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
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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: kevin.tian@intel.com, ashok.raj@intel.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, jacob.jun.pan@intel.com, Robin Murphy <robin.murphy@arm.com>, Christoph Hellwig <hch@lst.de> 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 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next reply other threads:[~2020-01-01 5:28 UTC|newest] Thread overview: 38+ 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 0/4] iommu: Per-group default domain type Lu Baolu 2020-01-01 5:26 ` [RFC PATCH 1/4] driver core: Add iommu_passthrough to struct device Lu Baolu 2020-01-01 5:26 ` Lu Baolu 2020-01-01 5:26 ` [RFC PATCH 2/4] PCI: Add "pci=iommu_passthrough=" parameter for iommu passthrough Lu Baolu 2020-01-01 5:26 ` Lu Baolu 2020-01-18 0:18 ` Bjorn Helgaas 2020-01-18 0:18 ` Bjorn Helgaas 2020-01-18 2:04 ` Lu Baolu 2020-01-18 2:04 ` Lu Baolu 2020-01-21 14:17 ` Bjorn Helgaas 2020-01-21 14:17 ` Bjorn Helgaas 2020-01-22 4:49 ` Lu Baolu 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 2020-01-01 5:26 ` Lu Baolu 2020-01-17 10:21 ` Joerg Roedel 2020-01-17 10:21 ` Joerg Roedel 2020-01-18 2:18 ` Lu Baolu 2020-01-18 2:18 ` Lu Baolu 2020-01-19 6:29 ` Lu Baolu 2020-01-19 6:29 ` Lu Baolu 2020-01-21 12:45 ` Robin Murphy 2020-01-21 12:45 ` Robin Murphy 2020-01-22 5:39 ` Lu Baolu 2020-01-22 5:39 ` Lu Baolu 2020-01-23 14:55 ` Robin Murphy 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 2020-01-01 5:26 ` Lu Baolu 2020-01-20 9:44 ` [RFC PATCH 0/4] iommu: Per-group default domain type John Garry 2020-01-20 9:44 ` John Garry 2020-01-21 0:43 ` Lu Baolu 2020-01-21 0:43 ` Lu Baolu 2020-01-21 10:14 ` John Garry 2020-01-21 10:14 ` John Garry 2020-01-22 4:58 ` Lu Baolu 2020-01-22 4:58 ` Lu Baolu
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