From: "Liu, Yi L" <yi.l.liu@intel.com>
To: Alex Williamson <alex.williamson@redhat.com>,
Jason Gunthorpe <jgg@nvidia.com>
Cc: "mjrosato@linux.ibm.com" <mjrosato@linux.ibm.com>,
"jasowang@redhat.com" <jasowang@redhat.com>,
"Hao, Xudong" <xudong.hao@intel.com>,
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Subject: Re: [Intel-gfx] [PATCH v3 12/12] vfio/pci: Report dev_id in VFIO_DEVICE_GET_PCI_HOT_RESET_INFO
Date: Thu, 20 Apr 2023 12:10:20 +0000 [thread overview]
Message-ID: <DS0PR11MB7529C11E11F187D7BD88C18AC3639@DS0PR11MB7529.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20230418123920.5d92f402.alex.williamson@redhat.com>
> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Wednesday, April 19, 2023 2:39 AM
>
> On Tue, 18 Apr 2023 09:57:32 -0300
> Jason Gunthorpe <jgg@nvidia.com> wrote:
>
> > On Mon, Apr 17, 2023 at 02:06:42PM -0600, Alex Williamson wrote:
> > > On Mon, 17 Apr 2023 16:31:56 -0300
> > > Jason Gunthorpe <jgg@nvidia.com> wrote:
> > >
> > > > On Mon, Apr 17, 2023 at 01:01:40PM -0600, Alex Williamson wrote:
> > > > > Yes, it's not trivial, but Jason is now proposing that we consider
> > > > > mixing groups, cdevs, and multiple iommufd_ctxs as invalid. I think
> > > > > this means that regardless of which device calls INFO, there's only one
> > > > > answer (assuming same set of devices opened, all cdev, all within same
> > > > > iommufd_ctx). Based on what I explained about my understanding of INFO2
> > > > > and Jason agreed to, I think the output would be:
> > > > >
> > > > > flags: NOT_RESETABLE | DEV_ID
> > > > > {
> > > > > { valid devA-id, devA-BDF },
> > > > > { valid devC-id, devC-BDF },
> > > > > { valid devD-id, devD-BDF },
> > > > > { invalid dev-id, devE-BDF },
> > > > > }
> > > > >
> > > > > Here devB gets dropped because the kernel understands that devB is
> > > > > unopened, affected, and owned. It's therefore not a blocker for
> > > > > hot-reset.
> > > >
> > > > I don't think we want to drop anything because it makes the API
> > > > ill suited for the debugging purpose.
> > > >
> > > > devb should be returned with an invalid dev_id if I understand your
> > > > example. Maybe it should return with -1 as the dev_id instead of 0, to
> > > > make the debugging a bit better.
> > > >
> > > > Userspace should look at only NOT_RESETTABLE to determine if it
> > > > proceeds or not, and it should use the valid dev_id list to iterate
> > > > over the devices it has open to do the config stuff.
> > >
> > > If an affected device is owned, not opened, and not interfering with
> > > the reset, what is it adding to the API to report it for debugging
> > > purposes?
> >
> > It lets it print the entire group of devices, this is the only way
> > something can learn the actual list of all BDFs affected.
>
> If we do so, userspace must be able to differentiate which devices are
> blocking, which necessitates at least a bi-modal invalid dev-id.
>
> > dev_id can just return 0, we don't need a complex bitmap. Userspace
> > looks at the flag, if !NOT_RESETABLE then it ignores dev_id=0.
>
> I'm having trouble with a succinct definition of dev-id == 0, is it "A
> device affected by the hot-reset reset, which does not directly
> contribute to the availability of the hot-reset, ex. an unopened device
> within the same IOMMU group as an opened device (ie. this is not the
> device responsible if hot-reset is unavailable).
Hide this device in the list looks fine to me. But the calling user should
not do any new device open before finishing hot-reset. Otherwise, user may
miss a device that needs to do pre/post reset. I think this requirement is
acceptable. Is it?
> Whereas dev-id < 0
> (== -1) is an affected device which prevents hot-reset, ex. an un-owned
> device, device configured within a different iommufd_ctx, or device
> opened outside of the vfio cdev API." Is that about right? Thanks,
Do you mean to have separate err-code for the three possibilities? As
the devid is generated by iommufd and it is u32. I'm not sure if we can
have such err-code definition without reserving some ids in iommufd.
