From 20764be0421c3d5d97f84219d55a412f3cd2ca9a Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Thu, 21 Feb 2019 11:33:09 +0100 Subject: [PATCH] virtio-blk: set config size depending on the features enabled Starting from DISABLE and WRITE_ZEROES features, we use an array of VirtIOFeature (as virtio-net) to properly set the config size depending on the features enabled. Reviewed-by: Stefan Hajnoczi Signed-off-by: Stefano Garzarella Message-id: 20190221103314.58500-6-sgarzare@redhat.com Message-Id: <20190221103314.58500-6-sgarzare@redhat.com> Signed-off-by: Stefan Hajnoczi --- hw/block/virtio-blk.c | 31 +++++++++++++++++++++++++------ include/hw/virtio/virtio-blk.h | 1 + 2 files changed, 26 insertions(+), 6 deletions(-) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index f7cd322811..8798d13bc4 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -28,9 +28,28 @@ #include "hw/virtio/virtio-bus.h" #include "hw/virtio/virtio-access.h" -/* We don't support discard yet, hide associated config fields. */ +/* Config size before the discard support (hide associated config fields) */ #define VIRTIO_BLK_CFG_SIZE offsetof(struct virtio_blk_config, \ max_discard_sectors) +/* + * Starting from the discard feature, we can use this array to properly + * set the config size depending on the features enabled. + */ +static VirtIOFeature feature_sizes[] = { + {.flags = 1ULL << VIRTIO_BLK_F_DISCARD, + .end = virtio_endof(struct virtio_blk_config, discard_sector_alignment)}, + {.flags = 1ULL << VIRTIO_BLK_F_WRITE_ZEROES, + .end = virtio_endof(struct virtio_blk_config, write_zeroes_may_unmap)}, + {} +}; + +static void virtio_blk_set_config_size(VirtIOBlock *s, uint64_t host_features) +{ + s->config_size = MAX(VIRTIO_BLK_CFG_SIZE, + virtio_feature_get_config_size(feature_sizes, host_features)); + + assert(s->config_size <= sizeof(struct virtio_blk_config)); +} static void virtio_blk_init_request(VirtIOBlock *s, VirtQueue *vq, VirtIOBlockReq *req) @@ -763,8 +782,7 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) blkcfg.alignment_offset = 0; blkcfg.wce = blk_enable_write_cache(s->blk); virtio_stw_p(vdev, &blkcfg.num_queues, s->conf.num_queues); - memcpy(config, &blkcfg, VIRTIO_BLK_CFG_SIZE); - QEMU_BUILD_BUG_ON(VIRTIO_BLK_CFG_SIZE > sizeof(blkcfg)); + memcpy(config, &blkcfg, s->config_size); } static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config) @@ -772,8 +790,7 @@ static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config) VirtIOBlock *s = VIRTIO_BLK(vdev); struct virtio_blk_config blkcfg; - memcpy(&blkcfg, config, VIRTIO_BLK_CFG_SIZE); - QEMU_BUILD_BUG_ON(VIRTIO_BLK_CFG_SIZE > sizeof(blkcfg)); + memcpy(&blkcfg, config, s->config_size); aio_context_acquire(blk_get_aio_context(s->blk)); blk_set_enable_write_cache(s->blk, blkcfg.wce != 0); @@ -956,7 +973,9 @@ static void virtio_blk_device_realize(DeviceState *dev, Error **errp) return; } - virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK, VIRTIO_BLK_CFG_SIZE); + virtio_blk_set_config_size(s, s->host_features); + + virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK, s->config_size); s->blk = conf->conf.blk; s->rq = NULL; diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index f7345b0511..7877ae67ae 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -56,6 +56,7 @@ typedef struct VirtIOBlock { bool dataplane_started; struct VirtIOBlockDataPlane *dataplane; uint64_t host_features; + size_t config_size; } VirtIOBlock; typedef struct VirtIOBlockReq { -- GitLab