netdev - Re: [PATCH] vhost: introduce vDPA based backend

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200205081210-mutt-send-email-mst@kernel.org>
Date:   Wed, 5 Feb 2020 08:14:46 -0500
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     Jason Gunthorpe <jgg@...lanox.com>
Cc:     Jason Wang <jasowang@...hat.com>,
        Shahaf Shuler <shahafs@...lanox.com>,
        Tiwei Bie <tiwei.bie@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "virtualization@...ts.linux-foundation.org" 
        <virtualization@...ts.linux-foundation.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "rob.miller@...adcom.com" <rob.miller@...adcom.com>,
        "haotian.wang@...ive.com" <haotian.wang@...ive.com>,
        "eperezma@...hat.com" <eperezma@...hat.com>,
        "lulu@...hat.com" <lulu@...hat.com>,
        Parav Pandit <parav@...lanox.com>,
        "rdunlap@...radead.org" <rdunlap@...radead.org>,
        "hch@...radead.org" <hch@...radead.org>,
        Jiri Pirko <jiri@...lanox.com>,
        "hanand@...inx.com" <hanand@...inx.com>,
        "mhabets@...arflare.com" <mhabets@...arflare.com>,
        "maxime.coquelin@...hat.com" <maxime.coquelin@...hat.com>,
        "lingshan.zhu@...el.com" <lingshan.zhu@...el.com>,
        "dan.daly@...el.com" <dan.daly@...el.com>,
        "cunming.liang@...el.com" <cunming.liang@...el.com>,
        "zhihong.wang@...el.com" <zhihong.wang@...el.com>
Subject: Re: [PATCH] vhost: introduce vDPA based backend

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