On Wed, 20 May 2020 15:19:55 +0200
Gerd Hoffmann <kra...@redhat.com> wrote:
> Looks like the logiv was copied over from q35.
>
> q35 does this for backward compatibility, there is no reason to do this
> on microvm though. So split @ 2G unconditionally.
not related to your ACPI rework, but just an idea for future of microvm
I wonder if we should carry over all this fixed RAM layout legacy from pc/q35
with a bunch of knobs to tweak it (along with complicated logic).
Can we just re-use pc-dimms for main RAM and let user specify RAM layout the
way they wish?
> Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
> ---
> hw/i386/microvm.c | 16 +---------------
> 1 file changed, 1 insertion(+), 15 deletions(-)
>
> diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
> index 867d3d652145..b8f0d3283758 100644
> --- a/hw/i386/microvm.c
> +++ b/hw/i386/microvm.c
> @@ -170,23 +170,9 @@ static void microvm_memory_init(MicrovmMachineState *mms)
> MemoryRegion *ram_below_4g, *ram_above_4g;
> MemoryRegion *system_memory = get_system_memory();
> FWCfgState *fw_cfg;
> - ram_addr_t lowmem;
> + ram_addr_t lowmem = 0x80000000; /* 2G */
> int i;
>
> - /*
> - * Check whether RAM fits below 4G (leaving 1/2 GByte for IO memory
> - * and 256 Mbytes for PCI Express Enhanced Configuration Access Mapping
> - * also known as MMCFG).
> - * If it doesn't, we need to split it in chunks below and above 4G.
> - * In any case, try to make sure that guest addresses aligned at
> - * 1G boundaries get mapped to host addresses aligned at 1G boundaries.
> - */
> - if (machine->ram_size >= 0xb0000000) {
> - lowmem = 0x80000000;
> - } else {
> - lowmem = 0xb0000000;
> - }
> -
> /*
> * Handle the machine opt max-ram-below-4g. It is basically doing
> * min(qemu limit, user limit).
