Re: [Xen-devel] [PATCH] x86/ats: Disable Address Translation Services by default

[Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>]

On 08/28/2014 03:30 AM, Jan Beulich wrote:
> > > > On 28.08.14 at 10:18, <suravee.suthikulpanit@xxxxxxx> wrote:
> > On 08/28/2014 02:32 AM, Jan Beulich wrote:
> > > > > > On 28.08.14 at 09:08, <suravee.suthikulpanit@xxxxxxx> wrote:
> > > > I have verified that PCI device pass-through works with ATS disabled.
> > > > Although, could you please help described how "asynchronous queued
> > > > invalidation support" supposed to work?
> > > Are asking about the abstract model, or the specific implementation?
> > > The former is quite obvious is think (utilize the respective interrupt to
> > > get notified of completions and suspend the execution in the current
> > > context until then),
> > So, what Andrew is saying is that the current implementation which uses
> > the "synchronous wait for completion" is not safe? May be I'm not
> > getting the whole picture here of how it is unsafe.
> It may be spinning for up to a second, and for ATS it would really
> need to be spinning for up to 60 seconds (perhaps even 90,
> depending on how to interpret the spec).
>
> Jan
Thanks for clarification.

Acked-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>

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