From: Max Gurtovoy <mgurtovoy@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>,
Alex Williamson <alex.williamson@redhat.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: Thu, 17 Jun 2021 02:28:36 +0300 [thread overview]
Message-ID: <cd95b92c-a23b-03a7-1dd3-9554b9d22955@nvidia.com> (raw)
In-Reply-To: <20210616003417.GH1002214@nvidia.com>
On 6/16/2021 3:34 AM, Jason Gunthorpe wrote:
> On Tue, Jun 15, 2021 at 06:22:45PM -0600, Alex Williamson wrote:
>> On Tue, 15 Jun 2021 20:32:57 -0300
>> Jason Gunthorpe <jgg@nvidia.com> wrote:
>>
>>> On Tue, Jun 15, 2021 at 05:22:42PM -0600, Alex Williamson wrote:
>>>
>>>>>> b) alone is a functional, runtime difference.
>>>>> I would state b) differently:
>>>>>
>>>>> b) Ignore the driver-override-only match entries in the ID table.
>>>> No, pci_match_device() returns NULL if a match is found that is marked
>>>> driver-override-only and a driver_override is not specified. That's
>>>> the same as no match at all. We don't then go on to search past that
>>>> match in the table, we fail to bind the driver. That's effectively an
>>>> anti-match when there's no driver_override on the device.
>>> anti-match isn't the intention. The deployment will have match tables
>>> where all entires are either flags=0 or are driver-override-only.
>> I'd expect pci-pf-stub to have one of each, an any-id with
>> override-only flag and the one device ID currently in the table with
>> no flag.
> Oh Hum. Actually I think this shows the anti-match behavior is
> actually a bug.. :(
>
> For something like pci_pf_stub_whitelist, if we add a
> driver_override-only using the PCI any id then it effectively disables
> new_id completely because the match search will alway find the
> driver_override match first and stop searching. There is no chance to
> see things new_id adds.
Actually the dynamic table is the first table the driver search. So
new_id works exactly the same AFAIU.
But you're right for static mixed table (I assumed that this will never
happen I guess).
If we put the any_id_override id before the non_override AMAZON device
entry in the pci-pf-stub we'll fail with the matching to the AMAZON device.
What about the bellow untested addition (also remove condition c):
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 296de7bc9dc9..2d46f6cd96f7 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -136,7 +136,7 @@ static const struct pci_device_id
*pci_match_device(struct pci_driver *drv,
struct pci_dev *dev)
{
struct pci_dynid *dynid;
- const struct pci_device_id *found_id = NULL;
+ const struct pci_device_id *found_id = NULL, *ids;
/* When driver_override is set, only bind to the matching driver */
if (dev->driver_override && strcmp(dev->driver_override,
drv->name))
@@ -155,8 +155,8 @@ static const struct pci_device_id
*pci_match_device(struct pci_driver *drv,
if (found_id)
return found_id;
- found_id = pci_match_id(drv->id_table, dev);
- if (found_id) {
+ ids = drv->id_table;
+ while ((found_id = pci_match_id(ids, dev))) {
/*
* if we found id in the static table, we must fulfill the
* matching flags (i.e. if PCI_ID_F_DRIVER_OVERRIDE flag is
@@ -164,17 +164,19 @@ static const struct pci_device_id
*pci_match_device(struct pci_driver *drv,
*/
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;
+ if (is_driver_override && !dev->driver_override)
+ ids = found_id++; /* continue searching */
+ else
+ break;
}
+ /*
+ * if no static match, driver_override will always match, send a
dummy
+ * id.
+ */
+ if (!found_id && dev->driver_override)
+ found_id = &pci_device_id_any;
+
return found_id;
}
diff --git a/drivers/pci/pci-pf-stub.c b/drivers/pci/pci-pf-stub.c
index 45855a5e9fca..49544ba9a7af 100644
--- a/drivers/pci/pci-pf-stub.c
+++ b/drivers/pci/pci-pf-stub.c
@@ -19,6 +19,7 @@
*/
static const struct pci_device_id pci_pf_stub_whitelist[] = {
{ PCI_VDEVICE(AMAZON, 0x0053) },
+ { PCI_DEVICE_FLAGS(PCI_ANY_ID, PCI_ANY_ID,
PCI_ID_F_STUB_DRIVER_OVERRIDE) }, /* match all by default (override) */
/* required last entry */
{ 0 }
};
>
> We have to fix this patch so flags isn't an anti-match to make it work
> without user regression.
>
> Jason
next prev parent reply other threads:[~2021-06-16 23:28 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
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 [this message]
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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