From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: kevin.tian@intel.com, corbet@lwn.net, will@kernel.org,
joro@8bytes.org, suravee.suthikulpanit@amd.com,
robin.murphy@arm.com, dwmw2@infradead.org,
baolu.lu@linux.intel.com, shuah@kernel.org,
linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
linux-arm-kernel@lists.infradead.org,
linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org,
eric.auger@redhat.com, jean-philippe@linaro.org, mdf@kernel.org,
mshavit@google.com, shameerali.kolothum.thodi@huawei.com,
smostafa@google.com, ddutile@redhat.com, yi.l.liu@intel.com,
patches@lists.linux.dev
Subject: Re: [PATCH v5 06/14] iommufd: Add IOMMUFD_OBJ_VEVENTQ and IOMMUFD_CMD_VEVENTQ_ALLOC
Date: Mon, 13 Jan 2025 15:12:25 -0400 [thread overview]
Message-ID: <20250113191225.GS5556@nvidia.com> (raw)
In-Reply-To: <Z4GX/R6lRwuhlBJQ@Asurada-Nvidia>
On Fri, Jan 10, 2025 at 01:58:21PM -0800, Nicolin Chen wrote:
> Hmm, it seems that I haven't got your first narrative straight..
>
> Would you mind elaborate "copy_to_user() can block while waiting
> on a page fault"? When would this happen?
copy_to_user() is a sleeping function that sleeps if the user memory
is non-present. So userspace can cause copy_to_user to copy to
anything, including memory that is non-present and will take along
time to page fault in. Eg perhaps by abusing userfaultfd.
We should not allow userspace to globally DOS the iommu driver this
way.
So do not hold locks that are also held by the HW event path across
copy_to_user().
Jason
next prev parent reply other threads:[~2025-01-13 19:12 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-07 17:10 [PATCH v5 00/14] iommufd: Add vIOMMU infrastructure (Part-3: vEVENTQ) Nicolin Chen
2025-01-07 17:10 ` [PATCH v5 01/14] iommufd: Keep OBJ/IOCTL lists in an alphabetical order Nicolin Chen
2025-01-10 6:26 ` Tian, Kevin
2025-01-10 17:25 ` Jason Gunthorpe
2025-01-14 19:29 ` Jason Gunthorpe
2025-01-07 17:10 ` [PATCH v5 02/14] iommufd/fault: Add an iommufd_fault_init() helper Nicolin Chen
2025-01-10 17:25 ` Jason Gunthorpe
2025-01-07 17:10 ` [PATCH v5 03/14] iommufd/fault: Move iommufd_fault_iopf_handler() to header Nicolin Chen
2025-01-10 17:25 ` Jason Gunthorpe
2025-01-07 17:10 ` [PATCH v5 04/14] iommufd: Abstract an iommufd_eventq from iommufd_fault Nicolin Chen
2025-01-10 6:26 ` Tian, Kevin
2025-01-10 17:26 ` Jason Gunthorpe
2025-01-10 20:49 ` Nicolin Chen
2025-01-07 17:10 ` [PATCH v5 05/14] iommufd: Rename fault.c to eventq.c Nicolin Chen
2025-01-10 17:27 ` Jason Gunthorpe
2025-01-07 17:10 ` [PATCH v5 06/14] iommufd: Add IOMMUFD_OBJ_VEVENTQ and IOMMUFD_CMD_VEVENTQ_ALLOC Nicolin Chen
2025-01-10 7:06 ` Tian, Kevin
2025-01-10 21:29 ` Nicolin Chen
2025-01-13 2:52 ` Tian, Kevin
2025-01-13 4:51 ` Nicolin Chen
2025-01-13 8:17 ` Tian, Kevin
2025-01-13 19:10 ` Jason Gunthorpe
2025-01-10 17:48 ` Jason Gunthorpe
2025-01-10 19:27 ` Nicolin Chen
2025-01-10 19:49 ` Jason Gunthorpe
2025-01-10 21:58 ` Nicolin Chen
2025-01-13 19:12 ` Jason Gunthorpe [this message]
