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SubjectRe: [Patch Part3 V5 5/8] iommu/vt-d: Enhance intel_irq_remapping driver to support DMAR unit hotplug
On 2014/9/16 15:00, Jiang Liu wrote:
> On 2014/9/15 10:20, Yijing Wang wrote:
>>> +static void ir_remove_ioapic_hpet_scope(struct intel_iommu *iommu)
>>> +{
>>> + int i;
>>>
>>> - ir_parse_one_hpet_scope(scope, iommu);
>>> - }
>>> - start += scope->length;
>>> - }
>>> + for (i = 0; i < MAX_HPET_TBS; i++)
>>> + if (ir_hpet[i].iommu == iommu)
>>> + ir_hpet[i].iommu = NULL;
>>
>> Hi Gerry, why not reset whole ir_hpe and ir_ioapic data struct?
> Hi Yijing,
> Thanks for review. Zero is legal for id, bus and devfn in
> struct ioapic_scope and struct hpet_scope. So we use domain field
> as a flag to mark entry valid or invalid and only reset iommu field.

Hi Gerry, use iommu field as a flag to mark entry valid may be not safe enough,
I found map_hpet_to_ir() and map_ioapic_to_ir() still only check the id field to return the valid iommu.

What about this case:
E.g. ir_hpet[2].id = N, ir_hpet[2].iommu = NULL, ir_hpet[4].id = N, ir_hpet[4].iommu = iommu;

ir_hpet[2] maybe released yet, and the hpet now has been saved in ir_hpet[4], but map_hpet_to_irq()
will return the wrong iommu(NULL).


static struct intel_iommu *map_hpet_to_ir(u8 hpet_id)
{
int i;

for (i = 0; i < MAX_HPET_TBS; i++)
if (ir_hpet[i].id == hpet_id)
return ir_hpet[i].iommu;
return NULL;
}

>
> Regards!
> Gerry
>>
>>
>>
>>>
>>> - return 0;
>>> + for (i = 0; i < MAX_IO_APICS; i++)
>>> + if (ir_ioapic[i].iommu == iommu)
>>> + ir_ioapic[i].iommu = NULL;
>>> }
>>>
>>
>> --
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>>
>
> .
>


--
Thanks!
Yijing



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