From: Jason Gunthorpe <jgg@nvidia.com>
To: "Liu, Yi L" <yi.l.liu@intel.com>
Cc: "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
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Subject: Re: [PATCH v5 17/19] vfio: Add VFIO_DEVICE_AT[DE]TACH_IOMMUFD_PT
Date: Tue, 28 Feb 2023 10:38:17 -0400 [thread overview]
Message-ID: <Y/4R2SRFKoRFg4qK@nvidia.com> (raw)
In-Reply-To: <DS0PR11MB75293E34AB7C53F7ABFC0E36C3AC9@DS0PR11MB7529.namprd11.prod.outlook.com>
On Tue, Feb 28, 2023 at 02:01:36PM +0000, Liu, Yi L wrote:
> > From: Jason Gunthorpe <jgg@nvidia.com>
> > Sent: Tuesday, February 28, 2023 9:44 PM
> >
> > On Tue, Feb 28, 2023 at 01:36:24PM +0000, Liu, Yi L wrote:
> > > > From: Jason Gunthorpe <jgg@nvidia.com>
> > > > Sent: Tuesday, February 28, 2023 9:26 PM
> > > >
> > > > On Tue, Feb 28, 2023 at 01:22:50PM +0000, Liu, Yi L wrote:
> > > >
> > > > > > A null iommufd pointer and a bound df flag is sufficient to see that
> > > > > > it is compat mode.
> > > > >
> > > > > Hope df->is_cdev_device suits your expectation.:-) The code will look
> > > > > like below:
> > > >
> > > > Yes, this is better.. However I'd suggest 'uses_container' as it is
> > > > clearer what the special case is
> > >
> > > Surely doable. Need to add a helper like below:
> > >
> > > bool vfio_device_group_uses_container()
> > > {
> > > lockdep_assert_held(&device->group->group_lock);
> > > return device->group->container;
> > > }
> >
> > It should come from the df.
> >
> > If you have a df then by definition:
> > smp_load_acquire(..) == false - Not bound
> > df->device->iommufd_ctx != NULL - Using iommufd
> > df->group->containter != NULL - Using legacy container
> > all other cases - NO_IOMMU
> >
> > No locking required since all these cases after the smp_load_acquire
> > must be fixed for the lifetime of the df.
>
> Do you mean the df->access_granted (introduced in patch 07) or a new
> flag?
yes
> Following your suggestion, it seems a mandatory requirement to do the
> smp_load_acquire(..) == false check first, and then call into the vfio_device_open()
> which further calls vfio_device_first_open() to check the iommufd/
> legacy container/noiommu stuffs. Is it?
Figuring out if an open should happen or not is a different operation,
you already build exclusion between cdev/group so we don't need to
care about the open path.
> df->group->containter this may need a helper to avoid decoding group
> field. May be just store container in df?
At worst a flag, but a helper seems like a good idea anyhow, then it
can be compiled out
Jason
next prev parent reply other threads:[~2023-02-28 14:38 UTC|newest]
Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-27 11:11 [PATCH v5 00/19] Add vfio_device cdev for iommufd support Yi Liu
