From: Jacob Pan <jacob.jun.pan@linux.intel.com>
To: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"joro@8bytes.org" <joro@8bytes.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"jcrouse@codeaurora.org" <jcrouse@codeaurora.org>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"Jonathan.Cameron@huawei.com" <Jonathan.Cameron@huawei.com>,
"christian.koenig@amd.com" <christian.koenig@amd.com>,
"eric.auger@redhat.com" <eric.auger@redhat.com>,
"kevin.tian@intel.com" <kevin.tian@intel.com>,
"yi.l.liu@intel.com" <yi.l.liu@intel.com>,
Andrew Murray <Andrew.Murray@arm.com>,
Will Deacon <Will.Deacon@arm.com>,
Robin Murphy <Robin.Murphy@arm.com>,
"ashok.raj@intel.com" <ashok.raj@intel.com>,
"xuzaibo@huawei.com" <xuzaibo@huawei.com>,
"liguozhu@hisilicon.com" <liguozhu@hisilicon.com>,
"okaya@codeaurora.org" <okaya@codeaurora.org>,
"bharatku@xilinx.com" <bharatku@xilinx.com>,
"ilias.apalodimas@linaro.org" <ilias.apalodimas@linaro.org>,
"shunyong.yang@hxt-semitech.com" <shunyong.yang@hxt-semitech.com>,
jacob.jun.pan@linux.intel.com
Subject: Re: [PATCH v3 02/10] iommu/sva: Bind process address spaces to devices
Date: Wed, 26 Sep 2018 11:01:03 -0700 [thread overview]
Message-ID: <20180926110103.45b57f75@jacob-builder> (raw)
In-Reply-To: <7cbd503a-c79e-3c40-7388-ce6c23f7f536@arm.com>
On Mon, 24 Sep 2018 13:07:47 +0100
Jean-Philippe Brucker <jean-philippe.brucker@arm.com> wrote:
> On 23/09/2018 04:05, Lu Baolu wrote:
> > Hi,
> >
> > On 09/21/2018 01:00 AM, Jean-Philippe Brucker wrote:
> >> Add bind() and unbind() operations to the IOMMU API. Bind()
> >> returns a PASID that drivers can program in hardware, to let their
> >> devices access an mm. This patch only adds skeletons for the
> >> device driver API, most of the implementation is still missing.
> >
> > Is it possible that a malicious process can unbind a pasid which is
> > used by another normal process?
>
> Yes, it's up to the device driver that calls unbind() to check that
> the caller is allowed to unbind this PASID. We can't do it ourselves
> since unbind() could also be called from a kernel thread for example
> from a cleanup function in some workqueue, outside the context of the
> process to unbind.
>
I am wondering if we can avoid the complexity around permission
checking by simply _only_ allow bind/unbind() on current mm? what would
be the missing use cases if we bind current only?
It can also avoid other race such as unbind and mmu_notifier release
call.
> Jean
>
> >
> > It might happen in below sequence:
> >
> >
> > Process A Process B
> > ========= =========
> > iommu_sva_init_device(dev)
> > iommu_sva_bind_device(dev)
> > ....
> > device access mm of A with
> > #PASID returned above
> > ....
> > iommu_sva_unbind_device(dev, #PASID)
> > ....
> > [unrecoverable errors]
> >
> > I didn't have a thorough consideration of this. Sorry if this has
> > been prevented.
