From: "Tian, Kevin" <kevin.tian@intel.com>
To: "Liu, Yi L" <yi.l.liu@intel.com>,
"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"jgg@nvidia.com" <jgg@nvidia.com>
Cc: "joro@8bytes.org" <joro@8bytes.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"eric.auger@redhat.com" <eric.auger@redhat.com>,
"nicolinc@nvidia.com" <nicolinc@nvidia.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"chao.p.peng@linux.intel.com" <chao.p.peng@linux.intel.com>,
"iommu@lists.linux.dev" <iommu@lists.linux.dev>,
"baolu.lu@linux.intel.com" <baolu.lu@linux.intel.com>,
"Duan, Zhenzhong" <zhenzhong.duan@intel.com>,
"Pan, Jacob jun" <jacob.jun.pan@intel.com>,
Matthew Wilcox <willy@infradead.org>
Subject: RE: [PATCH v2 2/4] vfio-iommufd: Support pasid [at|de]tach for physical VFIO devices
Date: Tue, 16 Apr 2024 09:47:44 +0000 [thread overview]
Message-ID: <BN9PR11MB5276D407CC14E0C9D8AE17998C082@BN9PR11MB5276.namprd11.prod.outlook.com> (raw)
In-Reply-To: <d0dc889b-003c-44cd-9f8a-a14d6b7009bc@intel.com>
> From: Liu, Yi L <yi.l.liu@intel.com>
> Sent: Tuesday, April 16, 2024 5:25 PM
>
> On 2024/4/16 17:01, Tian, Kevin wrote:
> >> From: Liu, Yi L <yi.l.liu@intel.com>
> >> Sent: Friday, April 12, 2024 4:21 PM
> >>
> >> +
> >> + rc = ida_get_lowest(&vdev->pasids, pasid, pasid);
> >> + if (rc == pasid)
> >> + return iommufd_device_pasid_replace(vdev-
> >>> iommufd_device,
> >> + pasid, pt_id);
> >> +
> >> + rc = iommufd_device_pasid_attach(vdev->iommufd_device, pasid,
> >> pt_id);
> >> + if (rc)
> >> + return rc;
> >> +
> >> + rc = ida_alloc_range(&vdev->pasids, pasid, pasid, GFP_KERNEL);
> >> + if (rc < 0) {
> >> + iommufd_device_pasid_detach(vdev->iommufd_device,
> >> pasid);
> >> + return rc;
> >> + }
> >
> > I'd do simple operation (ida_alloc_range()) first before doing attach.
> >
>
> But that means we rely on the ida_alloc_range() to return -ENOSPC to
> indicate the pasid is allocated, hence this attach is actually a
> replacement. This is easy to be broken if ida_alloc_range() returns
> -ENOSPC for other reasons in future.
>
ida_alloc_range() could fail for other reasons e.g. -ENOMEM.
in case I didn't make it clear I just meant to swap the order
between iommufd_device_pasid_attach() and ida_alloc_range().
replacement is still checked against ida_get_lowest().
next prev parent reply other threads:[~2024-04-16 9:47 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-12 8:21 [PATCH v2 0/4] vfio-pci support pasid attach/detach Yi Liu
2024-04-12 8:21 ` [PATCH v2 1/4] ida: Add ida_get_lowest() Yi Liu
2024-04-16 16:03 ` Alex Williamson
2024-04-18 7:02 ` Yi Liu
2024-04-18 16:23 ` Alex Williamson
2024-04-18 17:12 ` Jason Gunthorpe
2024-04-19 13:43 ` Yi Liu
2024-04-19 13:55 ` Alex Williamson
2024-04-19 14:00 ` Jason Gunthorpe
2024-04-23 7:19 ` Yi Liu
2024-04-19 13:40 ` Yi Liu
2024-04-12 8:21 ` [PATCH v2 2/4] vfio-iommufd: Support pasid [at|de]tach for physical VFIO devices Yi Liu
2024-04-16 9:01 ` Tian, Kevin
2024-04-16 9:24 ` Yi Liu
2024-04-16 9:47 ` Tian, Kevin [this message]
2024-04-18 7:04 ` Yi Liu
2024-04-23 12:43 ` Jason Gunthorpe
2024-04-24 0:33 ` Tian, Kevin
2024-04-24 4:48 ` Yi Liu
2024-04-12 8:21 ` [PATCH v2 3/4] vfio: Add VFIO_DEVICE_PASID_[AT|DE]TACH_IOMMUFD_PT Yi Liu
2024-04-16 9:13 ` Tian, Kevin
2024-04-16 9:36 ` Yi Liu
2024-04-23 12:45 ` Jason Gunthorpe
2024-04-12 8:21 ` [PATCH v2 4/4] vfio: Report PASID capability via VFIO_DEVICE_FEATURE ioctl Yi Liu
2024-04-16 9:40 ` Tian, Kevin
2024-04-16 17:57 ` Alex Williamson
2024-04-17 7:09 ` Tian, Kevin
2024-04-17 20:25 ` Alex Williamson
2024-04-18 0:21 ` Tian, Kevin
2024-04-18 8:23 ` Yi Liu
2024-04-18 16:34 ` Alex Williamson
2024-04-23 12:39 ` Jason Gunthorpe
2024-04-24 0:24 ` Tian, Kevin
2024-04-24 13:59 ` Jason Gunthorpe
2024-04-16 8:38 ` [PATCH v2 0/4] vfio-pci support pasid attach/detach Tian, Kevin
2024-04-16 17:50 ` Jason Gunthorpe
2024-04-17 7:16 ` Tian, Kevin
2024-04-17 12:20 ` Jason Gunthorpe
2024-04-17 23:02 ` Alex Williamson
2024-04-18 0:06 ` Tian, Kevin
2024-04-18 9:03 ` Yi Liu
2024-04-18 20:37 ` Alex Williamson
2024-04-19 5:52 ` Tian, Kevin
2024-04-19 16:35 ` Alex Williamson
2024-04-23 7:43 ` Tian, Kevin
2024-04-23 12:01 ` Jason Gunthorpe
2024-04-23 23:47 ` Tian, Kevin
2024-04-24 0:12 ` Jason Gunthorpe
2024-04-24 2:57 ` Tian, Kevin
2024-04-24 12:29 ` Baolu Lu
2024-04-24 14:04 ` Jason Gunthorpe
2024-04-24 5:19 ` Tian, Kevin
2024-04-24 14:15 ` Jason Gunthorpe
2024-04-24 18:38 ` Alex Williamson
2024-04-24 18:45 ` Jason Gunthorpe
2024-04-24 18:24 ` Alex Williamson
2024-04-24 18:36 ` Jason Gunthorpe
2024-04-24 20:13 ` Alex Williamson
2024-04-26 14:11 ` Jason Gunthorpe
2024-04-26 20:13 ` Alex Williamson
2024-04-28 6:19 ` Tian, Kevin
2024-04-29 7:43 ` Yi Liu
2024-04-29 17:15 ` Jason Gunthorpe
2024-04-29 17:44 ` Jason Gunthorpe
2024-04-27 5:05 ` Christoph Hellwig
2024-04-25 9:26 ` Yi Liu
2024-04-25 12:58 ` Alex Williamson
2024-04-26 9:01 ` Yi Liu
2024-04-19 13:59 ` Jason Gunthorpe
2024-04-23 7:58 ` Yi Liu
2024-04-23 12:05 ` Jason Gunthorpe
2024-04-19 13:34 ` Jason Gunthorpe
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