From: "Dong, Eddie" <eddie.dong@intel.com>
To: "Lan, Tianyu" <tianyu.lan@intel.com>,
"jbeulich@suse.com" <jbeulich@suse.com>,
"sstabellini@kernel.org" <sstabellini@kernel.org>,
"ian.jackson@eu.citrix.com" <ian.jackson@eu.citrix.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"Nakajima, Jun" <jun.nakajima@intel.com>,
"yang.zhang.wz@gmail.com" <yang.zhang.wz@gmail.com>,
"anthony.perard@citrix.com" <anthony.perard@citrix.com>
Subject: Re: Discussion about virtual iommu support for Xen guest
Date: Thu, 26 May 2016 08:42:15 +0000 [thread overview]
Message-ID: <A12AC9D104E08D47BAF23C492F83C53B25EB1838@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <5746B3FA.6020401@intel.com>
If enabling virtual Q35 solves the problem, it has the advantage: When more and more virtual IOMMU feature comes (likely), we can reuse the KVM code for Xen.
How big is the effort for virtual Q35?
Thx Eddie
> -----Original Message-----
> From: Lan, Tianyu
> Sent: Thursday, May 26, 2016 4:30 PM
> To: jbeulich@suse.com; sstabellini@kernel.org; ian.jackson@eu.citrix.com;
> xen-devel@lists.xensource.com; Tian, Kevin <kevin.tian@intel.com>; Dong,
> Eddie <eddie.dong@intel.com>; Nakajima, Jun <jun.nakajima@intel.com>;
> yang.zhang.wz@gmail.com; anthony.perard@citrix.com
> Subject: Discussion about virtual iommu support for Xen guest
>
> 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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next prev parent reply other threads:[~2016-05-26 8:42 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 [this message]
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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