From 8edd56735baa7f58aa504d0f2c4ed6f893630cce Mon Sep 17 00:00:00 2001 From: Daniil Tatianin Date: Tue, 6 Sep 2022 10:31:11 +0300 Subject: vhost-user-blk: dynamically resize config space based on features Make vhost-user-blk backwards compatible when migrating from older VMs running with modern features turned off, the same way it was done for virtio-blk in 20764be0421c ("virtio-blk: set config size depending on the features enabled") It's currently impossible to migrate from an older VM with vhost-user-blk (with disable-legacy=off) because of errors like this: qemu-system-x86_64: get_pci_config_device: Bad config data: i=0x10 read: 41 device: 1 cmask: ff wmask: 80 w1cmask:0 qemu-system-x86_64: Failed to load PCIDevice:config qemu-system-x86_64: Failed to load virtio-blk:virtio qemu-system-x86_64: error while loading state for instance 0x0 of device '0000:00:05.0:00.0:02.0/virtio-blk' qemu-system-x86_64: load of migration failed: Invalid argument This is caused by the newer (destination) VM requiring a bigger BAR0 alignment because it has to cover a bigger configuration space, which isn't actually needed since those additional config fields are not active (write-zeroes/discard). Signed-off-by: Daniil Tatianin Reviewed-by: Raphael Norwitz Message-Id: <20220906073111.353245-6-d-tatianin@yandex-team.ru> Reviewed-by: Raphael Norwitz Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/block/vhost-user-blk.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'hw/block/vhost-user-blk.c') diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c index aa4831f27a..84902dde17 100644 --- a/hw/block/vhost-user-blk.c +++ b/hw/block/vhost-user-blk.c @@ -23,6 +23,7 @@ #include "hw/qdev-core.h" #include "hw/qdev-properties.h" #include "hw/qdev-properties-system.h" +#include "hw/virtio/virtio-blk-common.h" #include "hw/virtio/vhost.h" #include "hw/virtio/vhost-user-blk.h" #include "hw/virtio/virtio.h" @@ -63,7 +64,7 @@ static void vhost_user_blk_update_config(VirtIODevice *vdev, uint8_t *config) /* Our num_queues overrides the device backend */ virtio_stw_p(vdev, &s->blkcfg.num_queues, s->num_queues); - memcpy(config, &s->blkcfg, sizeof(struct virtio_blk_config)); + memcpy(config, &s->blkcfg, vdev->config_len); } static void vhost_user_blk_set_config(VirtIODevice *vdev, const uint8_t *config) @@ -92,12 +93,12 @@ static int vhost_user_blk_handle_config_change(struct vhost_dev *dev) { int ret; struct virtio_blk_config blkcfg; + VirtIODevice *vdev = dev->vdev; VHostUserBlk *s = VHOST_USER_BLK(dev->vdev); Error *local_err = NULL; ret = vhost_dev_get_config(dev, (uint8_t *)&blkcfg, - sizeof(struct virtio_blk_config), - &local_err); + vdev->config_len, &local_err); if (ret < 0) { error_report_err(local_err); return ret; @@ -106,7 +107,7 @@ static int vhost_user_blk_handle_config_change(struct vhost_dev *dev) /* valid for resize only */ if (blkcfg.capacity != s->blkcfg.capacity) { s->blkcfg.capacity = blkcfg.capacity; - memcpy(dev->vdev->config, &s->blkcfg, sizeof(struct virtio_blk_config)); + memcpy(dev->vdev->config, &s->blkcfg, vdev->config_len); virtio_notify_config(dev->vdev); } @@ -448,7 +449,7 @@ static int vhost_user_blk_realize_connect(VHostUserBlk *s, Error **errp) assert(s->connected); ret = vhost_dev_get_config(&s->dev, (uint8_t *)&s->blkcfg, - sizeof(struct virtio_blk_config), errp); + s->parent_obj.config_len, errp); if (ret < 0) { qemu_chr_fe_disconnect(&s->chardev); vhost_dev_cleanup(&s->dev); @@ -463,6 +464,7 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp) ERRP_GUARD(); VirtIODevice *vdev = VIRTIO_DEVICE(dev); VHostUserBlk *s = VHOST_USER_BLK(vdev); + size_t config_size; int retries; int i, ret; @@ -493,8 +495,9 @@ static void vhost_user_blk_device_realize(DeviceState *dev, Error **errp) return; } - virtio_init(vdev, VIRTIO_ID_BLOCK, - sizeof(struct virtio_blk_config)); + config_size = virtio_get_config_size(&virtio_blk_cfg_size_params, + vdev->host_features); + virtio_init(vdev, VIRTIO_ID_BLOCK, config_size); s->virtqs = g_new(VirtQueue *, s->num_queues); for (i = 0; i < s->num_queues; i++) { -- cgit v1.2.3