From d74c30c81159d703fb4e1caa0ec6772ff89dd02f Mon Sep 17 00:00:00 2001 From: Daniil Tatianin Date: Tue, 6 Sep 2022 10:31:07 +0300 Subject: virtio: introduce VirtIOConfigSizeParams & virtio_get_config_size This is the first step towards moving all device config size calculation logic into the virtio core code. In particular, this adds a struct that contains all the necessary information for common virtio code to be able to calculate the final config size for a device. This is expected to be used with the new virtio_get_config_size helper, which calculates the final length based on the provided host features. This builds on top of already existing code like VirtIOFeature and virtio_feature_get_config_size(), but adds additional fields, as well as sanity checking so that device-specifc code doesn't have to duplicate it. An example usage would be: static const VirtIOFeature dev_features[] = { {.flags = 1ULL << FEATURE_1_BIT, .end = endof(struct virtio_dev_config, feature_1)}, {.flags = 1ULL << FEATURE_2_BIT, .end = endof(struct virtio_dev_config, feature_2)}, {} }; static const VirtIOConfigSizeParams dev_cfg_size_params = { .min_size = DEV_BASE_CONFIG_SIZE, .max_size = sizeof(struct virtio_dev_config), .feature_sizes = dev_features }; // code inside my_dev_device_realize() size_t config_size = virtio_get_config_size(&dev_cfg_size_params, host_features); virtio_init(vdev, VIRTIO_ID_MYDEV, config_size); Currently every device is expected to write its own boilerplate from the example above in device_realize(), however, the next step of this transition is moving VirtIOConfigSizeParams into VirtioDeviceClass, so that it can be done automatically by the virtio initialization code. All of the users of virtio_feature_get_config_size have been converted to use virtio_get_config_size so it's no longer needed and is removed with this commit. Signed-off-by: Daniil Tatianin Message-Id: <20220906073111.353245-2-d-tatianin@yandex-team.ru> Reviewed-by: Raphael Norwitz Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'hw/virtio/virtio.c') diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 97a6307..2cc1d7d 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -3006,11 +3006,12 @@ int virtio_set_features(VirtIODevice *vdev, uint64_t val) return ret; } -size_t virtio_feature_get_config_size(const VirtIOFeature *feature_sizes, - uint64_t host_features) +size_t virtio_get_config_size(const VirtIOConfigSizeParams *params, + uint64_t host_features) { - size_t config_size = 0; - int i; + size_t config_size = params->min_size; + const VirtIOFeature *feature_sizes = params->feature_sizes; + size_t i; for (i = 0; feature_sizes[i].flags != 0; i++) { if (host_features & feature_sizes[i].flags) { @@ -3018,6 +3019,7 @@ size_t virtio_feature_get_config_size(const VirtIOFeature *feature_sizes, } } + assert(config_size <= params->max_size); return config_size; } -- cgit v1.1