Re: [SeaBIOS] [PATCH] vcpu hotplug: Setup vcpu add/remove infrastructure

[Gleb Natapov]

On Sat, Jan 30, 2010 at 12:52:54AM +0800, Liu, Jinsong wrote:
> Gleb Natapov wrote:
> > On Fri, Jan 29, 2010 at 11:34:24PM +0800, Liu, Jinsong wrote:
> > > Gleb Natapov wrote:
> > > > On Thu, Jan 28, 2010 at 10:54:48PM +0800, Liu, Jinsong wrote:
> > > > > Connor and Gleb,
> > > > >
> > > > > I updated my patch according to our discussion:
> > > > > simplify scan loop according to 'maxvcpus';
> > > > > remove unecessary global variables;
> > > > > change hardcode address to bios use only area '0x514';
> > > > > remove simple _PR scope from ssdt;
> > > >
> > > > I still don't see that ACPI NVS issue is addressed.
> > >
> > > Gleb,
> > >
> > > I'm not quite sure Win7 BSOD issue you mentioned last email, anyway
> > > I update my patch, define ACPI NVS per my understanding.
> >
> > You need checked build of Windows 7. This is not regular Win7 this is
> > debug version that you can download from MSDN. Here is the bug report
> > about the crash:
> > http://sourceforge.net/tracker/?func=detail&aid=2902983&group_id=180...
> >
> > Anyway according to ACPI spec ACPI DATA area can be reused by an OS
> > after reading ACPI tables so it is wrong to access this memory after
> > an OS boot.
>
> Yes, it's safer to define ACPI NVS, although it's bios use only area.

APCI DATA is explicitly not defined by ACPI spec as "bios use only
area".

[PATCH] vcpu hotplug: Setup vcpu add/remove infrastructure

[Liu, Jinsong]

Gleb Natapov wrote:
> On Sat, Jan 30, 2010 at 12:52:54AM +0800, Liu, Jinsong wrote:
> > Gleb Natapov wrote:
> > > On Fri, Jan 29, 2010 at 11:34:24PM +0800, Liu, Jinsong wrote:
> > > > Gleb Natapov wrote:
> > > > > On Thu, Jan 28, 2010 at 10:54:48PM +0800, Liu, Jinsong wrote:
> > > > > > Connor and Gleb,
> > > > > >
> > > > > > I updated my patch according to our discussion:
> > > > > > simplify scan loop according to 'maxvcpus';
> > > > > > remove unecessary global variables;
> > > > > > change hardcode address to bios use only area '0x514';
> > > > > > remove simple _PR scope from ssdt;
> > > > >
> > > > > I still don't see that ACPI NVS issue is addressed.
> > > >
> > > > Gleb,
> > > >
> > > > I'm not quite sure Win7 BSOD issue you mentioned last email, anyway
> > > > I update my patch, define ACPI NVS per my understanding.
> > >
> > > You need checked build of Windows 7. This is not regular Win7 this
> > > is debug version that you can download from MSDN. Here is the bug
> > > report about the crash:
> > > http://sourceforge.net/tracker/?func=detail&aid=2902983&group_id=180...
> > >
> > > Anyway according to ACPI spec ACPI DATA area can be reused by an OS
> > > after reading ACPI tables so it is wrong to access this memory
> > > after an OS boot.
> >
> > Yes, it's safer to define ACPI NVS, although it's bios use only area.
>
> APCI DATA is explicitly not defined by ACPI spec as "bios use only
> area".

Yes, it's not defined by ACPI spec, but from default x86 memory layout, refer to Documentation/x86/boot.txt:
001000  +------------------------+
        |  Reserved for MBR/BIOS |
000800  +------------------------+
        |  Typically used by MBR |
000600  +------------------------+
        |  BIOS use only         |
000000  +------------------------+

Thanks,
Jinsong