Re: [PATCH v5 2/2] x86/xen: Allow per-domain usage of hardware virtualized APIC

[Jan Beulich <jbeulich@xxxxxxxx>]

On 08.03.2022 12:38, Roger Pau Monné wrote:
> On Mon, Mar 07, 2022 at 03:06:09PM +0000, Jane Malalane wrote:
>> @@ -685,13 +687,31 @@ int arch_sanitise_domain_config(struct 
>> xen_domctl_createdomain *config)
>>          }
>>      }
>>  
>> -    if ( config->arch.misc_flags & ~XEN_X86_MSR_RELAXED )
>> +    if ( config->arch.misc_flags & ~(XEN_X86_MSR_RELAXED |
>> +                                     XEN_X86_ASSISTED_XAPIC |
>> +                                     XEN_X86_ASSISTED_X2APIC) )
>>      {
>>          dprintk(XENLOG_INFO, "Invalid arch misc flags %#x\n",
>>                  config->arch.misc_flags);
>>          return -EINVAL;
>>      }
>>  
>> +    if ( (assisted_xapic || assisted_x2apic) && !hvm )
>> +    {
>> +        dprintk(XENLOG_INFO,
>> +                "Interrupt Controller Virtualization not supported for 
>> PV\n");
>> +        return -EINVAL;
>> +    }
>> +
>> +    if ( (assisted_xapic && !assisted_xapic_available) ||
>> +         (assisted_x2apic && !assisted_x2apic_available) )
>> +    {
>> +        dprintk(XENLOG_INFO,
>> +                "Hardware assisted x%sAPIC requested but not available\n",
>> +                assisted_xapic && !assisted_xapic_available ? "" : "2");
>> +        return -EINVAL;
> 
> I think for those two you could return -ENODEV if others agree.

If by "two" you mean the xAPIC and x2APIC aspects here (and not e.g. this
and the earlier if()), then I agree. I'm always in favor of using distinct
error codes when possible and at least halfway sensible.

Jan