Re: [PATCH v4 0/8] IOMMU: Add support for IOMMU Bypass Feature

[Xingang Wang]

Hi everyone,

Do you have any suggestions for this series of patches.

The modifications affects many modules, including new command line,
PCI modules and ACPI firmware tables.
There's modification in IORT DMAR and IVRS, both for arm and x86
platform.

I am not sure whether the modification is appropriate in all modules,
do you have any suggestions?

Thanks

Xingang

.

On 2021/5/25 11:49, Wang Xingang wrote:
> From: Xingang Wang <wangxingang5@huawei.com>
>
> These patches add support for configure bypass_iommu on/off for
> pci root bus, including primary bus and pxb root bus. At present,
> all root bus will go through iommu when iommu is configured,
> which is not flexible, because in many situations the need for using
> iommu and bypass iommu aften exists at the same time.
>
> So this add option to enable/disable bypass_iommu for primary bus
> and pxb root bus. The bypass_iommu property is set to false default,
> meaning that devcies will go through iommu if no explicit configuration
> is added. When bypass_iommu is enabled for the root bus, devices
> attached to it will bypass iommu, otherwise devices will go through
> iommu.
>
> This feature can be used in this manner:
> arm: -machine virt,iommu=smmuv3,bypass_iommu=true
> x86: -machine q35,bypass_iommu=true
> pxb: -device pxb-pcie,bus_nr=0x10,id=pci.10,bus=pcie.0,bypass_iommu=true
>
> History:
>
> v3 -> v4:
> - simplify the logic in building the IORT idmap
>
> v2 -> v3:
> - rebase on top of v6.0.0-rc4
> - Took into account Eric's comments, replace with a bypass_iommu
>    proerty
> - When building the IORT idmap, cover the whole RID space
>
> v1 -> v2:
> - rebase on top of v6.0.0-rc0
> - Fix some issues
> - Took into account Eric's comments, and remove the PCI_BUS_IOMMU flag,
>    replace it with a property in PCIHostState.
> - Add support for x86 iommu option
>
> Xingang Wang (8):
>    hw/pci/pci_host: Allow bypass iommu for pci host
>    hw/pxb: Add a bypass iommu property
>    hw/arm/virt: Add a machine option to bypass iommu for primary bus
>    hw/i386: Add a pc machine option to bypass iommu for primary bus
>    hw/pci: Add pci_bus_range to get bus number range
>    hw/arm/virt-acpi-build: Add explicit IORT idmap for smmuv3 node
>    hw/i386/acpi-build: Add explicit scope in DMAR table
>    hw/i386/acpi-build: Add bypass_iommu check when building IVRS table
>
>   hw/arm/virt-acpi-build.c            | 135 ++++++++++++++++++++++++----
>   hw/arm/virt.c                       |  26 ++++++
>   hw/i386/acpi-build.c                |  70 ++++++++++++++-
>   hw/i386/pc.c                        |  18 ++++
>   hw/pci-bridge/pci_expander_bridge.c |   3 +
>   hw/pci-host/q35.c                   |   1 +
>   hw/pci/pci.c                        |  33 ++++++-
>   hw/pci/pci_host.c                   |   2 +
>   include/hw/arm/virt.h               |   1 +
>   include/hw/i386/pc.h                |   1 +
>   include/hw/pci/pci.h                |   2 +
>   include/hw/pci/pci_host.h           |   1 +
>   12 files changed, 270 insertions(+), 23 deletions(-)