Currently virtio-blk, virtio-serial and virtio-scsi all crash on invalid migration streams because qemu_get_virtqueue_element has no way to detect and report mapping failures.
Not nice. Let's propagate mapping errors through qemu_get_virtqueue_element and fail migration instead. Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3888 Signed-off-by: Michael S. Tsirkin <[email protected]> --- include/hw/virtio/virtio.h | 2 +- hw/block/virtio-blk.c | 4 ++++ hw/char/virtio-serial-bus.c | 4 ++++ hw/scsi/virtio-scsi.c | 6 +++++ hw/virtio/virtio.c | 48 +++++++++++++++++++++++++++---------- 5 files changed, 50 insertions(+), 14 deletions(-) diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index c99cb19d88..27c5fe3a6b 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -320,7 +320,7 @@ bool virtqueue_rewind(VirtQueue *vq, unsigned int num); void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, unsigned int len, unsigned int idx); -void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem); +bool virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem); void *virtqueue_pop(VirtQueue *vq, size_t sz); unsigned int virtqueue_drop_all(VirtQueue *vq); void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz); diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 6b92066aff..cb6a276a82 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -1384,6 +1384,10 @@ static int virtio_blk_load_device(VirtIODevice *vdev, QEMUFile *f, } req = qemu_get_virtqueue_element(vdev, f, sizeof(VirtIOBlockReq)); + if (!req) { + error_report("Failed to restore virtio-blk request"); + return -EINVAL; + } virtio_blk_init_request(s, virtio_get_queue(vdev, vq_idx), req); WITH_QEMU_LOCK_GUARD(&s->rq_lock) { diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c index c1973f0248..0f56321cc7 100644 --- a/hw/char/virtio-serial-bus.c +++ b/hw/char/virtio-serial-bus.c @@ -763,6 +763,10 @@ static int fetch_active_ports_list(QEMUFile *f, port->elem = qemu_get_virtqueue_element(vdev, f, sizeof(VirtQueueElement)); + if (!port->elem) { + error_report("Failed to restore virtio-serial element"); + return -EINVAL; + } /* * Port was throttled on source machine. Let's diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c index 53c3c88460..8675afc6e1 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -18,6 +18,7 @@ #include "standard-headers/linux/virtio_ids.h" #include "hw/virtio/virtio-scsi.h" #include "migration/qemu-file-types.h" +#include "migration/qemu-file.h" #include "qemu/defer-call.h" #include "qemu/error-report.h" #include "qemu/iov.h" @@ -273,6 +274,11 @@ static void *virtio_scsi_load_request(QEMUFile *f, SCSIRequest *sreq) assert(n < vs->conf.num_queues); req = qemu_get_virtqueue_element(vdev, f, sizeof(VirtIOSCSIReq) + vs->cdb_size); + if (!req) { + error_report("Failed to restore virtio-scsi request"); + qemu_file_set_error(f, -EINVAL); + return NULL; + } virtio_scsi_init_req(s, vs->cmd_vqs[n], req); if (virtio_scsi_parse_req(req, sizeof(VirtIOSCSICmdReq) + vs->cdb_size, diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 2d33622daf..340bac2607 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -1676,36 +1676,55 @@ static void virtqueue_undo_map_desc(AddressSpace *as, } } -static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg, +static bool virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg, hwaddr *addr, unsigned int num_sg, bool is_write) { unsigned int i; hwaddr len; + DMADirection dir = is_write ? DMA_DIRECTION_FROM_DEVICE : + DMA_DIRECTION_TO_DEVICE; for (i = 0; i < num_sg; i++) { len = sg[i].iov_len; - sg[i].iov_base = dma_memory_map(vdev->dma_as, - addr[i], &len, is_write ? - DMA_DIRECTION_FROM_DEVICE : - DMA_DIRECTION_TO_DEVICE, - MEMTXATTRS_UNSPECIFIED); + sg[i].iov_base = dma_memory_map(vdev->dma_as, addr[i], &len, + dir, MEMTXATTRS_UNSPECIFIED); if (!sg[i].iov_base) { error_report("virtio: error trying to map MMIO memory"); - exit(1); + goto err_undo_map; } if (len != sg[i].iov_len) { error_report("virtio: unexpected memory split"); - exit(1); + dma_memory_unmap(vdev->dma_as, sg[i].iov_base, len, dir, 0); + goto err_undo_map; } } + return true; + +err_undo_map: + while (i-- > 0) { + dma_memory_unmap(vdev->dma_as, sg[i].iov_base, sg[i].iov_len, + dir, 0); + } + return false; } -void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem) +bool virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem) { - virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, elem->in_num, true); - virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, elem->out_num, - false); + if (!virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, + elem->in_num, true)) { + return false; + } + if (!virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, + elem->out_num, false)) { + for (unsigned int i = 0; i < elem->in_num; i++) { + dma_memory_unmap(vdev->dma_as, elem->in_sg[i].iov_base, + elem->in_sg[i].iov_len, + DMA_DIRECTION_FROM_DEVICE, 0); + } + return false; + } + return true; } static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num) @@ -2202,7 +2221,10 @@ void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz) qemu_get_be32s(f, &elem->ndescs); } - virtqueue_map(vdev, elem); + if (!virtqueue_map(vdev, elem)) { + g_free(elem); + return NULL; + } return elem; } -- MST
