Re: [Xen-devel] [PATCH v4 0/3] VT-d Device-TLB flush issue

["Jan Beulich" <jbeulich@xxxxxxxx>]

>>> Quan Xu <quan.xu@xxxxxxxxx> 12/23/15 9:26 AM >>>
>This patches are based on Kevin Tian's previous discussion 'Revisit VT-d 
>asynchronous flush issue'.
>Fix current timeout concern and also allow limited ATS support in a light way:
>
>1. Check VT-d Device-TLB flush error.
>This patch checks all kinds of error and all the way up the call trees of VT-d 
>Device-TLB flush.
>
>2. Reduce spin timeout to 1ms, which can be boot-time changed with 
>'iommu_qi_timeout_ms'.
>For example:
>multiboot /boot/xen.gz ats=1 iommu_qi_timeout_ms=100
>
>3. Fix vt-d Device-TLB flush timeout issue.
>Now if IOTLB/Context/IETC flush is timeout, panic hypervisor. The coming patch
>set will fix it.

There must have been a misunderstanding: Your earlier outline didn't indicate 
you
mean to introduce panics here, even if only temporarily. I'm afraid I'm not 
currently
willing to take any conceptually wrong patches anymore with just the promise of
fixing the issue(s) later (and I think we've mentioned this in some past 
discussion
on the list, albeit unlikely in the context of any of your work). This may mean 
that
the earlier described ordering of things you mean to do needs changing.

I'm sorry that you're hit first by this, the more that it was not you but 
colleagues of
yours causing this change to the acceptance model.

Jan


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