From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>,
Alex Williamson <alex.williamson@redhat.com>
Cc: baolu.lu@linux.intel.com, Robin Murphy <robin.murphy@arm.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
Cornelia Huck <cohuck@redhat.com>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Dave Jiang <dave.jiang@intel.com>, Liu Yi L <yi.l.liu@intel.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org
Subject: Re: [PATCH v3 0/4] iommu aux-domain APIs extensions
Date: Thu, 23 Jul 2020 21:55:59 +0800 [thread overview]
Message-ID: <f5f3e7bc-6c88-5680-ad6f-f1eb721a7445@linux.intel.com> (raw)
In-Reply-To: <20200714055703.5510-1-baolu.lu@linux.intel.com>
Hi Joerg and Alex,
Any comments for this series?
Just check to see whether we could make it for v5.9. The first aux-
domain capable device driver has been posted [1].
[1]
https://lore.kernel.org/linux-pci/159534667974.28840.2045034360240786644.stgit@djiang5-desk3.ch.intel.com/
Best regards,
baolu
On 2020/7/14 13:56, Lu Baolu wrote:
> This series aims to extend the IOMMU aux-domain API set so that it
> could be more friendly to vfio/mdev usage. The interactions between
> vfio/mdev and iommu during mdev creation and passthr are:
>
> 1. Create a group for mdev with iommu_group_alloc();
> 2. Add the device to the group with
>
> group = iommu_group_alloc();
> if (IS_ERR(group))
> return PTR_ERR(group);
>
> ret = iommu_group_add_device(group, &mdev->dev);
> if (!ret)
> dev_info(&mdev->dev, "MDEV: group_id = %d\n",
> iommu_group_id(group));
>
> 3. Allocate an aux-domain with iommu_domain_alloc();
> 4. Attach the aux-domain to the iommu_group.
>
> iommu_group_for_each_dev {
> if (iommu_dev_feature_enabled(iommu_device, IOMMU_DEV_FEAT_AUX))
> return iommu_aux_attach_device(domain, iommu_device);
> else
> return iommu_attach_device(domain, iommu_device);
> }
>
> where, iommu_device is the aux-domain-capable device. The mdev's in
> the group are all derived from it.
>
> In the whole process, an iommu group was allocated for the mdev and an
> iommu domain was attached to the group, but the group->domain leaves
> NULL. As the result, iommu_get_domain_for_dev() (or other similar
> interfaces) doesn't work anymore.
>
> The iommu_get_domain_for_dev() is a necessary interface for device
> drivers that want to support vfio/mdev based aux-domain. For example,
>
> unsigned long pasid;
> struct iommu_domain *domain;
> struct device *dev = mdev_dev(mdev);
> struct device *iommu_device = vfio_mdev_get_iommu_device(dev);
>
> domain = iommu_get_domain_for_dev(dev);
> if (!domain)
> return -ENODEV;
>
> pasid = iommu_aux_get_pasid(domain, iommu_device);
> if (pasid <= 0)
> return -EINVAL;
>
> /* Program the device context */
> ....
>
> We tried to address this by extending iommu_aux_at(de)tach_device() so that
> the users could pass in an optional device pointer (for example vfio/mdev).
> (v2 of this series)
>
> https://lore.kernel.org/linux-iommu/20200707013957.23672-1-baolu.lu@linux.intel.com/
>
> But that will cause a lock issue as group->mutex has been applied in
> iommu_group_for_each_dev(), but has to be reapplied again in the
> iommu_aux_attach_device().
>
> This version tries to address this by introducing two new APIs into the
> aux-domain API set:
>
> /**
> * iommu_aux_attach_group - attach an aux-domain to an iommu_group which
> * contains sub-devices (for example mdevs)
> * derived from @dev.
> * @domain: an aux-domain;
> * @group: an iommu_group which contains sub-devices derived from @dev;
> * @dev: the physical device which supports IOMMU_DEV_FEAT_AUX.
> *
> * Returns 0 on success, or an error value.
> */
> int iommu_aux_attach_group(struct iommu_domain *domain,
> struct iommu_group *group, struct device *dev)
>
> /**
> * iommu_aux_detach_group - detach an aux-domain from an iommu_group
> *
> * @domain: an aux-domain;
> * @group: an iommu_group which contains sub-devices derived from @dev;
> * @dev: the physical device which supports IOMMU_DEV_FEAT_AUX.
