Re: [Xen-devel] [PATCH v2 10/11] pvh: Send an SCI on VCPU hotplug event

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 11/15/2016 04:36 AM, Jan Beulich wrote:
>>>> On 09.11.16 at 15:39, <boris.ostrovsky@xxxxxxxxxx> wrote:
>> --- a/xen/arch/x86/domctl.c
>> +++ b/xen/arch/x86/domctl.c
>> @@ -1443,6 +1443,18 @@ long arch_do_domctl(
>>              break;
>>  
>>          d->arch.avail_vcpus = num;
>> +
>> +        /*
>> +         * For PVH guests we need to send an SCI and set enable/status
>> +         * bits in GPE block (DSDT specifies _E02, so it's bit 2).
>> +         */
>> +        if ( is_hvm_domain(d) && !has_ioreq_cpuhp(d) )
>> +        {
>> +            d->arch.hvm_domain.acpi_io.gpe[2] =
>> +                d->arch.hvm_domain.acpi_io.gpe[0] = 4;
>> +            send_guest_vcpu_virq(d->vcpu[0], VIRQ_SCI);
>> +        }
> The use of d->vcpu[0] here supports this not being a per-vCPU
> vIRQ. And it has two problems: you don't check it to be non-NULL
> (see send_guest_global_virq(), which you want to make
> non-static), and what do you do if vCPU0 is offline (i.e. you also
> want to generalize send_guest_global_virq())?

IIRC in Linux you can't offline BP but I guess in general it should be
supported.

-boris

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