2025-01-13 19:18 ` Nicolin Chen
2025-01-07 17:10 ` [PATCH v5 07/14] iommufd/viommu: Add iommufd_viommu_get_vdev_id helper Nicolin Chen
2025-01-10 7:07 ` Tian, Kevin
2025-01-10 21:35 ` Nicolin Chen
2025-01-07 17:10 ` [PATCH v5 08/14] iommufd/viommu: Add iommufd_viommu_report_event helper Nicolin Chen
2025-01-10 7:12 ` Tian, Kevin
2025-01-10 14:51 ` Jason Gunthorpe
2025-01-10 18:40 ` Nicolin Chen
2025-01-10 17:41 ` Jason Gunthorpe
2025-01-10 18:38 ` Nicolin Chen
2025-01-10 19:51 ` Jason Gunthorpe
2025-01-10 19:56 ` Nicolin Chen
2025-01-13 5:37 ` Nicolin Chen
2025-01-13 19:21 ` Jason Gunthorpe
2025-01-13 19:47 ` Nicolin Chen
2025-01-13 19:54 ` Jason Gunthorpe
2025-01-13 20:44 ` Nicolin Chen
2025-01-14 13:41 ` Jason Gunthorpe
2025-01-17 22:11 ` Nicolin Chen
2025-01-20 18:18 ` Jason Gunthorpe
2025-01-20 20:52 ` Nicolin Chen
2025-01-21 18:36 ` Jason Gunthorpe
2025-01-21 19:55 ` Nicolin Chen
2025-01-21 20:09 ` Jason Gunthorpe
2025-01-21 21:02 ` Nicolin Chen
2025-01-21 21:14 ` Jason Gunthorpe
2025-01-21 21:40 ` Nicolin Chen
2025-01-22 0:21 ` Jason Gunthorpe
2025-01-22 7:15 ` Nicolin Chen
2025-01-22 9:33 ` Tian, Kevin
2025-01-22 19:54 ` Nicolin Chen
2025-01-23 13:42 ` Jason Gunthorpe
2025-01-22 8:05 ` Nicolin Chen
2025-01-22 18:02 ` Nicolin Chen
2025-01-23 7:02 ` Nicolin Chen
2025-01-23 13:43 ` Jason Gunthorpe
2025-01-07 17:10 ` [PATCH v5 09/14] iommufd/selftest: Require vdev_id when attaching to a nested domain Nicolin Chen
2025-01-07 17:10 ` [PATCH v5 10/14] iommufd/selftest: Add IOMMU_TEST_OP_TRIGGER_VEVENT for vEVENTQ coverage Nicolin Chen
2025-01-07 17:10 ` [PATCH v5 11/14] iommufd/selftest: Add IOMMU_VEVENTQ_ALLOC test coverage Nicolin Chen
2025-01-07 17:10 ` [PATCH v5 12/14] Documentation: userspace-api: iommufd: Update FAULT and VEVENTQ Nicolin Chen
2025-01-10 7:13 ` Tian, Kevin
2025-01-07 17:10 ` [PATCH v5 13/14] iommu/arm-smmu-v3: Introduce struct arm_smmu_vmaster Nicolin Chen
2025-01-13 19:29 ` Jason Gunthorpe
2025-01-13 19:52 ` Nicolin Chen
2025-01-07 17:10 ` [PATCH v5 14/14] iommu/arm-smmu-v3: Report events that belong to devices attached to vIOMMU Nicolin Chen
2025-01-09 11:04 ` kernel test robot
2025-01-13 19:01 ` Nicolin Chen
2025-01-13 19:06 ` Jason Gunthorpe
2025-01-13 19:15 ` Nicolin Chen
2025-01-13 19:18 ` Jason Gunthorpe
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=20250113191225.GS5556@nvidia.com \
--to=jgg@nvidia.com \
--cc=baolu.lu@linux.intel.com \
--cc=corbet@lwn.net \
--cc=ddutile@redhat.com \
--cc=dwmw2@infradead.org \
--cc=eric.auger@redhat.com \
--cc=iommu@lists.linux.dev \
--cc=jean-philippe@linaro.org \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=mdf@kernel.org \
--cc=mshavit@google.com \
--cc=nicolinc@nvidia.com \
--cc=patches@lists.linux.dev \
--cc=robin.murphy@arm.com \
--cc=shameerali.kolothum.thodi@huawei.com \
--cc=shuah@kernel.org \
--cc=smostafa@google.com \
--cc=suravee.suthikulpanit@amd.com \
--cc=will@kernel.org \
--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).