> >
> > Best regards,
> > Lu Baolu
[Jacob Pan]
next prev parent reply other threads:[~2018-09-26 18:02 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-20 17:00 [PATCH v3 00/10] Shared Virtual Addressing for the IOMMU Jean-Philippe Brucker
2018-09-20 17:00 ` [PATCH v3 01/10] iommu: Introduce Shared Virtual Addressing API Jean-Philippe Brucker
[not found] ` <f406bcf7-4e54-9f1b-88eb-03fc642ffede@linux.intel.com>
2018-09-24 12:07 ` Jean-Philippe Brucker
2018-09-25 13:16 ` Joerg Roedel
2018-09-25 22:46 ` Jacob Pan
2018-09-26 10:14 ` Jean-Philippe Brucker
2018-09-26 12:48 ` Joerg Roedel
2018-09-20 17:00 ` [PATCH v3 02/10] iommu/sva: Bind process address spaces to devices Jean-Philippe Brucker
2018-09-23 3:05 ` Lu Baolu
2018-09-24 12:07 ` Jean-Philippe Brucker
2018-09-26 18:01 ` Jacob Pan [this message]
2018-09-27 15:06 ` Jean-Philippe Brucker
2018-09-28 1:14 ` Tian, Kevin
2018-09-20 17:00 ` [PATCH v3 03/10] iommu/sva: Manage process address spaces Jean-Philippe Brucker
2018-09-25 3:15 ` Lu Baolu
2018-09-25 10:32 ` Jean-Philippe Brucker
2018-09-26 3:12 ` Lu Baolu
2018-09-25 13:26 ` Joerg Roedel
2018-09-25 23:33 ` Lu Baolu
2018-09-26 10:20 ` Jean-Philippe Brucker
2018-09-26 12:45 ` Joerg Roedel
2018-09-26 13:50 ` Jean-Philippe Brucker
2018-09-27 3:22 ` Liu, Yi L
2018-09-27 13:37 ` Jean-Philippe Brucker
2018-10-08 8:29 ` Liu, Yi L
2018-09-26 22:58 ` Jacob Pan
2018-09-26 22:35 ` Jacob Pan
2018-10-03 17:52 ` Jean-Philippe Brucker
2018-10-15 20:53 ` Jacob Pan
2018-09-20 17:00 ` [PATCH v3 04/10] iommu/sva: Add a mm_exit callback for device drivers Jean-Philippe Brucker
2018-09-20 17:00 ` [PATCH v3 05/10] iommu/sva: Track mm changes with an MMU notifier Jean-Philippe Brucker
2018-09-20 17:00 ` [PATCH v3 06/10] iommu/sva: Search mm by PASID Jean-Philippe Brucker
2018-09-25 4:59 ` Lu Baolu
2018-09-20 17:00 ` [PATCH v3 07/10] iommu: Add a page fault handler Jean-Philippe Brucker
2018-09-27 20:37 ` Jacob Pan
2018-10-03 17:46 ` Jean-Philippe Brucker
2018-09-20 17:00 ` [PATCH v3 08/10] iommu/iopf: Handle mm faults Jean-Philippe Brucker
2018-09-20 17:00 ` [PATCH v3 09/10] iommu/sva: Register page fault handler Jean-Philippe Brucker
2018-09-20 17:00 ` [RFC PATCH v3 10/10] iommu/sva: Add support for private PASIDs Jean-Philippe Brucker
2018-10-12 14:32 ` Jordan Crouse
2018-10-17 14:21 ` Jean-Philippe Brucker
2018-10-17 14:24 ` Jean-Philippe Brucker
2018-10-17 15:07 ` Jordan Crouse
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180926110103.45b57f75@jacob-builder \
--to=jacob.jun.pan@linux.intel.com \
--cc=Andrew.Murray@arm.com \
--cc=Jonathan.Cameron@huawei.com \
--cc=Robin.Murphy@arm.com \
--cc=Will.Deacon@arm.com \
--cc=alex.williamson@redhat.com \
--cc=ashok.raj@intel.com \
--cc=baolu.lu@linux.intel.com \
--cc=bharatku@xilinx.com \
--cc=christian.koenig@amd.com \
--cc=eric.auger@redhat.com \
--cc=ilias.apalodimas@linaro.org \
--cc=iommu@lists.linux-foundation.org \
--cc=jcrouse@codeaurora.org \
--cc=jean-philippe.brucker@arm.com \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=liguozhu@hisilicon.com \
--cc=linux-pci@vger.kernel.org \
--cc=okaya@codeaurora.org \
--cc=shunyong.yang@hxt-semitech.com \
--cc=xuzaibo@huawei.com \
--cc=yi.l.liu@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).