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RE: [Xen-ia64-devel] VTD is coming
>From: Akio Takebe [mailto:takebe_akio@xxxxxxxxxxxxxx]
>Sent: 2007年5月11日 10:54
>To: Xu, Anthony; Isaku Yamahata
>Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
>Subject: RE: [Xen-ia64-devel] VTD is coming
>
>Hi, Anthony
>
>I have a question.
>Do we need to set not only tables included dma page
>but also all page table to VTd?
We don't know which pages guest OS will use as dma page,
So we let vtd page table translate all physical address
belonging to guest.
>If yes, do we need to diable dma even when we chage any page table
>not related in dma-remapping?
we needn't and can't.
Vtd page table is maintained by xen.
When xen changes vtd page table, the changed entries should not
be used by DMA operation. What xen needs to do is to flush corresponding
IO-TLBs.
Do you find the scenarios where race conditions exist?
>
>Best Regards,
>
>Akio Takebe
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