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From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jan Beulich <JBeulich@suse.com>, "Lan, Tianyu" <tianyu.lan@intel.com>
Cc: "yang.zhang.wz@gmail.com" <yang.zhang.wz@gmail.com>,
	"xuquan8@huawei.com" <xuquan8@huawei.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	"ian.jackson@eu.citrix.com" <ian.jackson@eu.citrix.com>,
	"Nakajima, Jun" <jun.nakajima@intel.com>,
	"anthony.perard@citrix.com" <anthony.perard@citrix.com>,
	xen-devel <xen-devel@lists.xenproject.org>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: Xen virtual IOMMU high level design doc
Date: Thu, 1 Sep 2016 01:26:26 +0000	[thread overview]
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D18DEBEE3A@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <57C6E378020000780010A756@prv-mh.provo.novell.com>

> From: Jan Beulich [mailto:JBeulich@suse.com]
> Sent: Wednesday, August 31, 2016 8:03 PM
> >>> 3.5 Implementation consideration
> >>> Linux Intel IOMMU driver will fail to be loaded without 2th level
> >>> translation support even if interrupt remapping and 1th level
> >>> translation are available. This means it's needed to enable 2th level
> >>> translation first before other functions.
> >>
> >> Is there a reason for this? I.e. do they unconditionally need that
> >> functionality?
> >
> > Yes, Linux intel IOMMU driver unconditionally needs l2 translation.
> > Driver checks whether there is a valid sagaw(supported Adjusted Guest
> > Address Widths) during initializing IOMMU data struct and return error
> > if not.
> 
> How about my first question then?
> 
> Jan

VT-d spec doesn't define a capability bit for the 2nd level translation 
(for 1st level or intr remapping, there do have such capability bit to
report). So architecturally there is no way to tell guest that 2nd level 
translation capability is not available, so existing Linux behavior is.... 
just correct.

Thanks
Kevin
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  reply	other threads:[~2016-09-01  1:26 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-26  8:29 Discussion about virtual iommu support for Xen guest Lan Tianyu
2016-05-26  8:42 ` Dong, Eddie
2016-05-27  2:26   ` Lan Tianyu
2016-05-27  8:11     ` Tian, Kevin
2016-05-26 11:35 ` Andrew Cooper
2016-05-27  8:19   ` Lan Tianyu
2016-06-02 15:03     ` Lan, Tianyu
2016-06-02 18:58       ` Andrew Cooper
2016-06-03 11:01         ` Current PVH/HVMlite work and planning (was :Re: Discussion about virtual iommu support for Xen guest) Roger Pau Monne
2016-06-03 11:21           ` Tian, Kevin
2016-06-03 11:52             ` Roger Pau Monne
2016-06-03 12:11               ` Tian, Kevin
2016-06-03 16:56                 ` Stefano Stabellini
2016-06-07  5:48                   ` Tian, Kevin
2016-06-03 11:17         ` Discussion about virtual iommu support for Xen guest Tian, Kevin
2016-06-03 13:09           ` Lan, Tianyu
2016-06-03 14:00             ` Andrew Cooper
2016-06-03 13:51           ` Andrew Cooper
2016-06-03 14:31             ` Jan Beulich
2016-06-03 17:14             ` Stefano Stabellini
2016-06-07  5:14               ` Tian, Kevin
2016-06-07  7:26                 ` Jan Beulich
2016-06-07 10:07                 ` Stefano Stabellini
2016-06-08  8:11                   ` Tian, Kevin
2016-06-26 13:42                     ` Lan, Tianyu
2016-06-29  3:04                       ` Tian, Kevin
2016-07-05 13:37                         ` Lan, Tianyu
2016-07-05 13:57                           ` Jan Beulich
2016-07-05 14:19                             ` Lan, Tianyu
2016-08-17 12:05                             ` Xen virtual IOMMU high level design doc Lan, Tianyu
2016-08-17 12:42                               ` Paul Durrant
2016-08-18  2:57                                 ` Lan, Tianyu
2016-08-25 11:11                               ` Jan Beulich
2016-08-31  8:39                                 ` Lan Tianyu
2016-08-31 12:02                                   ` Jan Beulich
2016-09-01  1:26                                     ` Tian, Kevin [this message]
2016-09-01  2:35                                     ` Lan Tianyu
2016-09-15 14:22                               ` Lan, Tianyu
2016-10-05 18:36                                 ` Konrad Rzeszutek Wilk
2016-10-11  1:52                                   ` Lan Tianyu
2016-11-23 18:19                               ` Edgar E. Iglesias
2016-11-23 19:09                                 ` Stefano Stabellini
2016-11-24  2:00                                   ` Tian, Kevin
2016-11-24  4:09                                     ` Edgar E. Iglesias
2016-11-24  6:49                                       ` Lan Tianyu
2016-11-24 13:37                                         ` Edgar E. Iglesias
2016-11-25  2:01                                           ` Xuquan (Quan Xu)
2016-11-25  5:53                                           ` Lan, Tianyu
2016-10-18 14:14                             ` Xen virtual IOMMU high level design doc V2 Lan Tianyu
2016-10-18 19:17                               ` Andrew Cooper
2016-10-20  9:53                                 ` Tian, Kevin
2016-10-20 18:10                                   ` Andrew Cooper
2016-10-20 14:17                                 ` Lan Tianyu
2016-10-20 20:36                                   ` Andrew Cooper
2016-10-22  7:32                                     ` Lan, Tianyu
2016-10-26  9:39                                       ` Jan Beulich
2016-10-26 15:03                                         ` Lan, Tianyu
2016-11-03 15:41                                         ` Lan, Tianyu
2016-10-28 15:36                                     ` Lan Tianyu
2016-10-18 20:26                               ` Konrad Rzeszutek Wilk
2016-10-20 10:11                                 ` Tian, Kevin
2016-10-20 14:56                                 ` Lan, Tianyu
2016-10-26  9:36                               ` Jan Beulich
2016-10-26 14:53                                 ` Lan, Tianyu
2016-11-17 15:36                             ` Xen virtual IOMMU high level design doc V3 Lan Tianyu
2016-11-18 19:43                               ` Julien Grall
2016-11-21  2:21                                 ` Lan, Tianyu
2016-11-21 13:17                                   ` Julien Grall
2016-11-21 18:24                                     ` Stefano Stabellini
2016-11-21  7:05                               ` Tian, Kevin
2016-11-23  1:36                                 ` Lan Tianyu
2016-11-21 13:41                               ` Andrew Cooper
2016-11-22  6:02                                 ` Tian, Kevin
2016-11-22  8:32                                 ` Lan Tianyu
2016-11-22 10:24                               ` Jan Beulich
2016-11-24  2:34                                 ` Lan Tianyu
2016-06-03 19:51             ` Is: 'basic pci bridge and root device support. 'Was:Re: Discussion about virtual iommu support for Xen guest Konrad Rzeszutek Wilk
2016-06-06  9:55               ` Jan Beulich
2016-06-06 17:25                 ` Konrad Rzeszutek Wilk
2016-08-02 15:15     ` Lan, Tianyu
2016-05-27  8:35   ` Tian, Kevin
2016-05-27  8:46     ` Paul Durrant
2016-05-27  9:39       ` Tian, Kevin
2016-05-31  9:43   ` George Dunlap
2016-05-27  2:26 ` Yang Zhang
2016-05-27  8:13   ` Tian, Kevin

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