Regards,
Yi Liu
next prev parent reply other threads:[~2023-04-20 12:10 UTC|newest]
Thread overview: 145+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-01 14:44 [Intel-gfx] [PATCH v3 00/12] Introduce new methods for verifying ownership in vfio PCI hot reset Yi Liu
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 01/12] vfio/pci: Update comment around group_fd get in vfio_pci_ioctl_pci_hot_reset() Yi Liu
2023-04-04 13:59 ` Eric Auger
2023-04-04 14:37 ` Liu, Yi L
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 02/12] vfio/pci: Only check ownership of opened devices in hot reset Yi Liu
2023-04-04 13:59 ` Eric Auger
2023-04-04 14:37 ` Liu, Yi L
2023-04-04 15:18 ` Eric Auger
2023-04-04 15:29 ` Liu, Yi L
2023-04-04 15:59 ` Eric Auger
2023-04-05 11:41 ` Jason Gunthorpe
2023-04-05 15:14 ` Eric Auger
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 03/12] vfio/pci: Move the existing hot reset logic to be a helper Yi Liu
2023-04-04 13:59 ` Eric Auger
2023-04-04 14:24 ` Liu, Yi L
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 04/12] vfio-iommufd: Add helper to retrieve iommufd_ctx and devid for vfio_device Yi Liu
2023-04-04 15:28 ` Eric Auger
2023-04-04 21:48 ` Alex Williamson
2023-04-21 7:11 ` Liu, Yi L
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 05/12] vfio/pci: Allow passing zero-length fd array in VFIO_DEVICE_PCI_HOT_RESET Yi Liu
2023-04-04 16:54 ` Eric Auger
2023-04-04 20:18 ` Alex Williamson
2023-04-05 7:55 ` Liu, Yi L
2023-04-05 8:01 ` Liu, Yi L
2023-04-05 15:36 ` Alex Williamson
2023-04-05 16:46 ` Jason Gunthorpe
2023-04-05 8:02 ` Eric Auger
2023-04-05 8:09 ` Liu, Yi L
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 06/12] vfio: Refine vfio file kAPIs for vfio PCI hot reset Yi Liu
2023-04-05 8:27 ` Eric Auger
2023-04-05 9:23 ` Liu, Yi L
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 07/12] vfio: Accpet device file from vfio PCI hot reset path Yi Liu
2023-04-04 20:31 ` Alex Williamson
2023-04-05 8:07 ` Eric Auger
2023-04-05 8:10 ` Liu, Yi L
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 08/12] vfio/pci: Renaming for accepting device fd in " Yi Liu
2023-04-04 21:23 ` Alex Williamson
2023-04-05 9:32 ` Eric Auger
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 09/12] vfio/pci: Accept device fd in VFIO_DEVICE_PCI_HOT_RESET ioctl Yi Liu
2023-04-05 9:36 ` Eric Auger
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 10/12] vfio: Mark cdev usage in vfio_device Yi Liu
2023-04-05 11:48 ` Eric Auger
2023-04-21 7:06 ` Liu, Yi L
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 11/12] iommufd: Define IOMMUFD_INVALID_ID in uapi Yi Liu
2023-04-04 21:00 ` Alex Williamson
2023-04-05 9:31 ` Liu, Yi L
2023-04-05 15:13 ` Alex Williamson
2023-04-05 15:17 ` Liu, Yi L
2023-04-05 11:46 ` Eric Auger
2023-04-01 14:44 ` [Intel-gfx] [PATCH v3 12/12] vfio/pci: Report dev_id in VFIO_DEVICE_GET_PCI_HOT_RESET_INFO Yi Liu
2023-04-03 9:25 ` Liu, Yi L
2023-04-03 15:01 ` Alex Williamson
2023-04-03 15:22 ` Liu, Yi L
2023-04-03 15:32 ` Alex Williamson
2023-04-03 16:12 ` Jason Gunthorpe
2023-04-07 10:09 ` Liu, Yi L
