On Tue, Apr 30, 2024 at 5:39 PM Philippe Mathieu-Daudé
<phi...@linaro.org> wrote:
> I'm still not convinced we need a migration back compat for this...
It's absolutely needed,
memory_region_init_ram(isa_bios, NULL, "isa-bios", isa_bios_size,
&error_fatal);
will register a RAM region for migration, and when the destination
receives data from an older source, it will not find it it will fail.
On the other hand, if migrating backwards isa-bios will not be
populated and the guest may fail after reboot.
Paolo
> > diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> > index 82d37cb376..ac88ad4eb9 100644
> > --- a/hw/i386/pc_sysfw.c
> > +++ b/hw/i386/pc_sysfw.c
> > @@ -135,6 +135,7 @@ static void pc_system_flash_map(PCMachineState *pcms,
> > MemoryRegion *rom_memory)
> > {
> > X86MachineState *x86ms = X86_MACHINE(pcms);
> > + PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
> > hwaddr total_size = 0;
> > int i;
> > BlockBackend *blk;
> > @@ -184,7 +185,12 @@ static void pc_system_flash_map(PCMachineState *pcms,
> >
> > if (i == 0) {
> > flash_mem = pflash_cfi01_get_memory(system_flash);
> > - pc_isa_bios_init(&x86ms->isa_bios, rom_memory, flash_mem);
> > + if (pcmc->isa_bios_alias) {
> > + x86_isa_bios_init(&x86ms->isa_bios, rom_memory, flash_mem,
> > + true);
> > + } else {
> > + pc_isa_bios_init(&x86ms->isa_bios, rom_memory, flash_mem);
> > + }
> >
> > /* Encrypt the pflash boot ROM */
> > if (sev_enabled()) {
>
