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From: "Liu, Yi L" <yi.l.liu@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Wang <jasowang@redhat.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"eric.auger@redhat.com" <eric.auger@redhat.com>,
	"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
	"joro@8bytes.org" <joro@8bytes.org>,
	"jacob.jun.pan@linux.intel.com" <jacob.jun.pan@linux.intel.com>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	"Tian, Jun J" <jun.j.tian@intel.com>,
	"Sun, Yi Y" <yi.y.sun@intel.com>,
	"jean-philippe@linaro.org" <jean-philippe@linaro.org>,
	"peterx@redhat.com" <peterx@redhat.com>,
	"Wu, Hao" <hao.wu@intel.com>,
	"stefanha@gmail.com" <stefanha@gmail.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"Michael S. Tsirkin" <mst@redhat.com>
Subject: RE: (proposal) RE: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs
Date: Tue, 20 Oct 2020 14:09:44 +0000	[thread overview]
Message-ID: <DM5PR11MB1435D4CBA2817FA2C5F92539C31F0@DM5PR11MB1435.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20201020140504.GJ6219@nvidia.com>

> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Tuesday, October 20, 2020 10:05 PM
> To: Liu, Yi L <yi.l.liu@intel.com>
> 
> On Tue, Oct 20, 2020 at 02:00:31PM +0000, Liu, Yi L wrote:
> > > From: Jason Gunthorpe <jgg@nvidia.com>
> > > Sent: Tuesday, October 20, 2020 9:55 PM
> > >
> > > On Tue, Oct 20, 2020 at 09:40:14AM +0000, Liu, Yi L wrote:
> > >
> > > > > See previous discussion with Kevin. If I understand correctly,
> > > > > you expect a
> > > shared
> > > > > L2 table if vDPA and VFIO device are using the same PASID.
> > > >
> > > > L2 table sharing is not mandatory. The mapping is the same, but no
> > > > need to assume L2 tables are shared. Especially for VFIO/vDPA
> > > > devices. Even within a passthru framework, like VFIO, if the
> > > > attributes of backend IOMMU are not the same, the L2 page table are not
> shared, but the mapping is the same.
> > >
> > > I think not being able to share the PASID shows exactly why this
> > > VFIO centric approach is bad.
> >
> > no, I didn't say PASID is not sharable. My point is sharing L2 page
> > table is not mandatory.
> 
> IMHO a PASID should be 1:1 with a page table, what does it even mean to share
> a PASID but have different page tables?

PASID is actually 1:1 with an address space. Not really needs to be 1:1 with
page table. :-)

Regards,
Yi Liu

> Jason

  reply	other threads:[~2020-10-20 14:09 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-12  8:38 (proposal) RE: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs Tian, Kevin
2020-10-13  6:22 ` Jason Wang
2020-10-14  3:08   ` Tian, Kevin
2020-10-14 23:10     ` Alex Williamson
2020-10-15  7:02       ` Jason Wang
2020-10-15  6:52     ` Jason Wang
2020-10-15  7:58       ` Tian, Kevin
2020-10-15  8:40         ` Jason Wang
2020-10-15 10:14           ` Liu, Yi L
2020-10-20  6:18             ` Jason Wang
2020-10-20  8:19               ` Liu, Yi L
2020-10-20  9:19                 ` Jason Wang
2020-10-20  9:40                   ` Liu, Yi L
2020-10-20 13:54                     ` Jason Gunthorpe
2020-10-20 14:00                       ` Liu, Yi L
2020-10-20 14:05                         ` Jason Gunthorpe
2020-10-20 14:09                           ` Liu, Yi L [this message]
2020-10-13 10:27 ` Jean-Philippe Brucker
2020-10-14  2:11   ` Tian, Kevin
2020-10-14  3:16 ` Tian, Kevin
2020-10-16 15:36   ` Jason Gunthorpe
2020-10-19  8:39     ` Liu, Yi L
2020-10-19 14:25       ` Jason Gunthorpe
2020-10-20 10:21         ` Liu, Yi L
2020-10-20 14:02           ` Jason Gunthorpe
2020-10-20 14:19             ` Liu, Yi L
2020-10-21  2:21               ` Jason Wang
2020-10-20 16:24             ` Raj, Ashok
2020-10-20 17:03               ` Jason Gunthorpe
2020-10-20 19:51                 ` Raj, Ashok
2020-10-20 19:55                   ` Jason Gunthorpe
2020-10-20 20:08                     ` Raj, Ashok
2020-10-20 20:14                       ` Jason Gunthorpe
2020-10-20 20:27                         ` Raj, Ashok
2020-10-21 11:48                           ` Jason Gunthorpe
2020-10-21 17:51                             ` Raj, Ashok
2020-10-21 18:24                               ` Jason Gunthorpe
2020-10-21 20:03                                 ` Raj, Ashok
2020-10-21 23:32                                   ` Jason Gunthorpe
2020-10-21 23:53                                     ` Raj, Ashok
2020-10-22  2:55                               ` Jason Wang
2020-10-22  3:54                                 ` Liu, Yi L
2020-10-22  4:38                                   ` Jason Wang
2020-11-03  9:52 ` joro
2020-11-03 12:56   ` Jason Gunthorpe
2020-11-03 13:18     ` joro
2020-11-03 13:23       ` Jason Gunthorpe
2020-11-03 14:03         ` joro
2020-11-03 14:06           ` Jason Gunthorpe
2020-11-03 14:35             ` joro
2020-11-03 15:22               ` Jason Gunthorpe
2020-11-03 16:55                 ` joro
2020-11-03 17:48                   ` Jason Gunthorpe
2020-11-03 19:14                     ` joro
2020-11-04 19:29                       ` Jason Gunthorpe

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