Re: [Xen-ia64-devel] [PATCH] Fix some IPF Xen VT-d bugs

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

On Mon, Jan 05, 2009 at 05:39:52PM +0800, Cui, Dexuan wrote:
> Isaku Yamahata wrote:
> > On x86 case p2m_lock/unlock() avoids the race, but ia64 doesn't have
> > such lock.
> > At this moment, the only HVM domain would be supported.
> OK, I understand we can't support pv iommu before resolving the lockless p2m 
> issue.
> 
> > The issue is dom0 case. I suppose it can be supported by mapping
> > all the pages except xen pages at boot time and not iommu
> > mapping/unmapping because those pages are already mapped to dom0
> > by intel_iommu_domain_init().
> I think actually we do this.
> For the special pv guest Dom0, I think there is no issue here because
>  dom0->need_iommu is actually always 0 (when Dom0 boots up and xen assigns 
> all the devices to Dom0, xen doesn't invoke assign_device(), and invoking 
> iommu_domain_init()/intel_iommu_domain_init() doesn't cause need_iommu(dom0) 
> to be 1).

Okay, I missed that.
-- 
yamahata

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