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From: Max Gurtovoy <mgurtovoy@nvidia.com>
To: Alex Williamson <alex.williamson@redhat.com>,
	Jason Gunthorpe <jgg@nvidia.com>
Cc: <cohuck@redhat.com>, <kvm@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <aviadye@nvidia.com>,
	<oren@nvidia.com>, <shahafs@nvidia.com>, <parav@nvidia.com>,
	<artemp@nvidia.com>, <kwankhede@nvidia.com>, <ACurrid@nvidia.com>,
	<cjia@nvidia.com>, <yishaih@nvidia.com>, <kevin.tian@intel.com>,
	<hch@infradead.org>, <targupta@nvidia.com>,
	<shameerali.kolothum.thodi@huawei.com>, <liulongfang@huawei.com>,
	<yan.y.zhao@intel.com>
Subject: Re: [PATCH 09/11] PCI: add matching checks for driver_override binding
Date: Sun, 13 Jun 2021 11:19:46 +0300	[thread overview]
Message-ID: <117a5e68-d16e-c146-6d37-fcbfe49cb4f8@nvidia.com> (raw)
In-Reply-To: <20210608192711.4956cda2.alex.williamson@redhat.com>


On 6/9/2021 4:27 AM, Alex Williamson wrote:
> On Tue, 8 Jun 2021 19:45:17 -0300
> Jason Gunthorpe <jgg@nvidia.com> wrote:
>
>> On Tue, Jun 08, 2021 at 03:26:43PM -0600, Alex Williamson wrote:
>>>> drivers that specifically opt into this feature and the driver now has
>>>> the opportunity to provide a proper match table that indicates what HW
>>>> it can properly support. vfio-pci continues to support everything.
>>> In doing so, this also breaks the new_id method for vfio-pci.
>> Does it? How? The driver_override flag is per match entry not for the
>> entire device so new_id added things will work the same as before as
>> their new match entry's flags will be zero.
> Hmm, that might have been a testing issue; combining driverctl with
> manual new_id testing might have left a driver_override in place.
>   
>>> Sorry, with so many userspace regressions, crippling the
>>> driver_override interface with an assumption of such a narrow focus,
>>> creating a vfio specific match flag, I don't see where this can go.
>>> Thanks,
>> On the other hand it overcomes all the objections from the last go
>> round: how userspace figures out which driver to use with
>> driver_override and integrating the universal driver into the scheme.
>>
>> pci_stub could be delt with by marking it for driver_override like
>> vfio_pci.
> By marking it a "vfio driver override"? :-\
>
>> But driverctl as a general tool working with any module is not really
>> addressable.
>>
>> Is the only issue the blocking of the arbitary binding? That is not a
>> critical peice of this, IIRC
> We can't break userspace, which means new_id and driver_override need
> to work as they do now.  There are scads of driver binding scripts in
> the wild, for vfio-pci and other drivers.  We can't assume such a
> narrow scope.  Thanks,

what about the following code ?

@@ -152,12 +152,28 @@ static const struct pci_device_id 
*pci_match_device(struct pci_driver *drv,
         }
         spin_unlock(&drv->dynids.lock);

-       if (!found_id)
-               found_id = pci_match_id(drv->id_table, dev);
+       if (found_id)
+               return found_id;

-       /* driver_override will always match, send a dummy id */
-       if (!found_id && dev->driver_override)
+       found_id = pci_match_id(drv->id_table, dev);
+       if (found_id) {
+               /*
+                * if we found id in the static table, we must fulfill the
+                * matching flags (i.e. if PCI_ID_F_DRIVER_OVERRIDE flag is
+                * set, driver_override should be provided).
+                */
+               bool is_driver_override =
+                       (found_id->flags & PCI_ID_F_DRIVER_OVERRIDE) != 0;
+               if ((is_driver_override && !dev->driver_override) ||
+                   (dev->driver_override && !is_driver_override))
+                       return NULL;
+       } else if (dev->driver_override) {
+               /*
+                * if we didn't find suitable id in the static table,
+                * driver_override will still , send a dummy id
+                */
                 found_id = &pci_device_id_any;
+       }

         return found_id;
  }


dynamic ids (new_id) works as before.

