Hi: background: I run virtio_net and virt_con in the lastest version, it is run OK, but I try to add another virito blk, I meet run error below: "Unhandled offset of 0x400 of size 4, reading Assertion failed: !"panic" (/home/yadong.li/seL4_vm_11/sel4_horizon/camkes-arm-vm/projects/seL4_projects_libs/libsel4vmmplatsupport/src/drivers/virtio_emul.c: emul_io_in: 71)" I add print on my enviornmen, found: ********************start[0x1000], end[0x1400] /*net*/ ********************start[0x1400], end[0x1800] /*con*/ ********************start[0x1800], end[0x1c00] /*blk*/ ---------------------------virtio_con_io_in, con = 0x55f3238, offset = 0x400[0x1800:0x1400] port_no:1800 should belong "blk", but it recongnize as belong "con"(con may be not use the offset 0 feature), the boundary may be have some problem the function: static int alloc_free_io_port_range(vmm_io_port_list_t *io_list, ioport_range_t *io_range) { uint16_t free_port_addr = io_list->alloc_addr; if (free_port_addr + io_range->size < free_port_addr) { /* Possible overflow */ return -1; } io_list->alloc_addr += io_range->size; io_range->start = free_port_addr; io_range->end = free_port_addr + io_range->size; return 0; } I think "io_range->end = free_port_addr + io_range->size;" should change to "io_range->end = free_port_addr + io_range->size - 1;" ? Thank you very much!