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From: David Gibson <david@gibson.dropbear.id.au>
To: "Liu, Yi L" <yi.l.liu@intel.com>
Cc: Peter Xu <peterx@redhat.com>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"mst@redhat.com" <mst@redhat.com>,
	"eric.auger@redhat.com" <eric.auger@redhat.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	"Tian, Jun J" <jun.j.tian@intel.com>,
	"Sun, Yi Y" <yi.y.sun@intel.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"Wu, Hao" <hao.wu@intel.com>,
	Jacob Pan <jacob.jun.pan@linux.intel.com>,
	Yi Sun <yi.y.sun@linux.intel.com>
Subject: Re: [RFC v3 03/25] hw/iommu: introduce IOMMUContext
Date: Fri, 14 Feb 2020 16:36:20 +1100	[thread overview]
Message-ID: <20200214053620.GR124369@umbus.fritz.box> (raw)
In-Reply-To: <A2975661238FB949B60364EF0F2C25743A1BA4D8@SHSMSX104.ccr.corp.intel.com>

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On Wed, Feb 12, 2020 at 07:15:13AM +0000, Liu, Yi L wrote:
> Hi Peter,
> 
> > From: Peter Xu <peterx@redhat.com>
> > Sent: Wednesday, February 12, 2020 12:59 AM
> > To: Liu, Yi L <yi.l.liu@intel.com>
> > Subject: Re: [RFC v3 03/25] hw/iommu: introduce IOMMUContext
> > 
> > On Fri, Jan 31, 2020 at 11:42:13AM +0000, Liu, Yi L wrote:
> > > > I'm not very clear on the relationship betwen an IOMMUContext and a
> > > > DualStageIOMMUObject.  Can there be many IOMMUContexts to a
> > > > DualStageIOMMUOBject?  The other way around?  Or is it just
> > > > zero-or-one DualStageIOMMUObjects to an IOMMUContext?
> > >
> > > It is possible. As the below patch shows, DualStageIOMMUObject is per vfio
> > > container. IOMMUContext can be either per-device or shared across devices,
> > > it depends on vendor specific vIOMMU emulators.
> > 
> > Is there an example when an IOMMUContext can be not per-device?
> 
> No, I don’t have such example so far. But as IOMMUContext is got from
> pci_device_iommu_context(),  in concept it possible to be not per-device.
> It is kind of leave to vIOMMU to decide if different devices could share a
> single IOMMUContext.

On the "pseries" machine the vIOMMU only has one set of translations
for a whole virtual PCI Host Bridge (vPHB).  So if you attach multiple
devices to a single vPHB, I believe you'd get multiple devices in an
IOMMUContext.  Well.. if we did the PASID stuff, which we don't at the
moment.

