From: Jason Gunthorpe <jgg@nvidia.com>
To: Yi Liu <yi.l.liu@intel.com>
Cc: alex.williamson@redhat.com, kevin.tian@intel.com,
cohuck@redhat.com, eric.auger@redhat.com, nicolinc@nvidia.com,
kvm@vger.kernel.org, mjrosato@linux.ibm.com,
chao.p.peng@linux.intel.com, yi.y.sun@linux.intel.com,
peterx@redhat.com, jasowang@redhat.com
Subject: Re: [RFC 05/12] kvm/vfio: Accept vfio device file from userspace
Date: Fri, 6 Jan 2023 10:32:43 -0400 [thread overview]
Message-ID: <Y7gxC/am09Cr885J@nvidia.com> (raw)
In-Reply-To: <20221219084718.9342-6-yi.l.liu@intel.com>
On Mon, Dec 19, 2022 at 12:47:11AM -0800, Yi Liu wrote:
> This defines KVM_DEV_VFIO_FILE* and make alias with KVM_DEV_VFIO_GROUP*.
> Old userspace uses KVM_DEV_VFIO_GROUP* works as well.
Do we have a circular refcount problem with this plan?
The kvm will hold a ref on the vfio device struct file
Once the vfio device struct file reaches open_device we will hold a
ref on the kvm
At this point if both kvm and vfio device FDs are closed will the
kernel clean it up or does it leak because they both ref each other?
Please test to confirm..
Jason
next prev parent reply other threads:[~2023-01-06 14:33 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-19 8:47 [RFC 00/12] Add vfio_device cdev for iommufd support Yi Liu
2022-12-19 8:47 ` [RFC 01/12] vfio: Allocate per device file structure Yi Liu
2022-12-21 3:57 ` Tian, Kevin
2022-12-21 6:46 ` Yi Liu
2022-12-19 8:47 ` [RFC 02/12] vfio: Refine vfio file kAPIs Yi Liu
2022-12-19 8:47 ` [RFC 03/12] vfio: Accept vfio device file in the driver facing kAPI Yi Liu
2022-12-21 4:07 ` Tian, Kevin
2022-12-21 7:02 ` Yi Liu
2023-01-04 18:25 ` Jason Gunthorpe
2023-01-09 4:13 ` Tian, Kevin
2022-12-19 8:47 ` [RFC 04/12] kvm/vfio: Rename kvm_vfio_group to prepare for accepting vfio device fd Yi Liu
2022-12-19 8:47 ` [RFC 05/12] kvm/vfio: Accept vfio device file from userspace Yi Liu
2023-01-06 14:32 ` Jason Gunthorpe [this message]
2023-01-06 14:46 ` Yi Liu
2023-01-06 14:55 ` Jason Gunthorpe
2023-01-06 15:04 ` Yi Liu
2023-01-06 16:08 ` Jason Gunthorpe
2023-01-09 4:17 ` Tian, Kevin
2023-01-09 4:26 ` Yi Liu
2022-12-19 8:47 ` [RFC 06/12] vfio: Pass struct vfio_device_file * to vfio_device_open/close() Yi Liu
2022-12-21 4:10 ` Tian, Kevin
2022-12-21 7:04 ` Yi Liu
2022-12-19 8:47 ` [RFC 07/12] vfio: Block device access via device fd until device is opened Yi Liu
2022-12-21 4:18 ` Tian, Kevin
2023-01-04 20:47 ` Jason Gunthorpe
2022-12-19 8:47 ` [RFC 08/12] vfio: Add infrastructure for bind_iommufd and attach Yi Liu
2023-01-09 5:46 ` Tian, Kevin
2023-01-09 13:21 ` Jason Gunthorpe
2023-01-10 2:53 ` Tian, Kevin
2022-12-19 8:47 ` [RFC 09/12] vfio: Make vfio_device_open() exclusive between group path and device cdev path Yi Liu
2023-01-09 6:03 ` Tian, Kevin
2022-12-19 8:47 ` [RFC 10/12] vfio: Add cdev for vfio_device Yi Liu
2023-01-09 6:54 ` Tian, Kevin
2022-12-19 8:47 ` [RFC 11/12] vfio: Add ioctls for device cdev iommufd Yi Liu
2023-01-09 7:47 ` Tian, Kevin
2023-01-09 14:14 ` Jason Gunthorpe
2023-01-09 15:07 ` Yi Liu
2023-01-09 15:12 ` Jason Gunthorpe
2023-01-09 15:20 ` Yi Liu
2023-01-09 14:55 ` Yi Liu
2023-01-10 2:57 ` Tian, Kevin
2022-12-19 8:47 ` [RFC 12/12] vfio: Compile group optionally Yi Liu
2022-12-19 8:51 ` [RFC 00/12] Add vfio_device cdev for iommufd support Yi Liu
2023-01-04 15:23 ` Yi Liu
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