From: Jason Gunthorpe <jgg@nvidia.com>
To: "Liu, Yi L" <yi.l.liu@intel.com>
Cc: "Tian, Jun J" <jun.j.tian@intel.com>,
"Tian, Kevin" <kevin.tian@intel.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"jean-philippe@linaro.org" <jean-philippe@linaro.org>,
"stefanha@gmail.com" <stefanha@gmail.com>,
Jason Wang <jasowang@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Sun, Yi Y" <yi.y.sun@intel.com>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>, "Wu, Hao" <hao.wu@intel.com>
Subject: Re: (proposal) RE: [PATCH v7 00/16] vfio: expose virtual Shared Virtual Addressing to VMs
Date: Tue, 20 Oct 2020 11:05:04 -0300 [thread overview]
Message-ID: <20201020140504.GJ6219@nvidia.com> (raw)
In-Reply-To: <DM5PR11MB143591B85490D675F0628890C31F0@DM5PR11MB1435.namprd11.prod.outlook.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?
Jason
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next prev parent reply other threads:[~2020-10-20 14:05 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 [this message]
2020-10-20 14:09 ` Liu, Yi L
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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