Note that on pseries on the other hand it's routine to create multiple
vPHBs, rather than multiple PCI roots being an oddity as it is on x86.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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  parent reply	other threads:[~2020-02-14  5:36 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-29 12:16 [RFC v3 00/25] intel_iommu: expose Shared Virtual Addressing to VMs Liu, Yi L
2020-01-29 12:16 ` [RFC v3 01/25] hw/pci: modify pci_setup_iommu() to set PCIIOMMUOps Liu, Yi L
2020-01-29 12:16 ` [RFC v3 02/25] hw/iommu: introduce DualStageIOMMUObject Liu, Yi L
2020-01-31  3:59   ` David Gibson
2020-01-31 11:42     ` Liu, Yi L
2020-02-12  6:32       ` David Gibson
2020-01-29 12:16 ` [RFC v3 03/25] hw/iommu: introduce IOMMUContext Liu, Yi L
2020-01-31  4:06   ` David Gibson
2020-01-31 11:42     ` Liu, Yi L
2020-02-11 16:58       ` Peter Xu
2020-02-12  7:15         ` Liu, Yi L
2020-02-12 15:59           ` Peter Xu
2020-02-13  2:46             ` Liu, Yi L
2020-02-14  5:36           ` David Gibson [this message]
2020-02-15  6:25             ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 04/25] hw/pci: introduce pci_device_iommu_context() Liu, Yi L
2020-01-29 12:16 ` [RFC v3 05/25] intel_iommu: provide get_iommu_context() callback Liu, Yi L
2020-01-29 12:16 ` [RFC v3 06/25] scripts/update-linux-headers: Import iommu.h Liu, Yi L
2020-01-29 12:25   ` Cornelia Huck
2020-01-31 11:40     ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 07/25] header file update VFIO/IOMMU vSVA APIs Liu, Yi L
2020-01-29 12:28   ` Cornelia Huck
2020-01-31 11:41     ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 08/25] vfio: pass IOMMUContext into vfio_get_group() Liu, Yi L
2020-01-29 12:16 ` [RFC v3 09/25] vfio: check VFIO_TYPE1_NESTING_IOMMU support Liu, Yi L
2020-02-11 19:08   ` Peter Xu
2020-02-12  7:16     ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 10/25] vfio: register DualStageIOMMUObject to vIOMMU Liu, Yi L
2020-01-29 12:16 ` [RFC v3 11/25] vfio: get stage-1 pasid formats from Kernel Liu, Yi L
2020-02-11 19:30   ` Peter Xu
2020-02-12  7:19     ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 12/25] vfio/common: add pasid_alloc/free support Liu, Yi L
2020-02-11 19:31   ` Peter Xu
2020-02-12  7:20     ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 13/25] intel_iommu: modify x-scalable-mode to be string option Liu, Yi L
2020-02-11 19:43   ` Peter Xu
2020-02-12  7:28     ` Liu, Yi L
2020-02-12 16:05       ` Peter Xu
2020-02-13  2:44         ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 14/25] intel_iommu: add virtual command capability support Liu, Yi L
2020-02-11 20:16   ` Peter Xu
2020-02-12  7:32     ` Liu, Yi L
2020-02-11 21:56   ` Peter Xu
2020-02-13  2:40     ` Liu, Yi L
2020-02-13 14:31       ` Peter Xu
2020-02-13 15:08         ` Peter Xu
2020-02-15  8:49           ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 15/25] intel_iommu: process pasid cache invalidation Liu, Yi L
2020-02-11 20:17   ` Peter Xu
2020-02-12  7:33     ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 16/25] intel_iommu: add PASID cache management infrastructure Liu, Yi L
2020-02-11 23:35   ` Peter Xu
2020-02-12  8:37     ` Liu, Yi L
2020-02-12 15:26       ` Peter Xu
2020-02-13  2:59         ` Liu, Yi L
2020-02-13 15:14           ` Peter Xu
2020-02-15  8:50             ` Liu, Yi L
2020-01-29 12:16 ` [RFC v3 17/25] vfio: add bind stage-1 page table support Liu, Yi L
2020-01-29 12:16 ` [RFC v3 18/25] intel_iommu: bind/unbind guest page table to host Liu, Yi L
2020-01-29 12:16 ` [RFC v3 19/25] intel_iommu: replay guest pasid bindings " Liu, Yi L
2020-01-29 12:16 ` [RFC v3 20/25] intel_iommu: replay pasid binds after context cache invalidation Liu, Yi L
2020-01-29 12:16 ` [RFC v3 21/25] intel_iommu: do not pass down pasid bind for PASID #0 Liu, Yi L
2020-01-29 12:16 ` [RFC v3 22/25] vfio: add support for flush iommu stage-1 cache Liu, Yi L
2020-01-29 12:16 ` [RFC v3 23/25] intel_iommu: process PASID-based iotlb invalidation Liu, Yi L
2020-01-29 12:16 ` [RFC v3 24/25] intel_iommu: propagate PASID-based iotlb invalidation to host Liu, Yi L
2020-01-29 12:16 ` [RFC v3 25/25] intel_iommu: process PASID-based Device-TLB invalidation Liu, Yi L
2020-01-29 13:44 ` [RFC v3 00/25] intel_iommu: expose Shared Virtual Addressing to VMs no-reply
2020-01-29 13:48 ` no-reply

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