2023-04-07 12:03 ` Alex Williamson
2023-04-07 13:24 ` Liu, Yi L
2023-04-07 13:51 ` Alex Williamson
2023-04-07 14:04 ` Liu, Yi L
2023-04-07 15:14 ` Alex Williamson
2023-04-07 15:47 ` Liu, Yi L
2023-04-07 21:07 ` Alex Williamson
2023-04-08 5:07 ` Liu, Yi L
2023-04-08 14:20 ` Alex Williamson
2023-04-09 11:58 ` Yi Liu
2023-04-09 13:29 ` Alex Williamson
2023-04-10 8:48 ` Liu, Yi L
2023-04-10 14:41 ` Alex Williamson
2023-04-10 15:18 ` Liu, Yi L
2023-04-10 15:23 ` Alex Williamson
2023-04-11 13:34 ` Jason Gunthorpe
2023-04-11 13:33 ` Jason Gunthorpe
2023-04-11 6:16 ` Liu, Yi L
2023-04-04 22:20 ` Alex Williamson
2023-04-05 12:19 ` Eric Auger
2023-04-05 14:04 ` Liu, Yi L
2023-04-05 16:25 ` Alex Williamson
2023-04-05 16:37 ` Jason Gunthorpe
2023-04-05 16:52 ` Alex Williamson
2023-04-05 17:23 ` Jason Gunthorpe
2023-04-05 18:56 ` Alex Williamson
2023-04-05 19:18 ` Alex Williamson
2023-04-05 19:21 ` Jason Gunthorpe
2023-04-05 19:49 ` Alex Williamson
2023-04-05 23:22 ` Jason Gunthorpe
2023-04-06 10:02 ` Liu, Yi L
2023-04-06 17:53 ` Alex Williamson
2023-04-07 10:09 ` Liu, Yi L
2023-04-11 13:24 ` Jason Gunthorpe
2023-04-11 15:54 ` Alex Williamson
2023-04-11 17:11 ` Alex Williamson
2023-04-11 18:40 ` Jason Gunthorpe
2023-04-11 21:58 ` Alex Williamson
2023-04-12 0:01 ` Jason Gunthorpe
2023-04-12 7:27 ` Tian, Kevin
2023-04-12 15:05 ` Jason Gunthorpe
2023-04-12 17:01 ` Alex Williamson
2023-04-13 2:57 ` Tian, Kevin
2023-04-12 10:09 ` Liu, Yi L
2023-04-12 16:54 ` Alex Williamson
2023-04-12 16:50 ` Alex Williamson
2023-04-12 20:06 ` Jason Gunthorpe
2023-04-13 8:25 ` Tian, Kevin
2023-04-13 11:50 ` Jason Gunthorpe
2023-04-13 14:35 ` Liu, Yi L
2023-04-13 14:41 ` Jason Gunthorpe
2023-04-13 18:07 ` Alex Williamson
2023-04-14 9:11 ` Tian, Kevin
2023-04-14 11:38 ` Liu, Yi L
2023-04-14 17:10 ` Alex Williamson
2023-04-17 4:20 ` Liu, Yi L
2023-04-17 19:01 ` Alex Williamson
2023-04-17 19:31 ` Jason Gunthorpe
2023-04-17 20:06 ` Alex Williamson
2023-04-18 3:24 ` Tian, Kevin
2023-04-18 4:10 ` Alex Williamson
2023-04-18 5:02 ` Tian, Kevin
2023-04-18 12:59 ` Jason Gunthorpe
2023-04-18 16:44 ` Alex Williamson
2023-04-18 10:34 ` Liu, Yi L
2023-04-18 16:49 ` Alex Williamson
2023-04-18 12:57 ` Jason Gunthorpe
2023-04-18 18:39 ` Alex Williamson
2023-04-20 12:10 ` Liu, Yi L [this message]
2023-04-20 14:08 ` Alex Williamson
2023-04-21 22:35 ` Jason Gunthorpe
2023-04-23 14:46 ` Liu, Yi L
2023-04-26 7:22 ` Liu, Yi L
2023-04-26 13:20 ` Alex Williamson
2023-04-26 15:08 ` Liu, Yi L
2023-04-14 16:34 ` Alex Williamson
2023-04-17 13:39 ` Jason Gunthorpe
2023-04-18 1:28 ` Tian, Kevin
2023-04-18 10:23 ` Liu, Yi L
2023-04-18 13:02 ` Jason Gunthorpe
2023-04-23 10:28 ` Liu, Yi L
2023-04-24 17:38 ` Jason Gunthorpe
2023-04-17 14:05 ` Jason Gunthorpe
2023-04-12 7:14 ` Tian, Kevin
2023-04-06 6:34 ` Liu, Yi L
2023-04-06 17:07 ` Alex Williamson
2023-04-05 17:58 ` Eric Auger
2023-04-06 5:31 ` Liu, Yi L
2023-04-01 14:47 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for Introduce new methods for verifying ownership in vfio PCI hot reset (rev4) Patchwork
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