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From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: Yang Z Zhang <yang.z.zhang@intel.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	Kevin Tian <kevin.tian@intel.com>,
	Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>,
	Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH] x86/ats: Disable Address Translation Services by default
Date: Thu, 28 Aug 2014 05:07:12 -0500	[thread overview]
Message-ID: <53FEFF50.8040605@amd.com> (raw)
In-Reply-To: <53FF04A8020000780002E8D8@mail.emea.novell.com>



On 08/28/2014 03:30 AM, Jan Beulich wrote:
>>>> On 28.08.14 at 10:18, <suravee.suthikulpanit@amd.com> wrote:
>> On 08/28/2014 02:32 AM, Jan Beulich wrote:
>>>>>> On 28.08.14 at 09:08, <suravee.suthikulpanit@amd.com> 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@amd.com>

      reply	other threads:[~2014-08-28 10:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-20 16:01 [PATCH] x86/ats: Disable Address Translation Services by default Andrew Cooper
2014-08-22 12:39 ` Jan Beulich
2014-08-27  0:37   ` Zhang, Yang Z
2014-08-27  6:21     ` Jan Beulich
2014-08-28  7:08   ` Suravee Suthikulpanit
2014-08-28  7:32     ` Jan Beulich
2014-08-28  8:18       ` Suravee Suthikulpanit
2014-08-28  8:30         ` Jan Beulich
2014-08-28 10:07           ` Suravee Suthikulpanit [this message]

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