2023-02-27 11:11 ` [PATCH v5 01/19] vfio: Allocate per device file structure Yi Liu
2023-02-27 18:46 ` Jason Gunthorpe
2023-02-27 11:11 ` [PATCH v5 02/19] vfio: Refine vfio file kAPIs for KVM Yi Liu
2023-02-27 18:46 ` Jason Gunthorpe
2023-02-27 11:11 ` [PATCH v5 03/19] vfio: Accept vfio device file in the KVM facing kAPI Yi Liu
2023-02-27 18:46 ` Jason Gunthorpe
2023-02-27 11:11 ` [PATCH v5 04/19] kvm/vfio: Rename kvm_vfio_group to prepare for accepting vfio device fd Yi Liu
2023-02-27 18:47 ` Jason Gunthorpe
2023-02-27 11:11 ` [PATCH v5 05/19] kvm/vfio: Accept vfio device file from userspace Yi Liu
2023-02-27 18:47 ` Jason Gunthorpe
2023-02-27 11:11 ` [PATCH v5 06/19] vfio: Pass struct vfio_device_file * to vfio_device_open/close() Yi Liu
2023-02-27 18:47 ` Jason Gunthorpe
2023-02-27 11:11 ` [PATCH v5 07/19] vfio: Block device access via device fd until device is opened Yi Liu
2023-02-27 18:48 ` Jason Gunthorpe
2023-03-01 9:22 ` Liu, Yi L
2023-02-27 11:11 ` [PATCH v5 08/19] vfio/pci: Update comment around group_fd get in vfio_pci_ioctl_pci_hot_reset() Yi Liu
2023-02-27 18:48 ` Jason Gunthorpe
2023-02-27 11:11 ` [PATCH v5 09/19] vfio/pci: Allow passing zero-length fd array in VFIO_DEVICE_PCI_HOT_RESET Yi Liu
2023-02-27 18:22 ` Jason Gunthorpe
2023-02-28 2:31 ` Liu, Yi L
2023-03-02 6:07 ` Liu, Yi L
2023-03-02 9:55 ` Tian, Kevin
2023-03-02 12:35 ` Jason Gunthorpe
2023-03-02 14:20 ` Liu, Yi L
2023-03-03 6:36 ` Tian, Kevin
2023-03-03 16:55 ` Alex Williamson
2023-03-05 14:48 ` Liu, Yi L
2023-03-06 8:16 ` Tian, Kevin
2023-03-06 8:23 ` Tian, Kevin
2023-03-06 8:33 ` Liu, Yi L
2023-03-06 9:59 ` Liu, Yi L
2023-03-06 13:16 ` Jason Gunthorpe
2023-03-07 2:31 ` Tian, Kevin
2023-03-07 2:35 ` Liu, Yi L
2023-03-07 12:36 ` Jason Gunthorpe
2023-03-07 13:28 ` Liu, Yi L
2023-03-08 7:26 ` Tian, Kevin
2023-03-08 7:47 ` Liu, Yi L
2023-03-08 7:55 ` Tian, Kevin
2023-03-08 8:00 ` Liu, Yi L
2023-03-08 8:14 ` Tian, Kevin
2023-03-08 8:15 ` Liu, Yi L
2023-03-08 15:08 ` Jason Gunthorpe
2023-03-02 21:04 ` Alex Williamson
2023-02-27 11:11 ` [PATCH v5 10/19] vfio: Add infrastructure for bind_iommufd from userspace Yi Liu
2023-02-27 18:29 ` Jason Gunthorpe
2023-02-28 2:35 ` Liu, Yi L
2023-02-28 6:58 ` Liu, Yi L
2023-02-28 12:31 ` Jason Gunthorpe
2023-02-28 12:45 ` Liu, Yi L
2023-02-28 12:52 ` Jason Gunthorpe
2023-02-28 12:56 ` Liu, Yi L
2023-02-28 12:58 ` Jason Gunthorpe
2023-02-28 12:29 ` Jason Gunthorpe
2023-02-28 12:48 ` Liu, Yi L
2023-02-28 12:52 ` Jason Gunthorpe
2023-02-28 13:24 ` Liu, Yi L
2023-02-27 11:11 ` [PATCH v5 11/19] vfio-iommufd: Add detach_ioas support for physical VFIO devices Yi Liu
2023-02-27 18:44 ` Jason Gunthorpe
2023-02-28 2:57 ` Liu, Yi L
