When testing e1000 with the virt machine, e1000's I/O space cannot be accessed. Debugging shows that the I/O BAR (BAR1) is correctly written with address 0 plus I/O enable bit, but QEMU's "info pci" shows that:
Bus 0, device 1, function 0: Ethernet controller: PCI device 8086:100e ... BAR1: I/O at 0xffffffffffffffff [0x003e]. ... It turns out we should set pci_allow_0_address to true to allow 0 PCI address, otherwise pci_bar_address() treats such address as PCI_BAR_UNMAPPED. Signed-off-by: Bin Meng <bmeng...@gmail.com> --- hw/riscv/virt.c | 1 + 1 file changed, 1 insertion(+) diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c index 23f340d..411bef5 100644 --- a/hw/riscv/virt.c +++ b/hw/riscv/virt.c @@ -603,6 +603,7 @@ static void riscv_virt_machine_class_init(ObjectClass *oc, void *data) mc->init = riscv_virt_board_init; mc->max_cpus = 8; mc->default_cpu_type = VIRT_CPU; + mc->pci_allow_0_address = true; } static const TypeInfo riscv_virt_machine_typeinfo = { -- 2.7.4