linux-kernel - [PATCH v2 0/3] iommufd: Remove iommufd_hw_pagetable_has

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <cover.1674939002.git.nicolinc@nvidia.com>
Date:   Sat, 28 Jan 2023 13:18:08 -0800
From:   Nicolin Chen <nicolinc@...dia.com>
To:     <jgg@...dia.com>, <kevin.tian@...el.com>
CC:     <yi.l.liu@...el.com>, <iommu@...ts.linux.dev>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 0/3] iommufd: Remove iommufd_hw_pagetable_has_group

The iommufd_hw_pagetable_has_group is not a device-centric API and has
been a bit of a hack. And it needs to keep tracking an attached device
list on the hw_pagetable, and a device lock to protect the device list.

However, the coming domain replacement series can overcomplicate this
list/lock solution, especially to handle nested hw_pagetable use cases.
So, as a preparatory series, remove the device list/lock and also fix
the iommufd_hw_pagetable_has_group hack.

The iommufd_hw_pagetable_has_group() using the device list could be
replaced with a domain-pointer comparison between the hwpt->domain and
iommu_get_domain_for_dev(). The piece of dependency on list_empty() of
the device list can be also replaced with a refcount. Yet, the removal
of the device lock might introduce a race condition, so the ioas mutex
can be moved as an alternative protection.

You can also find this series on Github:
https://github.com/nicolinc/iommufd/commits/remove_iommufd_hw_pagetable_has_group

Changelog
v1->v2:
 * Fixed a copy-n-paste mistake at a lockdep_assert_held() line

Thanks
Nicolin Chen

Nicolin Chen (2):
  iommufd/device: Make hwpt_list list_add/del symmetric
  iommufd/device: Change iommufd_hw_pagetable_has_group to device
    centric

Yi Liu (1):
  iommufd: Add devices_users to track the hw_pagetable usage by device

 drivers/iommu/iommufd/device.c          | 72 ++++++++++---------------
 drivers/iommu/iommufd/hw_pagetable.c    | 16 ++++--
 drivers/iommu/iommufd/iommufd_private.h |  3 +-
 3 files changed, 40 insertions(+), 51 deletions(-)

-- 
2.39.1