From mboxrd@z Thu Jan  1 00:00:00 1970
From: Anthony Liguori <anthony@codemonkey.ws>
Subject: Re: [PATCH] KVM: PCIPT: VT-d: fix guest unmap
Date: Fri, 20 Jun 2008 14:28:27 -0500
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To: Avi Kivity <avi@qumranet.com>
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Avi Kivity wrote:
> Anthony Liguori wrote:
>> I think the current VT-d code needs some reworking.
>>
>> We should build the table as the shadow page table gets built.  We 
>> should suppress iotlb flushes unless the table is actually being 
>> updated.
>>
>
> We can't, since we need the iommu tables populated before we issue any 
> dma.

Yes, as I've mentioned, the lack of a DMA window notification API can be 
handled as a special case.

> Perhaps we want something like MAP_POPULATE for shadow, which would 
> then affect the iommu tables.  Userspace would then do:
>
> mlock()
> ... set up device assignment
> ioctl(..., KVM_POPULATE)

Exactly like this :-)

Regards,

Anthony Liguori