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 v6 05/14] iommufd: Add IOMMUFD_OBJ_VEVENTQ and IOMMUFD_CMD_VEVENTQ_ALLOC
Date: Tue, 18 Feb 2025 11:29:59 -0400 [thread overview]
Message-ID: <20250218152959.GB4099685@nvidia.com> (raw)
In-Reply-To: <2fb8d9c7b01ad36b42849283cd33d931f11092cb.1737754129.git.nicolinc@nvidia.com>
On Fri, Jan 24, 2025 at 04:30:34PM -0800, Nicolin Chen wrote:
> + list_add_tail(&vevent->node, &eventq->deliver);
> + vevent->on_list = true;
> + vevent->header.sequence = atomic_read(&veventq->sequence);
> + if (atomic_read(&veventq->sequence) == INT_MAX)
> + atomic_set(&veventq->sequence, 0);
> + else
> + atomic_inc(&veventq->sequence);
> + spin_unlock(&eventq->lock);
This is all locked, we don't need veventq->sequence to be an atomic?
The bounding can be done with some simple math:
veventq->sequence = (veventq->sequence + 1) & INT_MAX;
> +static struct iommufd_vevent *
> +iommufd_veventq_deliver_fetch(struct iommufd_veventq *veventq)
> +{
> + struct iommufd_eventq *eventq = &veventq->common;
> + struct list_head *list = &eventq->deliver;
> + struct iommufd_vevent *vevent = NULL;
> +
> + spin_lock(&eventq->lock);
> + if (!list_empty(list)) {
> + vevent = list_first_entry(list, struct iommufd_vevent, node);
> + list_del(&vevent->node);
> + vevent->on_list = false;
> + }
> + /* Make a copy of the overflow node for copy_to_user */
> + if (vevent == &veventq->overflow) {
> + vevent = kzalloc(sizeof(*vevent), GFP_ATOMIC);
> + if (vevent)
> + memcpy(vevent, &veventq->overflow, sizeof(*vevent));
> + }
This error handling is wonky, if we can't allocate then we shouldn't
have done the list_del. Just return NULL which will cause
iommufd_veventq_fops_read() to exist and userspace will try again.
> @@ -403,6 +531,10 @@ static int iommufd_eventq_fops_release(struct inode *inode, struct file *filep)
> {
> struct iommufd_eventq *eventq = filep->private_data;
>
> + if (eventq->obj.type == IOMMUFD_OBJ_VEVENTQ) {
> + atomic_set(&eventq_to_veventq(eventq)->sequence, 0);
> + atomic_set(&eventq_to_veventq(eventq)->num_events, 0);
> + }
Why? We are about to free the memory?
> +int iommufd_veventq_alloc(struct iommufd_ucmd *ucmd)
> +{
> + struct iommu_veventq_alloc *cmd = ucmd->cmd;
> + struct iommufd_veventq *veventq;
> + struct iommufd_viommu *viommu;
> + int fdno;
> + int rc;
> +
> + if (cmd->flags || cmd->type == IOMMU_VEVENTQ_TYPE_DEFAULT)
> + return -EOPNOTSUPP;
> + if (!cmd->veventq_depth)
> + return -EINVAL;
Check __reserved for 0 too
Jason
next prev parent reply other threads:[~2025-02-18 15:30 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-25 0:30 [PATCH v6 00/14] iommufd: Add vIOMMU infrastructure (Part-3: vEVENTQ) Nicolin Chen
2025-01-25 0:30 ` [PATCH v6 01/14] iommufd/fault: Move two fault functions out of the header Nicolin Chen
2025-02-14 20:15 ` Jason Gunthorpe
2025-02-18 5:05 ` Tian, Kevin
2025-01-25 0:30 ` [PATCH v6 02/14] iommufd/fault: Add an iommufd_fault_init() helper Nicolin Chen
