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, 10 Jul 2020 16:48:07 +0100
From:   Christoph Hellwig <hch@infradead.org>
To:     Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Cc:     alex.williamson@redhat.com, herbert@gondor.apana.org.au,
        cohuck@redhat.com, nhorman@redhat.com, vdronov@redhat.com,
        bhelgaas@google.com, mark.a.chambers@intel.com,
        gordon.mcfadden@intel.com, ahsan.atta@intel.com,
        qat-linux@intel.com, kvm@vger.kernel.org,
        linux-crypto@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/5] vfio/pci: add blocklist and disable qat
Message-ID: <20200710154807.GA7292@infradead.org>
References: <20200701110302.75199-1-giovanni.cabiddu@intel.com>
 <20200701124209.GA12512@infradead.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200701124209.GA12512@infradead.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Jul 01, 2020 at 01:42:09PM +0100, Christoph Hellwig wrote:
> On Wed, Jul 01, 2020 at 12:02:57PM +0100, Giovanni Cabiddu wrote:
> > This patchset defines a blocklist of devices in the vfio-pci module and adds
> > the current generation of Intel(R) QuickAssist devices to it as they are
> > not designed to run in an untrusted environment.
> 
> How can they not be safe?  If any device is not safe to assign the
> whole vfio concept has major issues that we need to fix for real instead
> of coming up with quirk lists for specific IDs.

No answer yet:  how is this device able to bypass the IOMMU?  Don't
we have a fundamental model flaw if a random device can bypass the
IOMMU protection?  Except for an ATS bug I can't really think of a way
how a device could bypass the IOMMU, and in that case we should just
disable ATS.