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* Discussion about virtual iommu support for Xen guest
@ 2016-05-26  8:29 Lan Tianyu
  2016-05-26  8:42 ` Dong, Eddie
                   ` (2 more replies)
  0 siblings, 3 replies; 86+ messages in thread
From: Lan Tianyu @ 2016-05-26  8:29 UTC (permalink / raw)
  To: jbeulich, sstabellini, ian.jackson, xen-devel, kevin.tian, Dong,
	Eddie, Nakajima, Jun, yang.zhang.wz, anthony.perard

Hi All:
We try pushing virtual iommu support for Xen guest and there are some
features blocked by it.

Motivation:
-----------------------
1) Add SVM(Shared Virtual Memory) support for Xen guest
To support iGFX pass-through for SVM enabled devices, it requires
virtual iommu support to emulate related registers and intercept/handle
guest SVM configure in the VMM.

2) Increase max vcpu support for one VM.

So far, max vcpu for Xen hvm guest is 128. For HPC(High Performance
Computing) cloud computing, it requires more vcpus support in a single
VM. The usage model is to create just one VM on a machine with the
same number vcpus as logical cpus on the host and pin vcpu on each
logical cpu in order to get good compute performance.

Intel Xeon phi KNL(Knights Landing) is dedicated to HPC market and
supports 288 logical cpus. So we hope VM can support 288 vcpu
to meet HPC requirement.

Current Linux kernel requires IR(interrupt remapping) when MAX APIC
ID is > 255 because interrupt only can be delivered among 0~255 cpus
without IR. IR in VM relies on the virtual iommu support.

KVM Virtual iommu support status
------------------------
Current, Qemu has a basic virtual iommu to do address translation for
virtual device and it only works for the Q35 machine type. KVM reuses it
and Redhat is adding IR to support more than 255 vcpus.

How to add virtual iommu for Xen?
-------------------------
First idea came to my mind is to reuse Qemu virtual iommu but Xen didn't
support Q35 so far. Enabling Q35 for Xen seems not a short term task.
Anthony did some related jobs before.

I'd like to see your comments about how to implement virtual iommu for Xen.

1) Reuse Qemu virtual iommu or write a separate one for Xen?
2) Enable Q35 for Xen to reuse Qemu virtual iommu?

Your comments are very appreciated. Thanks a lot.
-- 
Best regards
Tianyu Lan

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^ permalink raw reply	[flat|nested] 86+ messages in thread

end of thread, other threads:[~2016-11-25  5:53 UTC | newest]

Thread overview: 86+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
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
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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