The bochs-display mmio bar has some sub-regions with the actual hardware registers. What happens when the guest access something outside those regions depends on the archirecture. On x86 those reads succeed (and return 0xff I think). On risc-v qemu aborts.
This patch adds handlers for the parent region, to make the wanted behavior explicit and to make things consistent across architectures. v2: - use existing unassigned_io_ops. - also cover stdvga. Cc: Alistair Francis <alistai...@gmail.com> Signed-off-by: Gerd Hoffmann <kra...@redhat.com> --- hw/display/bochs-display.c | 4 ++-- hw/display/vga-pci.c | 8 ++++---- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/hw/display/bochs-display.c b/hw/display/bochs-display.c index 62085f9fc063..70eb619ef424 100644 --- a/hw/display/bochs-display.c +++ b/hw/display/bochs-display.c @@ -284,8 +284,8 @@ static void bochs_display_realize(PCIDevice *dev, Error **errp) memory_region_init_io(&s->qext, obj, &bochs_display_qext_ops, s, "qemu extended regs", PCI_VGA_QEXT_SIZE); - memory_region_init(&s->mmio, obj, "bochs-display-mmio", - PCI_VGA_MMIO_SIZE); + memory_region_init_io(&s->mmio, obj, &unassigned_io_ops, NULL, + "bochs-display-mmio", PCI_VGA_MMIO_SIZE); memory_region_add_subregion(&s->mmio, PCI_VGA_BOCHS_OFFSET, &s->vbe); memory_region_add_subregion(&s->mmio, PCI_VGA_QEXT_OFFSET, &s->qext); diff --git a/hw/display/vga-pci.c b/hw/display/vga-pci.c index b34632467399..6b9db86e363c 100644 --- a/hw/display/vga-pci.c +++ b/hw/display/vga-pci.c @@ -249,8 +249,8 @@ static void pci_std_vga_realize(PCIDevice *dev, Error **errp) /* mmio bar for vga register access */ if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_MMIO)) { - memory_region_init(&d->mmio, NULL, "vga.mmio", - PCI_VGA_MMIO_SIZE); + memory_region_init_io(&d->mmio, OBJECT(dev), &unassigned_io_ops, NULL, + "vga.mmio", PCI_VGA_MMIO_SIZE); if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_QEXT)) { qext = true; @@ -285,8 +285,8 @@ static void pci_secondary_vga_realize(PCIDevice *dev, Error **errp) s->con = graphic_console_init(DEVICE(dev), 0, s->hw_ops, s); /* mmio bar */ - memory_region_init(&d->mmio, OBJECT(dev), "vga.mmio", - PCI_VGA_MMIO_SIZE); + memory_region_init_io(&d->mmio, OBJECT(dev), &unassigned_io_ops, NULL, + "vga.mmio", PCI_VGA_MMIO_SIZE); if (d->flags & (1 << PCI_VGA_FLAG_ENABLE_QEXT)) { qext = true; -- 2.18.2