On 2012-10-08 20:52, Anthony Liguori wrote: > Jan Kiszka <jan.kis...@siemens.com> writes: > >> On 2012-09-11 17:53, Jan Kiszka wrote: >>> Our one and only BIOS depends on a writable shadowed BIOS in the ISA >>> range. As we have no interface to control the write property, make that >>> region writable by default. >>> >>> Signed-off-by: Jan Kiszka <jan.kis...@siemens.com> >>> --- >>> >>> This unbreaks isapc for TCG, and keep it working for KVM once it starts >>> supporting read-only memslots. >>> >>> hw/pc_sysfw.c | 13 +++++++++---- >>> 1 files changed, 9 insertions(+), 4 deletions(-) >>> >>> diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c >>> index b45f0ac..027d98a 100644 >>> --- a/hw/pc_sysfw.c >>> +++ b/hw/pc_sysfw.c >>> @@ -136,6 +136,7 @@ static void old_pc_system_rom_init(MemoryRegion >>> *rom_memory) >>> { >>> char *filename; >>> MemoryRegion *bios, *isa_bios; >>> + void *isa_bios_ptr; >>> int bios_size, isa_bios_size; >>> int ret; >>> >>> @@ -167,19 +168,23 @@ static void old_pc_system_rom_init(MemoryRegion >>> *rom_memory) >>> g_free(filename); >>> } >>> >>> - /* map the last 128KB of the BIOS in ISA space */ >>> + /* Shadow the last 128KB of the BIOS in ISA space as RAM - >>> + * Seabios depends on this */ >>> isa_bios_size = bios_size; >>> if (isa_bios_size > (128 * 1024)) { >>> isa_bios_size = 128 * 1024; >>> } >>> isa_bios = g_malloc(sizeof(*isa_bios)); >>> - memory_region_init_alias(isa_bios, "isa-bios", bios, >>> - bios_size - isa_bios_size, isa_bios_size); >>> + memory_region_init_ram(isa_bios, "isa-bios", isa_bios_size); >>> + vmstate_register_ram_global(isa_bios); >>> memory_region_add_subregion_overlap(rom_memory, >>> 0x100000 - isa_bios_size, >>> isa_bios, >>> 1); >>> - memory_region_set_readonly(isa_bios, true); >>> + >>> + /* copy ISA rom image from top of the ROM */ >>> + isa_bios_ptr = memory_region_get_ram_ptr(isa_bios); >>> + rom_copy(isa_bios_ptr, (uint32_t)(-isa_bios_size), isa_bios_size); >>> >>> /* map all the bios at the top of memory */ >>> memory_region_add_subregion(rom_memory, >>> >> >> Ping. Or already queued? > > I've got it queued now. Thanks.
I'm withdrawing it: This breaks Windows 95 booting. For unknown reasons, this nice OS decided to overwrite the F-segment during boot. That is fine as long as it is properly protected. But it breaks under current KVM and with the patch above for the isapc. So we need a firmware interface to enable/disable write protection for this segment in isapc mode, specifically as that machine targets these old OSes. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux