;
>
> case VHOST_USER_SET_FEATURES:
> case VHOST_USER_SET_LOG_BASE:
> + case VHOST_USER_SET_PROTOCOL_FEATURES:
> msg.u64 = *((__u64 *) arg);
> msg.size = sizeof(m.u64);
> break;
> @@ -308,6 +314,7 @@ static int vhost_user_call(struct vhost_dev *dev,
> unsigned long int request,
>
> switch (msg_request) {
> case VHOST_USER_GET_FEATURES:
> + case VHOST_USER_GET_PROTOCOL_FEATURES:
> if (msg.size != sizeof(m.u64)) {
> error_report("Received bad msg size.");
> return -1;
> @@ -333,10 +340,34 @@ static int vhost_user_call(struct vhost_dev *dev,
> unsigned long int request,
>
> static int vhost_user_init(struct vhost_dev *dev, void *opaque)
> {
> + unsigned long long features;
> + int err;
> +
> assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
>
> dev->opaque = opaque;
>
> + err = vhost_user_call(dev, VHOST_USER_GET_FEATURES, &features);
> + if (err < 0) {
> + return err;
> + }
> +
> + if (__virtio_has_feature(features, VHOST_USER_F_PROTOCOL_FEATURES)) {
Need rebase to master. (And use virtio_has_feature() here).
> + dev->backend_features |= 1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
> +
> + err = vhost_user_call(dev, VHOST_USER_GET_PROTOCOL_FEATURES,
> &features);
> + if (err < 0) {
> + return err;
> + }
> +
> + dev->protocol_features = features & VHOST_USER_PROTOCOL_FEATURE_MASK;
> + err = vhost_user_call(dev, VHOST_USER_SET_PROTOCOL_FEATURES,
> + &dev->protocol_features);
> + if (err < 0) {
> + return err;
> + }
> + }
> +
> return 0;
> }
>
> diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> index dd51050..6467c73 100644
> --- a/include/hw/virtio/vhost.h
> +++ b/include/hw/virtio/vhost.h
> @@ -47,6 +47,7 @@ struct vhost_dev {
> unsigned long long features;
> unsigned long long acked_features;
> unsigned long long backend_features;
> + unsigned long long protocol_features;
> bool started;
> bool log_enabled;
> unsigned long long log_size;
