From: "Jan Beulich" <JBeulich@suse.com>
To: Tianyu Lan <tianyu.lan@intel.com>
Cc: "yang.zhang.wz@gmail.com" <yang.zhang.wz@gmail.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>,
Kevin Tian <kevin.tian@intel.com>,
Jun Nakajima <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, 25 Aug 2016 05:11:43 -0600 [thread overview]
Message-ID: <57BEEE8F0200007800108EEE@prv-mh.provo.novell.com> (raw)
In-Reply-To: <b17f9cc8-955d-c7e7-f944-a20a77f75d64@intel.com>
>>> On 17.08.16 at 14:05, <tianyu.lan@intel.com> wrote:
> 1 Motivation for Xen vIOMMU
> ============================================================================
> ===
> 1.1 Enable more than 255 vcpu support
> HPC virtualization requires more than 255 vcpus support in a single VM
> to meet parallel computing requirement. More than 255 vcpus support
> requires interrupt remapping capability present on vIOMMU to deliver
> interrupt to #vcpu >255 Otherwise Linux guest fails to boot up with >255
> vcpus if interrupt remapping is absent.
I continue to question this as a valid motivation at this point in
time, for the reasons Andrew has been explaining.
> 2. Xen vIOMMU Architecture
> ============================================================================
> ====
>
> * vIOMMU will be inside Xen hypervisor for following factors
> 1) Avoid round trips between Qemu and Xen hypervisor
> 2) Ease of integration with the rest of the hypervisor
> 3) HVMlite/PVH doesn't use Qemu
> * Dummy xen-vIOMMU in Qemu as a wrapper of new hypercall to create
> /destory vIOMMU in hypervisor and deal with virtual PCI device's 2th
> level translation.
How does the create/destroy part of this match up with 3) right
ahead of it?
> 3 Xen hypervisor
> ==========================================================================
>
> 3.1 New hypercall XEN_SYSCTL_viommu_op
> 1) Definition of "struct xen_sysctl_viommu_op" as new hypercall parameter.
>
> struct xen_sysctl_viommu_op {
> u32 cmd;
> u32 domid;
> union {
> struct {
> u32 capabilities;
> } query_capabilities;
> struct {
> u32 capabilities;
> u64 base_address;
> } create_iommu;
> struct {
> u8 bus;
> u8 devfn;
Please can we avoid introducing any new interfaces without segment/
domain value, even if for now it'll be always zero?
> u64 iova;
> u64 translated_addr;
> u64 addr_mask; /* Translation page size */
> IOMMUAccessFlags permisson;
> } 2th_level_translation;
I suppose "translated_addr" is an output here, but for the following
fields this already isn't clear. Please add IN and OUT annotations for
clarity.
Also, may I suggest to name this "l2_translation"? (But there are
other implementation specific things to be considered here, which
I guess don't belong into a design doc discussion.)
> };
>
> typedef enum {
> IOMMU_NONE = 0,
> IOMMU_RO = 1,
> IOMMU_WO = 2,
> IOMMU_RW = 3,
> } IOMMUAccessFlags;
>
>
> Definition of VIOMMU subops:
> #define XEN_SYSCTL_viommu_query_capability 0
> #define XEN_SYSCTL_viommu_create 1
> #define XEN_SYSCTL_viommu_destroy 2
> #define XEN_SYSCTL_viommu_dma_translation_for_vpdev 3
>
> Definition of VIOMMU capabilities
> #define XEN_VIOMMU_CAPABILITY_1nd_level_translation (1 << 0)
> #define XEN_VIOMMU_CAPABILITY_2nd_level_translation (1 << 1)
l1 and l2 respectively again, please.
> 3.3 Interrupt remapping
> Interrupts from virtual devices and physical devices will be delivered
> to vlapic from vIOAPIC and vMSI. It needs to add interrupt remapping
> hooks in the vmsi_deliver() and ioapic_deliver() to find target vlapic
> according interrupt remapping table. The following diagram shows the logic.
Missing diagram or stale sentence?
> 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?
Jan
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next prev parent reply other threads:[~2016-08-25 11:11 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 [this message]
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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