Re: [PATCH v2] pc: q35: Bump max_cpus to 1024

[Gerd Hoffmann]

  Hi,

> > I suspect smbios 3.0 (64-bit entry point) is already supported.
> > 
> > With current qemu and all the smbios fixes in the last cycle, perhaps this 
> > is
> > mainly just setting smbios_entry_point_type to SMBIOS_ENTRY_POINT_TYPE_64 if
> > MachineState::smp::max_cpus is bigger than 720 (e.g. in pc_q35_init()?)
> 
> The need for the 64-bit entry point depends on a combination of RAM config
> and CPU count. IMHO we need to unconditionally switch the latest machine
> types to use the 64-bit entry point by default, rather than trying to infer
> some special condition to dynamically change on the fly.
> 
> Before doing that we need confirmation that our firmware builds in qemu.git
> (SeaBIOS and EDK2) will be happy with the 64-bit EP. I suspect they should
> be fine by now, but I've CC'd Gerd to confirm.

edk2 is ready for quite a while (years).

seabios was lagging behind for a long time, but smbios 3.0 support
finally landed early last year, in release 1.16.0 (qemu 7.0).

So, yes, firmware-wise we are ready to flip the default now.

take care,
  Gerd