Re: [PATCH v6 12/15] hw/pci: Use -1 as a default value for rombar

[Markus Armbruster <armbru@redhat.com>]

Akihiko Odaki <akihiko.odaki@daynix.com> writes:

> Currently there is no way to distinguish the case that rombar is
> explicitly specified as 1 and the case that rombar is not specified.
>
> Set rombar -1 by default to distinguish these cases just as it is done
> for addr and romsize. It was confirmed that changing the default value
> to -1 will not change the behavior by looking at occurences of rom_bar.
>
> $ git grep -w rom_bar
> hw/display/qxl.c:328:    QXLRom *rom = memory_region_get_ram_ptr(&d->rom_bar);
> hw/display/qxl.c:431:    qxl_set_dirty(&qxl->rom_bar, 0, qxl->rom_size);
> hw/display/qxl.c:1048:    QXLRom *rom = memory_region_get_ram_ptr(&qxl->rom_bar);
> hw/display/qxl.c:2131:    memory_region_init_rom(&qxl->rom_bar, OBJECT(qxl), "qxl.vrom",
> hw/display/qxl.c:2154: PCI_BASE_ADDRESS_SPACE_MEMORY, &qxl->rom_bar);
> hw/display/qxl.h:101:    MemoryRegion       rom_bar;
> hw/pci/pci.c:74:    DEFINE_PROP_UINT32("rombar",  PCIDevice, rom_bar, 1),
> hw/pci/pci.c:2329:    if (!pdev->rom_bar) {
> hw/vfio/pci.c:1019:    if (vdev->pdev.romfile || !vdev->pdev.rom_bar) {
> hw/xen/xen_pt_load_rom.c:29:    if (dev->romfile || !dev->rom_bar) {
> include/hw/pci/pci_device.h:150:    uint32_t rom_bar;
>
> rom_bar refers to a different variable in qxl. It is only tested if
> the value is 0 or not in the other places.

Makes me wonder why it's uint32_t.  Not this patch's problem.

> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>  hw/pci/pci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 54b375da2d26..909c5b3ee4ee 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -71,7 +71,7 @@ static Property pci_props[] = {
>      DEFINE_PROP_PCI_DEVFN("addr", PCIDevice, devfn, -1),
>      DEFINE_PROP_STRING("romfile", PCIDevice, romfile),
>      DEFINE_PROP_UINT32("romsize", PCIDevice, romsize, -1),
> -    DEFINE_PROP_UINT32("rombar",  PCIDevice, rom_bar, 1),
> +    DEFINE_PROP_UINT32("rombar",  PCIDevice, rom_bar, -1),
>      DEFINE_PROP_BIT("multifunction", PCIDevice, cap_present,
>                      QEMU_PCI_CAP_MULTIFUNCTION_BITNR, false),
>      DEFINE_PROP_BIT("x-pcie-lnksta-dllla", PCIDevice, cap_present,