Re: [Qemu-devel] [edk2-devel] [PATCH] q35: lpc: allow to lock down 128K RAM at default SMBASE address

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 11 Sep 2019 19:30:46 +0200
"Laszlo Ersek" <lersek@redhat.com> wrote:

> On 09/10/19 17:58, Igor Mammedov wrote:
> > On Mon, 9 Sep 2019 21:15:44 +0200
> > Laszlo Ersek <lersek@redhat.com> wrote:  
> 
> [...]
> 
> > It looks like fwcfg smi feature negotiation isn't reusable in this case.
> > I'd prefer not to add another device just for another SMI feature
> > negotiation/activation.  
> 
> I thought it could be a register on the new CPU hotplug controller that
> we're going to need anyway (if I understand correctly, at least).
If we don't have to 'park' hotplugged CPUs, then I don't see a need for
an extra controller.


> But:
> 
> > How about stealing reserved register from pci-host similar to your
> > extended TSEG commit (2f295167 q35/mch: implement extended TSEG sizes)?
> > (Looking into spec can (ab)use 0x58 or 0x59 register)  
> 
> Yes, that should work.
> 
> In fact, I had considered 0x58 / 0x59 when looking for unused registers
> for extended TSEG configuration:
> 
> http://mid.mail-archive.com/d8802612-0b11-776f-b209-53bbdaf67515@redhat.com
> 
> So I'm OK with this, thank you.
Thanks for the tip!
... patches with a stolen register are on the way to mail-list.