Old driver_override works as before.

For "new" driver_override we must fulfill the new rules.

>
> Alex
>

  parent reply	other threads:[~2021-06-13  8:20 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-03 16:07 [RFC PATCH v4 00/11] Introduce vfio-pci-core subsystem Max Gurtovoy
2021-06-03 16:07 ` [PATCH 01/11] vfio-pci: rename vfio_pci.c to vfio_pci_core.c Max Gurtovoy
2021-06-03 16:08 ` [PATCH 02/11] vfio-pci: rename vfio_pci_private.h to vfio_pci_core.h Max Gurtovoy
2021-06-03 16:08 ` [PATCH 03/11] vfio-pci: rename vfio_pci_device to vfio_pci_core_device Max Gurtovoy
2021-06-03 16:08 ` [PATCH 04/11] vfio-pci: rename ops functions to fit core namings Max Gurtovoy
2021-06-03 16:08 ` [PATCH 05/11] vfio-pci: include vfio header in vfio_pci_core.h Max Gurtovoy
2021-06-03 16:08 ` [PATCH 06/11] vfio-pci: introduce vfio_pci.c Max Gurtovoy
2021-06-03 16:08 ` [PATCH 07/11] vfio-pci: move igd initialization to vfio_pci.c Max Gurtovoy
2021-06-03 16:08 ` [PATCH 08/11] PCI: add flags field to pci_device_id structure Max Gurtovoy
2021-06-03 16:08 ` [PATCH 09/11] PCI: add matching checks for driver_override binding Max Gurtovoy
2021-06-08 21:26   ` Alex Williamson
2021-06-08 22:45     ` Jason Gunthorpe
2021-06-09  1:27       ` Alex Williamson
2021-06-09  9:26         ` Max Gurtovoy
2021-06-13  8:19         ` Max Gurtovoy [this message]
2021-06-14  5:40           ` Christoph Hellwig
2021-06-14  8:18             ` Max Gurtovoy
2021-06-14 15:27               ` Christoph Hellwig
2021-06-14 16:01                 ` Jason Gunthorpe
2021-06-14 16:15                   ` Christoph Hellwig
2021-06-14 16:33                     ` Jason Gunthorpe
2021-06-14 18:42           ` Alex Williamson
2021-06-14 23:12             ` Max Gurtovoy
2021-06-15 15:00               ` Alex Williamson
2021-06-15 15:04                 ` Jason Gunthorpe
2021-06-15 16:20                   ` Alex Williamson
2021-06-15 20:42                     ` Jason Gunthorpe
2021-06-15 21:59                       ` Alex Williamson
2021-06-15 23:00                         ` Jason Gunthorpe
2021-06-15 23:22                           ` Alex Williamson
2021-06-15 23:32                             ` Jason Gunthorpe
2021-06-16  0:22                               ` Alex Williamson
2021-06-16  0:34                                 ` Jason Gunthorpe
2021-06-16 23:28                                   ` Max Gurtovoy
2021-06-16 23:33                                     ` Jason Gunthorpe
2021-06-16 23:42                                       ` Max Gurtovoy
2021-06-16 23:44                                         ` Jason Gunthorpe
2021-06-16 23:51                                           ` Max Gurtovoy
2021-06-16 23:56                                             ` Jason Gunthorpe
2021-06-20 14:46                                               ` Max Gurtovoy
2021-06-03 16:08 ` [PATCH 10/11] vfio-pci: introduce vfio_pci_core subsystem driver Max Gurtovoy
2021-06-08 21:26   ` Alex Williamson
2021-06-09  9:29     ` Max Gurtovoy
2021-06-03 16:08 ` [PATCH 11/11] mlx5-vfio-pci: add new vfio_pci driver for mlx5 devices Max Gurtovoy
2021-07-30  7:53 ` [RFC PATCH v4 00/11] Introduce vfio-pci-core subsystem Shameerali Kolothum Thodi
2021-07-30 11:55   ` Jason Gunthorpe

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