Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 24 Jul 2020 09:25:09 +0200
From:   Stefano Garzarella <sgarzare@redhat.com>
To:     Colin Walters <walters@verbum.org>
Cc:     Andy Lutomirski <luto@kernel.org>, Jens Axboe <axboe@kernel.dk>,
        Christoph Hellwig <hch@lst.de>,
        Kees Cook <keescook@chromium.org>,
        Pavel Begunkov <asml.silence@gmail.com>,
        Miklos Szeredi <miklos@szeredi.hu>,
        Matthew Wilcox <willy@infradead.org>,
        Jann Horn <jannh@google.com>,
        Christian Brauner <christian.brauner@ubuntu.com>,
        strace-devel@lists.strace.io, io-uring@vger.kernel.org,
        Linux API <linux-api@vger.kernel.org>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: strace of io_uring events?
Message-ID: <20200724072509.sgqlbuocpo2peian@steredhat.lan>
References: <7c09f6af-653f-db3f-2378-02dca2bc07f7@gmail.com>
 <CAJfpegt9=p4uo5U2GXqc-rwqOESzZCWAkGMRTY1r8H6fuXx96g@mail.gmail.com>
 <48cc7eea-5b28-a584-a66c-4eed3fac5e76@gmail.com>
 <202007151511.2AA7718@keescook>
 <20200716131404.bnzsaarooumrp3kx@steredhat>
 <202007160751.ED56C55@keescook>
 <20200717080157.ezxapv7pscbqykhl@steredhat.lan>
 <CALCETrXSPdiVCgh3h=q7w9RyiKnp-=8jOHoFHX=an0cWqK7bzQ@mail.gmail.com>
 <20200721155848.32xtze5ntvcmjv63@steredhat>
 <d57e169a-55a0-4fa2-a7f2-9a462a786a38@www.fastmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <d57e169a-55a0-4fa2-a7f2-9a462a786a38@www.fastmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Jul 23, 2020 at 09:37:40AM -0400, Colin Walters wrote:
> On Tue, Jul 21, 2020, at 11:58 AM, Stefano Garzarella wrote:
> 
> > my use case concerns virtualization. The idea, that I described in the
> > proposal of io-uring restrictions [1], is to share io_uring CQ and SQ queues
> > with a guest VM for block operations.
> 
> Virtualization being a strong security barrier is in eternal conflict
> with maximizing performance.  All of these "let's add a special
> guest/host channel" are high risk areas.
> 
> And this effort in particular - is it *really* worth it to expose a
> brand new, fast moving Linux kernel interface (that probably hasn't
> been fuzzed as much as it needs to be) to virtual machines?
> 

It is an experiment to explore the potential of io_uring. In addition
the restrictions can also be useful for other use case, for example if
a process  wants to allow another process to use io_uring, but only allowing
a subset of operations.

> People who want maximum performance at the cost of a bit of security
> already have the choice to use Linux containers, where they can use
> io_uring natively.
> 

Thanks,
Stefano