From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Wang <jasowang@redhat.com>,
Shahaf Shuler <shahafs@mellanox.com>,
Tiwei Bie <tiwei.bie@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"rob.miller@broadcom.com" <rob.miller@broadcom.com>,
"haotian.wang@sifive.com" <haotian.wang@sifive.com>,
"eperezma@redhat.com" <eperezma@redhat.com>,
"lulu@redhat.com" <lulu@redhat.com>,
Parav Pandit <parav@mellanox.com>,
"rdunlap@infradead.org" <rdunlap@infradead.org>,
"hch@infradead.org" <hch@infradead.org>,
Jiri Pirko <jiri@mellanox.com>,
"hanand@xilinx.com" <hanand@xilinx.com>, mhabets@solarflare.
Subject: Re: [PATCH] vhost: introduce vDPA based backend
Date: Wed, 5 Feb 2020 08:14:46 -0500 [thread overview]
Message-ID: <20200205081210-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20200205125648.GV23346@mellanox.com>
On Wed, Feb 05, 2020 at 08:56:48AM -0400, Jason Gunthorpe wrote:
> On Wed, Feb 05, 2020 at 03:50:14PM +0800, Jason Wang wrote:
> > > Would it be better for the map/umnap logic to happen inside each device ?
> > > Devices that needs the IOMMU will call iommu APIs from inside the driver callback.
> >
> > Technically, this can work. But if it can be done by vhost-vpda it will make
> > the vDPA driver more compact and easier to be implemented.
>
> Generally speaking, in the kernel, it is normal to not hoist code of
> out drivers into subsystems until 2-3 drivers are duplicating that
> code. It helps ensure the right design is used
>
> Jason
That's up to the sybsystem maintainer really, as there's also some
intuition involved in guessing a specific API is widely useful.
In-kernel APIs are flexible, if we find something isn't needed we just
drop it.
--
MST
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Wang <jasowang@redhat.com>,
Shahaf Shuler <shahafs@mellanox.com>,
Tiwei Bie <tiwei.bie@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"rob.miller@broadcom.com" <rob.miller@broadcom.com>,
"haotian.wang@sifive.com" <haotian.wang@sifive.com>,
"eperezma@redhat.com" <eperezma@redhat.com>,
"lulu@redhat.com" <lulu@redhat.com>,
Parav Pandit <parav@mellanox.com>,
"rdunlap@infradead.org" <rdunlap@infradead.org>,
"hch@infradead.org" <hch@infradead.org>,
Jiri Pirko <jiri@mellanox.com>,
"hanand@xilinx.com" <hanand@xilinx.com>,
"mhabets@solarflare.com" <mhabets@solarflare.com>,
"maxime.coquelin@redhat.com" <maxime.coquelin@redhat.com>,
"lingshan.zhu@intel.com" <lingshan.zhu@intel.com>,
"dan.daly@intel.com" <dan.daly@intel.com>,
"cunming.liang@intel.com" <cunming.liang@intel.com>,
"zhihong.wang@intel.com" <zhihong.wang@intel.com>
Subject: Re: [PATCH] vhost: introduce vDPA based backend
Date: Wed, 5 Feb 2020 08:14:46 -0500 [thread overview]
Message-ID: <20200205081210-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20200205125648.GV23346@mellanox.com>
On Wed, Feb 05, 2020 at 08:56:48AM -0400, Jason Gunthorpe wrote:
> On Wed, Feb 05, 2020 at 03:50:14PM +0800, Jason Wang wrote:
> > > Would it be better for the map/umnap logic to happen inside each device ?
> > > Devices that needs the IOMMU will call iommu APIs from inside the driver callback.
> >
> > Technically, this can work. But if it can be done by vhost-vpda it will make
> > the vDPA driver more compact and easier to be implemented.
>
> Generally speaking, in the kernel, it is normal to not hoist code of
> out drivers into subsystems until 2-3 drivers are duplicating that
> code. It helps ensure the right design is used
>
> Jason
That's up to the sybsystem maintainer really, as there's also some
intuition involved in guessing a specific API is widely useful.
In-kernel APIs are flexible, if we find something isn't needed we just
drop it.
--
MST
next prev parent reply other threads:[~2020-02-05 13:14 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-31 3:36 [PATCH] vhost: introduce vDPA based backend Tiwei Bie
2020-01-31 3:56 ` Randy Dunlap
2020-01-31 5:12 ` Randy Dunlap
2020-01-31 5:54 ` Tiwei Bie
2020-01-31 5:52 ` Tiwei Bie
2020-02-04 3:30 ` Jason Wang
2020-02-04 6:01 ` Michael S. Tsirkin
2020-02-04 6:01 ` Michael S. Tsirkin
2020-02-04 6:46 ` Jason Wang
2020-02-05 2:05 ` Tiwei Bie
2020-02-05 3:12 ` Jason Wang
2020-02-05 5:31 ` Michael S. Tsirkin
2020-02-05 5:50 ` Jason Wang
2020-02-05 5:50 ` Jason Wang
2020-02-05 6:30 ` Michael S. Tsirkin
2020-02-05 6:49 ` Jason Wang
2020-02-05 6:49 ` Jason Wang
2020-02-05 7:16 ` Michael S. Tsirkin
2020-02-05 7:42 ` Jason Wang
2020-02-05 9:22 ` Michael S. Tsirkin
2020-02-05 2:02 ` Tiwei Bie
2020-02-05 3:11 ` Jason Wang
2020-02-05 7:15 ` Shahaf Shuler
2020-02-05 7:15 ` Shahaf Shuler
2020-02-05 7:50 ` Jason Wang
2020-02-05 7:50 ` Jason Wang
2020-02-05 9:23 ` Michael S. Tsirkin
2020-02-05 9:23 ` Michael S. Tsirkin
2020-02-06 3:07 ` Jason Wang
2020-02-06 3:07 ` Jason Wang
2020-02-05 9:30 ` Shahaf Shuler
2020-02-05 9:30 ` Shahaf Shuler
2020-02-05 10:33 ` Michael S. Tsirkin
2020-02-05 10:33 ` Michael S. Tsirkin
2020-02-06 3:09 ` Jason Wang
2020-02-06 3:09 ` Jason Wang
2020-02-06 3:04 ` Jason Wang
2020-02-06 3:04 ` Jason Wang
2020-02-05 12:56 ` Jason Gunthorpe
2020-02-05 12:56 ` Jason Gunthorpe
2020-02-05 13:14 ` Michael S. Tsirkin [this message]
2020-02-05 13:14 ` Michael S. Tsirkin
2020-02-06 3:11 ` Jason Wang
2020-02-06 3:11 ` Jason Wang
2020-02-06 3:21 ` Zhu Lingshan
2020-02-06 3:21 ` Zhu Lingshan
2020-02-18 13:53 ` Jason Gunthorpe
2020-02-19 2:52 ` Tiwei Bie
2020-02-19 13:11 ` Jason Gunthorpe
2020-02-20 2:42 ` Tiwei Bie
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