From: "Liu, Yi L" <yi.l.liu@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>,
Alex Williamson <alex.williamson@redhat.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
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"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
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<shameerali.kolothum.thodi@huawei.com>,
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"Hao, Xudong" <xudong.hao@intel.com>,
"Zhao, Yan Y" <yan.y.zhao@intel.com>,
"Xu, Terrence" <terrence.xu@intel.com>,
"Jiang, Yanting" <yanting.jiang@intel.com>
Subject: RE: [PATCH v8 21/24] vfio: Add VFIO_DEVICE_BIND_IOMMUFD
Date: Thu, 30 Mar 2023 12:52:39 +0000 [thread overview]
Message-ID: <DS0PR11MB7529B03CED8FE7BCA284F789C38E9@DS0PR11MB7529.namprd11.prod.outlook.com> (raw)
In-Reply-To: <ZCTIJScfgbWWguD5@nvidia.com>
> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Thursday, March 30, 2023 7:22 AM
>
> On Wed, Mar 29, 2023 at 03:00:55PM -0600, Alex Williamson wrote:
>
> > > + * The user should provide a device cookie when calling this ioctl. The
> > > + * cookie is carried only in event e.g. I/O fault reported to userspace
> > > + * via iommufd. The user should use devid returned by this ioctl to mark
> > > + * the target device in other ioctls (e.g. iommu hardware infomration query
> > > + * via iommufd, and etc.).
> >
> > AFAICT, the whole concept of this dev_cookie is a fantasy. It only
> > exists in this series in these comments and the structure below. It's
> > not even defined whether it needs to be unique within an iommufd
> > context, and clearly nothing here validates that. There's not enough
> > implementation for it to exist in this series. Maybe dev_cookie is
> > appended to the end of the structure and indicated with a flag when it
> > has some meaning.
>
> Yes, I've asked for this to be punted to the PRI series enough times
> already, why does it keep coming back ??
yes, I promise to remove it in next version.
> > > + * @argsz: user filled size of this data.
> > > + * @flags: reserved for future extension.
> > > + * @dev_cookie: a per device cookie provided by userspace.
> > > + * @iommufd: iommufd to bind. a negative value means noiommu.
> >
> > "Use a negative value for no-iommu, where supported", or better, should
> > we define this explicitly as -1, or why not use a flag bit to specify
> > no-iommu? Maybe minsz is only through flags for the noiommu use case.
>
> I was happy enough for this to be defined as -1. We could give it a
> formal sounding constant too
are you suggesting having something like "#define VFIO_NOIOMMU_FD -1"?
Regards,
Yi Liu
next prev parent reply other threads:[~2023-03-30 12:53 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-27 9:40 [PATCH v8 00/24] Add vfio_device cdev for iommufd support Yi Liu
2023-03-27 9:40 ` [PATCH v8 01/24] vfio: Allocate per device file structure Yi Liu
2023-03-27 9:40 ` [PATCH v8 02/24] vfio: Refine vfio file kAPIs for KVM Yi Liu
2023-03-27 9:40 ` [PATCH v8 03/24] vfio: Remove vfio_file_is_group() Yi Liu
2023-03-30 23:50 ` Jason Gunthorpe
2023-03-27 9:40 ` [PATCH v8 04/24] vfio: Accept vfio device file in the KVM facing kAPI Yi Liu
2023-03-27 9:40 ` [PATCH v8 05/24] kvm/vfio: Rename kvm_vfio_group to prepare for accepting vfio device fd Yi Liu
2023-03-27 9:40 ` [PATCH v8 06/24] kvm/vfio: Accept vfio device file from userspace Yi Liu
2023-03-27 9:40 ` [PATCH v8 07/24] vfio: Pass struct vfio_device_file * to vfio_device_open/close() Yi Liu
2023-03-27 9:40 ` [PATCH v8 08/24] vfio: Block device access via device fd until device is opened Yi Liu
2023-03-28 21:33 ` Alex Williamson
2023-03-29 2:23 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 09/24] vfio: Add cdev_device_open_cnt to vfio_group Yi Liu
2023-03-27 9:40 ` [PATCH v8 10/24] vfio: Make vfio_device_open() single open for device cdev path Yi Liu
2023-03-30 23:52 ` Jason Gunthorpe
2023-03-27 9:40 ` [PATCH v8 11/24] vfio: Make vfio_device_first_open() to accept NULL iommufd for noiommu Yi Liu
2023-03-30 23:56 ` Jason Gunthorpe
2023-03-27 9:40 ` [PATCH v8 12/24] vfio-iommufd: Move noiommu support out of vfio_iommufd_bind() Yi Liu
2023-03-27 9:40 ` [PATCH v8 13/24] vfio-iommufd: Split bind/attach into two steps Yi Liu
2023-03-27 9:40 ` [PATCH v8 14/24] vfio: Record devid in vfio_device_file Yi Liu
2023-03-27 9:40 ` [PATCH v8 15/24] vfio-iommufd: Add detach_ioas support for physical VFIO devices Yi Liu
2023-03-27 9:40 ` [PATCH v8 16/24] iommufd/device: Add iommufd_access_detach() API Yi Liu
2023-03-28 2:23 ` Jon Pan-Doh
2023-03-28 15:54 ` Nicolin Chen
2023-03-29 2:24 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 17/24] vfio-iommufd: Add detach_ioas support for emulated VFIO devices Yi Liu
2023-03-27 9:40 ` [PATCH v8 18/24] vfio: Determine noiommu in vfio_device registration Yi Liu
2023-03-28 6:36 ` Tian, Kevin
2023-03-27 9:40 ` [PATCH v8 19/24] vfio: Name noiommu vfio_device with "noiommu-" prefix Yi Liu
2023-03-28 6:37 ` Tian, Kevin
2023-03-27 9:40 ` [PATCH v8 20/24] vfio: Add cdev for vfio_device Yi Liu
2023-03-29 19:57 ` Alex Williamson
2023-03-30 5:35 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 21/24] vfio: Add VFIO_DEVICE_BIND_IOMMUFD Yi Liu
2023-03-29 21:00 ` Alex Williamson
2023-03-29 23:22 ` Jason Gunthorpe
2023-03-30 12:52 ` Liu, Yi L [this message]
2023-03-30 12:59 ` Jason Gunthorpe
2023-03-30 7:09 ` Liu, Yi L
2023-03-30 11:52 ` Jason Gunthorpe
2023-03-30 12:53 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 22/24] vfio: Add VFIO_DEVICE_AT[DE]TACH_IOMMUFD_PT Yi Liu
2023-03-29 21:19 ` Alex Williamson
2023-03-30 13:02 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 23/24] vfio: Compile group optionally Yi Liu
2023-03-29 21:51 ` Alex Williamson
2023-03-30 13:06 ` Liu, Yi L
2023-03-27 9:40 ` [PATCH v8 24/24] docs: vfio: Add vfio device cdev description Yi Liu
2023-03-29 22:47 ` Alex Williamson
2023-03-29 22:57 ` Alex Williamson
2023-03-30 13:11 ` Liu, Yi L
2023-03-27 17:48 ` [PATCH v8 00/24] Add vfio_device cdev for iommufd support Nicolin Chen
2023-03-31 3:10 ` Jiang, Yanting
2023-03-31 5:01 ` Jiang, Yanting
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