Re: [Xen-devel] Workings/effectiveness of the xen-acpi-processor driver

[Boris Ostrovsky <boris.ostrovsky@xxxxxxx>]

On 05/03/2012 11:46 AM, Konrad Rzeszutek Wilk wrote:
> On Thu, May 03, 2012 at 04:47:46PM +0200, Stefan Bader wrote:
> > On 03.05.2012 14:58, Stefan Bader wrote:
> >
> > > > > > > So this shoudl solve the problem for the bootup processor.
> > > > > > > > -boris
> > > > > > > >
> > > > > > > >
> > > > > > > > > +    };
> > > > > > > > > +    int ret = 0;
> > > > > > > > > +
> > > > > > > > > +    /* Shouldn't need this as APIC is turned off for PV, and we only
> > > > > > > > > +     * get called on the bootup processor. But just in case. */
> > > > > > > > > +    if (!xen_initial_domain() || smp_processor_id())
> > > > > > > > > +        return 0;
> > > > > > > > > +
> > > > > > > > > +    if (reg == APIC_LVR)
> > > > > > > > > +        return 0x10;
> > > > > > > > > +
> > > > > > > > > +    if (reg != APIC_ID)
> > > > > > > > > +        return 0;
> > > > > > > > > +
> > > > > > > > > +    ret = HYPERVISOR_dom0_op(&op);
> > > > > > > > > +    if (ret)
> > > > > > > > > +        return 0;
> > > > > > > > > +
> > > > > > > > > +    return op.u.pcpu_info.apic_id;

        return (op.u.pcpu_info.apic_id << 24);

indeed fixes the problem.

-boris


> > > > > > > > >    }
> > > > > > > > >
> > > > > > > > >    static void xen_apic_write(u32 reg, u32 val)
> > > I added debugging to all exit paths that could return 0 (which is what the
> > > boot_cpu_physical_apicid is set to with that patch. Which would only leave the
> > > case of the HV call returning the wrong value somehow...
> > Hmmm, so xen_apic_read is still correct...
> >
> > [    0.000000] ACPI: Local APIC address 0xfee00000
> > [    0.000000] xxx xen_apic_read(20)
> > [    0.000000] xxx xen_apic_read ->  10
> > [    0.000000] boot_cpu_physical_apicid = 0
> > [    0.000000] xxx xen_apic_read(30)
> > [    0.000000] +- apic version = 10
> >
> > there seems to be a slightly strange tweak (at least for me) in read_apic_id...
> >
> > static inline unsigned int read_apic_id(void)
> > {
> >          unsigned int reg;
> >
> >          reg = apic_read(APIC_ID); // calls apic->read(reg)
> >
> >          return apic->get_apic_id(reg);
> Duh!! Let me spin out a new patch that will do this.
> > }
>
>
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel


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