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 10:07:31AM +0100, Daniel P. Berrangé 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.
> 
> Does that really matter though ? By its very nature the 'Version'
> field in SMBIOS is expected to change if you alter something about
> the hardware. If guests OS don't want to be exposed to changes in
> SMBIOS they would be using a fixed machine type, not the variable
> "pc" type that continually changes.
> 
> We could put padding in the string if we want to avoid BIOS table
> layout changes.
> 
> Having version change though feels like it is working as intended
> for the semantics of these Version: fields in BIOS.

Michael, do you have additional info on the original motivation
for suggesting this change and why do you consider it a bug?
(I don't have any concrete examples to justify the change)

-- 
Eduardo