2025-01-25 0:30 ` [PATCH v6 03/14] iommufd: Abstract an iommufd_eventq from iommufd_fault Nicolin Chen
2025-02-14 20:23 ` Jason Gunthorpe
2025-01-25 0:30 ` [PATCH v6 04/14] iommufd: Rename fault.c to eventq.c Nicolin Chen
2025-01-25 0:30 ` [PATCH v6 05/14] iommufd: Add IOMMUFD_OBJ_VEVENTQ and IOMMUFD_CMD_VEVENTQ_ALLOC Nicolin Chen
2025-02-18 5:13 ` Tian, Kevin
2025-02-18 17:53 ` Nicolin Chen
2025-02-18 15:29 ` Jason Gunthorpe [this message]
2025-02-18 17:47 ` Nicolin Chen
2025-02-18 18:08 ` Jason Gunthorpe
2025-02-18 18:15 ` Nicolin Chen
2025-01-25 0:30 ` [PATCH v6 06/14] iommufd/viommu: Add iommufd_viommu_get_vdev_id helper Nicolin Chen
2025-02-18 15:31 ` Jason Gunthorpe
2025-02-20 5:17 ` Nicolin Chen
2025-02-20 16:19 ` Jason Gunthorpe
2025-01-25 0:30 ` [PATCH v6 07/14] iommufd/viommu: Add iommufd_viommu_report_event helper Nicolin Chen
2025-02-18 5:14 ` Tian, Kevin
2025-02-18 15:35 ` Jason Gunthorpe
2025-02-19 6:58 ` Tian, Kevin
2025-02-20 21:16 ` Nicolin Chen
2025-02-21 4:27 ` Tian, Kevin
2025-02-21 13:39 ` Jason Gunthorpe
2025-01-25 0:30 ` [PATCH v6 08/14] iommufd/selftest: Require vdev_id when attaching to a nested domain Nicolin Chen
2025-02-18 5:15 ` Tian, Kevin
2025-01-25 0:30 ` [PATCH v6 09/14] iommufd/selftest: Add IOMMU_TEST_OP_TRIGGER_VEVENT for vEVENTQ coverage Nicolin Chen
2025-02-18 5:16 ` Tian, Kevin
2025-01-25 0:30 ` [PATCH v6 10/14] iommufd/selftest: Add IOMMU_VEVENTQ_ALLOC test coverage Nicolin Chen
2025-02-18 5:19 ` Tian, Kevin
2025-01-25 0:30 ` [PATCH v6 11/14] Documentation: userspace-api: iommufd: Update FAULT and VEVENTQ Nicolin Chen
2025-01-28 8:21 ` Bagas Sanjaya
2025-02-18 17:02 ` Jason Gunthorpe
2025-01-25 0:30 ` [PATCH v6 12/14] iommu/arm-smmu-v3: Introduce struct arm_smmu_vmaster Nicolin Chen
2025-02-18 17:08 ` Jason Gunthorpe
2025-02-20 7:16 ` Nicolin Chen
2025-01-25 0:30 ` [PATCH v6 13/14] iommu/arm-smmu-v3: Report events that belong to devices attached to vIOMMU Nicolin Chen
2025-02-18 5:21 ` Tian, Kevin
2025-02-18 17:18 ` Jason Gunthorpe
2025-02-18 18:28 ` Nicolin Chen
2025-02-18 18:50 ` Jason Gunthorpe
2025-02-18 19:02 ` Nicolin Chen
2025-02-18 19:08 ` Jason Gunthorpe
2025-02-18 19:27 ` Nicolin Chen
2025-02-20 20:45 ` Nicolin Chen
2025-02-20 23:24 ` Jason Gunthorpe
2025-02-21 8:10 ` Nicolin Chen
2025-01-25 0:30 ` [PATCH v6 14/14] iommu/arm-smmu-v3: Set MEV bit in nested STE for DoS mitigations Nicolin Chen
2025-02-18 5:24 ` Tian, Kevin
2025-02-18 18:17 ` Pranjal Shrivastava
2025-02-18 18:52 ` Jason Gunthorpe
2025-02-20 7:12 ` Nicolin Chen
2025-02-18 18:53 ` Nicolin Chen
2025-02-20 16:15 ` Pranjal Shrivastava
2025-02-18 17:21 ` Jason Gunthorpe
2025-02-18 18:14 ` Nicolin Chen
2025-02-20 9:09 ` Nicolin Chen
2025-02-14 8:03 ` [PATCH v6 00/14] iommufd: Add vIOMMU infrastructure (Part-3: vEVENTQ) Nicolin Chen
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=20250218152959.GB4099685@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.