Windows XP does write to sector 0 during installation and prints mysterious error if write fails. Interestingly if write drops data, but returns OK to Windows installer installation proceed without complains and completes successfully.
Signed-off-by: Gleb Natapov gleb@redhat.com --- v1->v2 Call to vring_add_buf() should be different for write and read.
diff --git a/src/virtio-blk.c b/src/virtio-blk.c index 74af488..9835267 100644 --- a/src/virtio-blk.c +++ b/src/virtio-blk.c @@ -26,13 +26,13 @@ struct virtiodrive_s { };
static int -virtio_blk_read(struct disk_op_s *op) +virtio_blk_op(struct disk_op_s *op, int write) { struct virtiodrive_s *vdrive_g = container_of(op->drive_g, struct virtiodrive_s, drive); struct vring_virtqueue *vq = GET_GLOBAL(vdrive_g->vq); struct virtio_blk_outhdr hdr = { - .type = VIRTIO_BLK_T_IN, + .type = write ? VIRTIO_BLK_T_OUT : VIRTIO_BLK_T_IN, .ioprio = 0, .sector = op->lba, }; @@ -53,7 +53,10 @@ virtio_blk_read(struct disk_op_s *op) };
/* Add to virtqueue and kick host */ - vring_add_buf(vq, sg, 1, 2, 0, 0); + if (write) + vring_add_buf(vq, sg, 2, 1, 0, 0); + else + vring_add_buf(vq, sg, 1, 2, 0, 0); vring_kick(GET_GLOBAL(vdrive_g->ioaddr), vq, 1);
/* Wait for reply */ @@ -78,9 +81,10 @@ process_virtio_op(struct disk_op_s *op) return 0; switch (op->command) { case CMD_READ: - return virtio_blk_read(op); - case CMD_FORMAT: + return virtio_blk_op(op, 0); case CMD_WRITE: + return virtio_blk_op(op, 1); + case CMD_FORMAT: return DISK_RET_EWRITEPROTECT; case CMD_RESET: case CMD_ISREADY: -- Gleb.