2023-02-28 12:33 ` Jason Gunthorpe
2023-02-28 12:43 ` Liu, Yi L
2023-02-27 11:11 ` [PATCH v5 12/19] vfio-iommufd: Add detach_ioas for emulated " Yi Liu
2023-02-27 18:45 ` Jason Gunthorpe
2023-02-27 11:11 ` [PATCH v5 13/19] vfio: Add cdev_device_open_cnt to vfio_group Yi Liu
2023-02-27 19:20 ` Jason Gunthorpe
2023-02-27 11:11 ` [PATCH v5 14/19] vfio: Make vfio_device_open() single open for device cdev path Yi Liu
2023-02-27 18:52 ` Jason Gunthorpe
2023-02-28 3:11 ` Liu, Yi L
2023-02-28 12:33 ` Jason Gunthorpe
2023-03-01 13:58 ` Liu, Yi L
2023-02-27 11:11 ` [PATCH v5 15/19] vfio: Add cdev for vfio_device Yi Liu
2023-02-27 18:55 ` Jason Gunthorpe
2023-02-28 3:47 ` Liu, Yi L
2023-02-27 19:06 ` Jason Gunthorpe
2023-02-28 3:59 ` Liu, Yi L
2023-02-27 11:11 ` [PATCH v5 16/19] vfio: Add VFIO_DEVICE_BIND_IOMMUFD Yi Liu
2023-02-27 19:19 ` Jason Gunthorpe
2023-02-28 4:08 ` Liu, Yi L
2023-03-01 9:19 ` Liu, Yi L
2023-03-01 17:46 ` Jason Gunthorpe
2023-03-02 4:09 ` Liu, Yi L
2023-03-03 6:57 ` Liu, Yi L
2023-03-03 7:23 ` Liu, Yi L
2023-03-07 6:38 ` Tian, Kevin
2023-03-07 12:37 ` Jason Gunthorpe
2023-03-07 13:03 ` Liu, Yi L
2023-03-08 7:17 ` Tian, Kevin
2023-03-10 2:39 ` Alexey Kardashevskiy
2023-03-10 5:49 ` Liu, Yi L
2023-02-27 11:11 ` [PATCH v5 17/19] vfio: Add VFIO_DEVICE_AT[DE]TACH_IOMMUFD_PT Yi Liu
2023-02-27 18:39 ` Jason Gunthorpe
2023-02-28 2:51 ` Liu, Yi L
2023-02-28 12:32 ` Jason Gunthorpe
2023-02-28 12:42 ` Liu, Yi L
2023-02-28 12:53 ` Jason Gunthorpe
2023-02-28 13:22 ` Liu, Yi L
2023-02-28 13:25 ` Jason Gunthorpe
2023-02-28 13:36 ` Liu, Yi L
2023-02-28 13:43 ` Jason Gunthorpe
2023-02-28 14:01 ` Liu, Yi L
2023-02-28 14:38 ` Jason Gunthorpe [this message]
2023-03-01 14:04 ` Liu, Yi L
2023-03-01 17:49 ` Jason Gunthorpe
2023-03-02 3:24 ` Liu, Yi L
2023-02-27 11:11 ` [PATCH v5 18/19] vfio: Compile group optionally Yi Liu
2023-02-27 19:20 ` Jason Gunthorpe
2023-02-28 3:14 ` Liu, Yi L
2023-02-28 6:00 ` Liu, Yi L
2023-02-28 12:36 ` Jason Gunthorpe
2023-03-01 13:59 ` Liu, Yi L
2023-02-27 11:11 ` [PATCH v5 19/19] docs: vfio: Add vfio device cdev description Yi Liu
2023-02-27 19:21 ` [PATCH v5 00/19] Add vfio_device cdev for iommufd support Jason Gunthorpe
2023-02-28 3:03 ` Liu, Yi L
2023-02-28 16:58 ` Xu, Terrence
2023-03-01 2:29 ` Nicolin Chen
2023-03-01 3:44 ` Liu, Yi L
2023-03-02 9:43 ` Shameerali Kolothum Thodi
2023-03-02 23:51 ` Nicolin Chen
2023-03-03 15:01 ` Shameerali Kolothum Thodi
2023-03-04 7:00 ` Nicolin Chen
2023-03-04 8:22 ` Liu, Yi L
2023-03-08 15:54 ` Shameerali Kolothum Thodi
2023-03-14 11:38 ` Shameerali Kolothum Thodi
2023-03-15 23:22 ` Nicolin Chen
2023-03-16 7:39 ` Liu, Yi L
2023-03-03 21:29 ` Matthew Rosato
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