From: Stefano Garzarella <sgarzare@xxxxxxxxxx> commit 65b709586e222fa6ffd4166ac7fdb5d5dad113ee upstream. The get_config callback can be used by the device to fill the config structure. The callback will be invoked in vdpasim_get_config() before copying bytes into caller buffer. Move vDPA-net config updates from vdpasim_set_features() in the new vdpasim_net_get_config() callback. This is safe since in vdpa_get_config() we already check that .set_features() callback is called before .get_config(). Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> Link: https://lore.kernel.org/r/20201215144256.155342-13-sgarzare@xxxxxxxxxx Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/vdpa/vdpa_sim/vdpa_sim.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c @@ -69,9 +69,12 @@ static u64 vdpasim_features = (1ULL << V (1ULL << VIRTIO_F_ACCESS_PLATFORM) | (1ULL << VIRTIO_NET_F_MAC); +struct vdpasim; + struct vdpasim_dev_attr { size_t config_size; int nvqs; + void (*get_config)(struct vdpasim *vdpasim, void *config); }; /* State of each vdpasim device */ @@ -524,8 +527,6 @@ static u64 vdpasim_get_features(struct v static int vdpasim_set_features(struct vdpa_device *vdpa, u64 features) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); - struct virtio_net_config *config = - (struct virtio_net_config *)vdpasim->config; /* DMA mapping must be done by driver */ if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) @@ -533,16 +534,6 @@ static int vdpasim_set_features(struct v vdpasim->features = features & vdpasim_features; - /* We generally only know whether guest is using the legacy interface - * here, so generally that's the earliest we can set config fields. - * Note: We actually require VIRTIO_F_ACCESS_PLATFORM above which - * implies VIRTIO_F_VERSION_1, but let's not try to be clever here. - */ - - config->mtu = cpu_to_vdpasim16(vdpasim, 1500); - config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP); - memcpy(config->mac, macaddr_buf, ETH_ALEN); - return 0; } @@ -595,8 +586,13 @@ static void vdpasim_get_config(struct vd { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); - if (offset + len < vdpasim->dev_attr.config_size) - memcpy(buf, vdpasim->config + offset, len); + if (offset + len > vdpasim->dev_attr.config_size) + return; + + if (vdpasim->dev_attr.get_config) + vdpasim->dev_attr.get_config(vdpasim, vdpasim->config); + + memcpy(buf, vdpasim->config + offset, len); } static void vdpasim_set_config(struct vdpa_device *vdpa, unsigned int offset, @@ -739,12 +735,23 @@ static const struct vdpa_config_ops vdpa .free = vdpasim_free, }; +static void vdpasim_net_get_config(struct vdpasim *vdpasim, void *config) +{ + struct virtio_net_config *net_config = + (struct virtio_net_config *)config; + + net_config->mtu = cpu_to_vdpasim16(vdpasim, 1500); + net_config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP); + memcpy(net_config->mac, macaddr_buf, ETH_ALEN); +} + static int __init vdpasim_dev_init(void) { struct vdpasim_dev_attr dev_attr = {}; dev_attr.nvqs = VDPASIM_VQ_NUM; dev_attr.config_size = sizeof(struct virtio_net_config); + dev_attr.get_config = vdpasim_net_get_config; vdpasim_dev = vdpasim_create(&dev_attr);
