From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Bjorn Helgaas <bhelgaas@google.com>
Cc: ashok.raj@intel.com, jacob.jun.pan@intel.com,
kevin.tian@intel.com, Christoph Hellwig <hch@lst.de>,
Robin Murphy <robin.murphy@arm.com>,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
Lu Baolu <baolu.lu@linux.intel.com>
Subject: [RFC PATCH 0/4] iommu: Per-group default domain type
Date: Wed, 1 Jan 2020 13:26:44 +0800 [thread overview]
Message-ID: <20200101052648.14295-1-baolu.lu@linux.intel.com> (raw)
An IOMMU group represents the smallest set of devices that are considered
to be isolated. All devices belonging to an IOMMU group share a default
domain for DMA APIs. There are two types of default domain: IOMMU_DOMAIN_DMA
and IOMMU_DOMAIN_IDENTITY. The former means IOMMU translation, while the
latter means IOMMU by-pass.
Currently, the default domain type for the IOMMU groups is determined
globally. All IOMMU groups use a single default domain type. The global
default domain type can be adjusted by kernel build configuration or
kernel parameters.
More and more users are looking forward to a fine grained default domain
type. For example, with the global default domain type set to translation,
the OEM verndors or end users might want some trusted and fast-speed devices
to bypass IOMMU for performance gains. On the other hand, with global
default domain type set to by-pass, some devices with limited system
memory addressing capability might want IOMMU translation to remove the
bounce buffer overhead.
This series proposes per-group default domain type to meet these demands.
It adds a per-device iommu_passthrough attribute. By setting this
attribute, end users or device vendors are able to tell the IOMMU subsystem
that this device is willing to use a default domain of IOMMU_DOMAIN_IDENTITY.
The IOMMU device probe procedure is reformed to pre-allocate groups for
all devices on a specific bus before adding the devices into the groups.
This enables the IOMMU device probe precedure to determine a per-group
default domain type before allocating IOMMU domains and attaching them
to devices.
Please help to review it. Your comments and suggestions are appricated.
Best regards,
baolu
Lu Baolu (4):
driver core: Add iommu_passthrough to struct device
PCI: Add "pci=iommu_passthrough=" parameter for iommu passthrough
iommu: Preallocate iommu group when probing devices
iommu: Determine default domain type before allocating domain
.../admin-guide/kernel-parameters.txt | 5 +
drivers/iommu/iommu.c | 127 ++++++++++++++----
drivers/pci/pci.c | 34 +++++
drivers/pci/pci.h | 1 +
drivers/pci/probe.c | 2 +
include/linux/device.h | 3 +
6 files changed, 143 insertions(+), 29 deletions(-)
--
2.17.1
next reply other threads:[~2020-01-01 5:28 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-01 5:26 Lu Baolu [this message]
2020-01-01 5:26 ` [RFC PATCH 1/4] driver core: Add iommu_passthrough to struct device Lu Baolu
2020-01-01 5:26 ` [RFC PATCH 2/4] PCI: Add "pci=iommu_passthrough=" parameter for iommu passthrough Lu Baolu
2020-01-18 0:18 ` Bjorn Helgaas
2020-01-18 2:04 ` Lu Baolu
2020-01-21 14:17 ` Bjorn Helgaas
2020-01-22 4:49 ` Lu Baolu
2020-01-01 5:26 ` [RFC PATCH 3/4] iommu: Preallocate iommu group when probing devices Lu Baolu
2020-01-17 10:21 ` Joerg Roedel
2020-01-18 2:18 ` Lu Baolu
2020-01-19 6:29 ` Lu Baolu
2020-01-21 12:45 ` Robin Murphy
2020-01-22 5:39 ` Lu Baolu
2020-01-23 14:55 ` Robin Murphy
2020-01-01 5:26 ` [RFC PATCH 4/4] iommu: Determine default domain type before allocating domain Lu Baolu
2020-01-20 9:44 ` [RFC PATCH 0/4] iommu: Per-group default domain type John Garry
2020-01-21 0:43 ` Lu Baolu
2020-01-21 10:14 ` John Garry
2020-01-22 4:58 ` Lu Baolu
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