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X-Received-From: 134.134.136.65 Subject: [Qemu-devel] [PATCH v4] virtio-blk: set correct config size for the host driver X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ldoktor@redhat.com, mst@redhat.com, dgilbert@redhat.com, stefanha@redhat.com, changpeng.liu@intel.com, sgarzare@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Commit caa1ee43 "vhost-user-blk: add discard/write zeroes features support" added fields to struct virtio_blk_config. This changes the size of the config space and breaks migration from QEMU 3.1 and older: qemu-system-ppc64: get_pci_config_device: Bad config data: i=3D0x10 read: 4= 1 device: 1 cmask: ff wmask: 80 w1cmask:0 qemu-system-ppc64: Failed to load PCIDevice:config qemu-system-ppc64: Failed to load virtio-blk:virtio qemu-system-ppc64: error while loading state for instance 0x0 of device 'pc= i@800000020000000:01.0/virtio-blk' qemu-system-ppc64: load of migration failed: Invalid argument Since virtio-blk doesn't support the "discard" and "write zeroes" features, it shouldn't even expose the associated fields in the config space actually. Just include all fields up to num_queues to match QEMU 3.1 and older. Signed-off-by: Changpeng Liu Reviewed-by: Greg Kurz Reviewed-by: Michael S. Tsirkin Tested-by: Greg Kurz --- hw/block/virtio-blk.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 9a87b3b..6fce9c7 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -28,6 +28,10 @@ #include "hw/virtio/virtio-bus.h" #include "hw/virtio/virtio-access.h" =20 +/* We don't support discard yet, hide associated config fields. */ +#define VIRTIO_BLK_CFG_SIZE offsetof(struct virtio_blk_config, \ + max_discard_sectors) + static void virtio_blk_init_request(VirtIOBlock *s, VirtQueue *vq, VirtIOBlockReq *req) { @@ -761,7 +765,8 @@ static void virtio_blk_update_config(VirtIODevice *vdev= , uint8_t *config) blkcfg.alignment_offset =3D 0; blkcfg.wce =3D blk_enable_write_cache(s->blk); virtio_stw_p(vdev, &blkcfg.num_queues, s->conf.num_queues); - memcpy(config, &blkcfg, sizeof(struct virtio_blk_config)); + memcpy(config, &blkcfg, VIRTIO_BLK_CFG_SIZE); + QEMU_BUILD_BUG_ON(VIRTIO_BLK_CFG_SIZE > sizeof(blkcfg)); } =20 static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *confi= g) @@ -769,7 +774,8 @@ static void virtio_blk_set_config(VirtIODevice *vdev, c= onst uint8_t *config) VirtIOBlock *s =3D VIRTIO_BLK(vdev); struct virtio_blk_config blkcfg; =20 - memcpy(&blkcfg, config, sizeof(blkcfg)); + memcpy(&blkcfg, config, VIRTIO_BLK_CFG_SIZE); + QEMU_BUILD_BUG_ON(VIRTIO_BLK_CFG_SIZE > sizeof(blkcfg)); =20 aio_context_acquire(blk_get_aio_context(s->blk)); blk_set_enable_write_cache(s->blk, blkcfg.wce !=3D 0); @@ -952,8 +958,7 @@ static void virtio_blk_device_realize(DeviceState *dev,= Error **errp) return; } =20 - virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK, - sizeof(struct virtio_blk_config)); + virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK, VIRTIO_BLK_CFG_SIZE); =20 s->blk =3D conf->conf.blk; s->rq =3D NULL; --=20 1.9.3