Re: [PATCH] smbios: entry-point-type option

[Eduardo Habkost]

On Wed, Dec 09, 2020 at 09:42:25AM +0000, Daniel P. Berrangé wrote:
> On Tue, Dec 08, 2020 at 04:20:23PM -0500, Eduardo Habkost wrote:
> > Add command-line option that lets the SMBIOS entry point type to
> > be configured.
> > 
> > SMBIOS 3.0 support is necessary to allow us to support more
> > than 720 VCPUs in x86_64, due to SMBIOS 2.1 table size limits.
> > 
> > Note that it's still up to firmware to decide whether to generate
> > SMBIOS 2.1 and/or 3.0 entry points for the guest, using the
> > information contained in etc/smbios/smbios-anchor.  OVMF, for
> > example, is able to generate both entry points, depending on the
> > value of PcdSmbiosEntryPointProvideMethod.
> > 
> > The SMBIOS 3.0 entry point won't be enabled by default because it
> > is not supported yet by Seabios.  This may be changed once
> > Seabios starts supporting SMBIOS 3.0 entry points.
> > 
> > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> > ---
> > Laszlo, Philippe: do you know how exactly the value of
> > PcdSmbiosEntryPointProvideMethod is chosen when running OVMF?
> 
> Laszlo proides alot of detail in my original proposal for
> selecting SMBIOS entry point here:
> 
> https://lists.gnu.org/archive/html/qemu-devel/2020-09/msg03347.html

Thanks!

> 
[...]
> > diff --git a/qemu-options.hx b/qemu-options.hx
> > index 104632ea34..d2a973f8a7 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -2294,7 +2294,9 @@ DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,
> >      "                specify SMBIOS type 11 fields\n"
> >      "-smbios 
> > type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n"
> >      "               [,asset=str][,part=str][,speed=%d]\n"
> > -    "                specify SMBIOS type 17 fields\n",
> > +    "                specify SMBIOS type 17 fields\n"
> > +    "-smbios entry-point-type=2.1|3.0\n"
> > +    "                specify SMBIOS entry point type\n",
> 
> My previous patch:
> 
>   https://lists.gnu.org/archive/html/qemu-devel/2020-09/msg03027.html
> 
> exposed the entry point version as a property on the PC machine
> rather than the -smbios arg, principally because it is the machin
> setup code that currently defines what version is used via the calls
> to smbios_set_defaults().
> 
> IIUC from Laszlo's reply,  SMBIOS 2.1 is not valid for AArch64
> at all - they only support 3.0.  So there's a small benefit from
> configuring this against the PC machine types, because it prevents
> ability to select 2.1 for ARM SMBIOS which would be invalid.

Good point.  It would also make it easier to change the machine
type default in the future.

I will submit something based on your patches, instead.

-- 
Eduardo