Re: [Qemu-devel] [PATCH for-3.0] pc: Use "3.0+" constant as default SMBIOS version

[Eduardo Habkost <ehabkost@redhat.com>]

On Tue, Jul 10, 2018 at 02:54:12AM +0300, Michael S. Tsirkin wrote:
> On Mon, Jul 09, 2018 at 05:37:31PM -0300, Eduardo Habkost wrote:
> > Every time we create new PC machine-types in QEMU, the defaults
> > for SMBIOS fields change unnecessarily because the version field
> > defaults to MachineClass::name.
> > 
> > This can cause unexpected side-effects, like triggering license
> > reactivation on guest software, or changing the VM memory layout
> > because of BIOS table size changes.
> > 
> > Change the SMBIOS version string for pc-*-3.0 to "3.0+" to avoid
> > doing this on every QEMU release, and keep compatible version
> > strings on older machine-types using a new
> > MachineClass::smbios_version field.
> > 
> > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> > ---
> > I just noticed that we started using mc->name on arm/virt since
> > commit dfadc3bfb458efefb72e13a57b62f138c464a577.
> > Should arm/virt start using "3.0+" too?
> > ---
> >  include/hw/i386/pc.h | 3 +++
> >  hw/i386/pc.c         | 1 +
> >  hw/i386/pc_piix.c    | 5 +++--
> >  hw/i386/pc_q35.c     | 3 ++-
> >  4 files changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> > index 4d99d69681..aea0fcaadb 100644
> > --- a/include/hw/i386/pc.h
> > +++ b/include/hw/i386/pc.h
> > @@ -134,6 +134,9 @@ struct PCMachineClass {
> >  
> >      /* use DMA capable linuxboot option rom */
> >      bool linuxboot_dma_enabled;
> > +
> > +    /* Version field for SMBIOS Type 1, Type 2, Type 3, and Type 4 structs */
> > +    const char *smbios_version;
> >  };
> >  
> >  #define TYPE_PC_MACHINE "generic-pc-machine"
> > diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> > index 50d5553991..47877e7071 100644
> > --- a/hw/i386/pc.c
> > +++ b/hw/i386/pc.c
> > @@ -2379,6 +2379,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
> >      pcmc->acpi_data_size = 0x20000 + 0x8000;
> >      pcmc->save_tsc_khz = true;
> >      pcmc->linuxboot_dma_enabled = true;
> > +    pcmc->smbios_version = "3.0+";
> >      assert(!mc->get_hotplug_handler);
> >      mc->get_hotplug_handler = pc_get_hotpug_handler;
> >      mc->cpu_index_to_instance_props = pc_cpu_index_to_props;
> 
> I suspect 3.00 is cleaner for tools that happen to
> parse the version as a numeral as it always was in the past,
> even if it's not exact.

It was never a numeral.  It was "pc-q35-X.Y" or "pc-i440fx-X.Y".

-- 
Eduardo