[Qemu-devel] Forbid to pass lun 0 to iscsi driver

[Andrey Korolyov]

Hello,

As we will never pass LUN#0 as a storage lun, it would be better to
prohibit this at least in iscsi.c, otherwise it will result in an FPU
exception and emulator crash:

traps: qemu-system-x86[32430] trap divide error ip:7f1dab7b5073
sp:7f1d713e4ae0 error:0 in block-iscsi.so[7f1dab7b0000+8000]

    353 static bool is_request_lun_aligned(int64_t sector_num, int nb_sectors,
    354                                       IscsiLun *iscsilun)
    355 {
    356     if ((sector_num * BDRV_SECTOR_SIZE) % iscsilun->block_size ||
    357         (nb_sectors * BDRV_SECTOR_SIZE) % iscsilun->block_size) {

As far as I can see the LUN#0 can be thrown out on a top level, as one
will never use it directly as an iSCSI backend. Please correct me if
I`m wrong in this assumption.