>-----Original Message-----
>From: Markus Armbruster <[email protected]>
>Sent: Thursday, October 26, 2023 9:28 PM
>Subject: Re: [PATCH v3 24/37] backends/iommufd: Introduce the iommufd object
>
>Zhenzhong Duan <[email protected]> writes:
>
>> From: Eric Auger <[email protected]>
>>
>> Introduce an iommufd object which allows the interaction
>> with the host /dev/iommu device.
>>
>> The /dev/iommu can have been already pre-opened outside of qemu,
>> in which case the fd can be passed directly along with the
>> iommufd object:
>>
>> This allows the iommufd object to be shared accross several
>> subsystems (VFIO, VDPA, ...). For example, libvirt would open
>> the /dev/iommu once.
>>
>> If no fd is passed along with the iommufd object, the /dev/iommu
>> is opened by the qemu code.
>>
>> The CONFIG_IOMMUFD option must be set to compile this new object.
>>
>> Suggested-by: Alex Williamson <[email protected]>
>> Signed-off-by: Eric Auger <[email protected]>
>> Signed-off-by: Yi Liu <[email protected]>
>> Signed-off-by: Zhenzhong Duan <[email protected]>
>> Signed-off-by: Cédric Le Goater <[email protected]>
>> ---
>> MAINTAINERS | 7 +
>> qapi/qom.json | 20 +++
>> include/sysemu/iommufd.h | 46 +++++++
>> backends/iommufd-stub.c | 59 +++++++++
>> backends/iommufd.c | 268 +++++++++++++++++++++++++++++++++++++++
>> backends/Kconfig | 4 +
>> backends/meson.build | 5 +
>> backends/trace-events | 12 ++
>> qemu-options.hx | 13 ++
>> 9 files changed, 434 insertions(+)
>> create mode 100644 include/sysemu/iommufd.h
>> create mode 100644 backends/iommufd-stub.c
>> create mode 100644 backends/iommufd.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 7f9912baa0..7aa57ab16f 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -2109,6 +2109,13 @@ F: hw/vfio/ap.c
>> F: docs/system/s390x/vfio-ap.rst
>> L: [email protected]
>>
>> +iommufd
>> +M: Yi Liu <[email protected]>
>> +M: Eric Auger <[email protected]>
>> +S: Supported
>> +F: backends/iommufd.c
>> +F: include/sysemu/iommufd.h
>> +
>> vhost
>> M: Michael S. Tsirkin <[email protected]>
>> S: Supported
>> diff --git a/qapi/qom.json b/qapi/qom.json
>> index c53ef978ff..ef0b50f107 100644
>> --- a/qapi/qom.json
>> +++ b/qapi/qom.json
>> @@ -794,6 +794,22 @@
>> { 'struct': 'VfioUserServerProperties',
>> 'data': { 'socket': 'SocketAddress', 'device': 'str' } }
>>
>> +##
>> +# @IOMMUFDProperties:
>> +#
>> +# Properties for iommufd objects.
>> +#
>> +# @fd: file descriptor name previously passed via 'getfd' command,
>> +# which represents a pre-opened /dev/iommu. This allows the
>
>Two spaces between sentences for consistency, please.
Presume you mean " 'data': { '*fd': 'str' } }" line, not above line.
>
>> +# iommufd object to be shared accross several subsystems
>> +# (VFIO, VDPA, ...) and file descriptor to be shared with
>
>Comma before "and file".
>
>Either "the file descriptor", or "file descriptors".
>
>> +# other process, e.g: DPDK.
>
>e.g.
>
>Alternatively "such as DPDK."
Will fix.
>
>> +#
>> +# Since: 8.2
>> +##
>> +{ 'struct': 'IOMMUFDProperties',
>> + 'data': { '*fd': 'str' } }
>
>@fd is optional. How does the iommufd object behave when @fd is absent?
If no fd is passed along with the iommufd object, the /dev/iommu
is opened by the qemu code. Let me know if this also needs to be documented.
>
>> +
>> ##
>> # @RngProperties:
>> #
>> @@ -934,6 +950,8 @@
> ##
> # @ObjectType:
>
>None of the enum members are documented. I'm not asking you to fix that
>now.
>
> #
> # Features:
> #
> # @unstable: Member @x-remote-object is experimental.
> #
> # Since: 6.0
> ##
> { 'enum': 'ObjectType',
> 'data': [
> [...]
>> 'input-barrier',
>> { 'name': 'input-linux',
>> 'if': 'CONFIG_LINUX' },
>> + { 'name': 'iommufd',
>> + 'if': 'CONFIG_IOMMUFD' },
>
>Should struct IOMMUFDProperties also have 'if': 'CONFIG_IOMMUFD'?
Yes, thanks for point out, will fix.
BRs.
Zhenzhong
