From 1c3e5a261709daee4a01f30b1534329b2eea386e Mon Sep 17 00:00:00 2001 From: Maxime Coquelin Date: Thu, 29 Mar 2018 09:52:33 +0200 Subject: vhost-user: back SET/GET_CONFIG requests with a protocol feature Without a dedicated protocol feature, QEMU cannot know whether the backend can handle VHOST_USER_SET_CONFIG and VHOST_USER_GET_CONFIG messages. This patch adds a protocol feature that is only advertised by QEMU if the device implements the config ops. Vhost user init fails if the device support the feature but the backend doesn't. The backend should only send VHOST_USER_SLAVE_CONFIG_CHANGE_MSG requests if the protocol feature has been negotiated. Signed-off-by: Maxime Coquelin Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Acked-by: Changpeng Liu --- hw/virtio/vhost-user.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'hw/virtio') diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index 44aea5c..38da869 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -46,6 +46,7 @@ enum VhostUserProtocolFeature { VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6, VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7, VHOST_USER_PROTOCOL_F_PAGEFAULT = 8, + VHOST_USER_PROTOCOL_F_CONFIG = 9, VHOST_USER_PROTOCOL_F_MAX }; @@ -1211,6 +1212,17 @@ static int vhost_user_init(struct vhost_dev *dev, void *opaque) dev->protocol_features = protocol_features & VHOST_USER_PROTOCOL_FEATURE_MASK; + + if (!dev->config_ops || !dev->config_ops->vhost_dev_config_notifier) { + /* Don't acknowledge CONFIG feature if device doesn't support it */ + dev->protocol_features &= ~(1ULL << VHOST_USER_PROTOCOL_F_CONFIG); + } else if (!(protocol_features & + (1ULL << VHOST_USER_PROTOCOL_F_CONFIG))) { + error_report("Device expects VHOST_USER_PROTOCOL_F_CONFIG " + "but backend does not support it."); + return -1; + } + err = vhost_user_set_protocol_features(dev, dev->protocol_features); if (err < 0) { return err; @@ -1405,6 +1417,11 @@ static int vhost_user_get_config(struct vhost_dev *dev, uint8_t *config, .hdr.size = VHOST_USER_CONFIG_HDR_SIZE + config_len, }; + if (!virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_CONFIG)) { + return -1; + } + if (config_len > VHOST_USER_MAX_CONFIG_SIZE) { return -1; } @@ -1448,6 +1465,11 @@ static int vhost_user_set_config(struct vhost_dev *dev, const uint8_t *data, .hdr.size = VHOST_USER_CONFIG_HDR_SIZE + size, }; + if (!virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_CONFIG)) { + return -1; + } + if (reply_supported) { msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK; } -- cgit v1.1