> *
> * @domain must have been attached to @group via
> * iommu_aux_attach_group().
> */
> void iommu_aux_detach_group(struct iommu_domain *domain,
> struct iommu_group *group, struct device *dev)
>
> This version is evolved according to feedbacks from Robin(v1) and
> Alex(v2). Your comments are very appreciated.
>
> Best regards,
> baolu
>
> ---
> Change log:
> - v1->v2:
> - https://lore.kernel.org/linux-iommu/20200627031532.28046-1-baolu.lu@linux.intel.com/
> - Suggested by Robin.
>
> - v2->v3:
> - https://lore.kernel.org/linux-iommu/20200707013957.23672-1-baolu.lu@linux.intel.com/
> - Suggested by Alex
>
> Lu Baolu (4):
> iommu: Check IOMMU_DEV_FEAT_AUX feature in aux api's
> iommu: Add iommu_aux_at(de)tach_group()
> iommu: Add iommu_aux_get_domain_for_dev()
> vfio/type1: Use iommu_aux_at(de)tach_group() APIs
>
> drivers/iommu/iommu.c | 92 ++++++++++++++++++++++++++++++---
> drivers/vfio/vfio_iommu_type1.c | 44 +++-------------
> include/linux/iommu.h | 24 +++++++++
> 3 files changed, 116 insertions(+), 44 deletions(-)
>
prev parent reply other threads:[~2020-07-23 13:56 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 5:56 [PATCH v3 0/4] iommu aux-domain APIs extensions Lu Baolu
2020-07-14 5:57 ` [PATCH v3 1/4] iommu: Check IOMMU_DEV_FEAT_AUX feature in aux api's Lu Baolu
2020-07-29 20:03 ` Alex Williamson
2020-07-30 1:46 ` Lu Baolu
2020-07-14 5:57 ` [PATCH v3 2/4] iommu: Add iommu_aux_at(de)tach_group() Lu Baolu
2020-07-14 16:39 ` Jacob Pan
2020-07-15 0:47 ` Lu Baolu
2020-07-15 16:01 ` Jacob Pan
2020-07-16 1:07 ` Lu Baolu
2020-07-29 20:03 ` Alex Williamson
2020-07-29 23:34 ` Tian, Kevin
2020-07-30 19:46 ` Alex Williamson
2020-07-31 5:47 ` Lu Baolu
2020-07-31 18:05 ` Alex Williamson
2020-08-03 1:57 ` Lu Baolu
2020-07-14 5:57 ` [PATCH v3 3/4] iommu: Add iommu_aux_get_domain_for_dev() Lu Baolu
2020-07-29 20:25 ` Alex Williamson
2020-07-29 23:49 ` Tian, Kevin
2020-07-30 20:17 ` Alex Williamson
2020-07-31 0:26 ` Tian, Kevin
2020-07-31 2:17 ` Tian, Kevin
2020-07-31 6:30 ` Lu Baolu
2020-07-31 18:14 ` Alex Williamson
2020-08-03 2:15 ` Lu Baolu
2020-07-14 5:57 ` [PATCH v3 4/4] vfio/type1: Use iommu_aux_at(de)tach_group() APIs Lu Baolu
2020-07-14 8:25 ` Christoph Hellwig
2020-07-14 16:29 ` Jacob Pan
2020-07-15 1:00 ` Lu Baolu
2020-07-15 1:23 ` Tian, Kevin
2020-07-29 20:32 ` Alex Williamson
2020-07-30 2:41 ` Lu Baolu
2020-07-30 21:17 ` Alex Williamson
2020-07-31 1:37 ` Lu Baolu
2020-07-30 9:36 ` Liu, Yi L
2020-07-31 1:39 ` Lu Baolu
2020-07-23 13:55 ` Lu Baolu [this message]
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=f5f3e7bc-6c88-5680-ad6f-f1eb721a7445@linux.intel.com \
--to=baolu.lu@linux.intel.com \
--cc=alex.williamson@redhat.com \
--cc=ashok.raj@intel.com \
--cc=cohuck@redhat.com \
--cc=dave.jiang@intel.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jean-philippe@linaro.org \
--cc=joro@8bytes.org \
--cc=kevin.tian@intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=robin.murphy@arm.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).