* [PATCH RFC] pci: fix device presence detection for VFs
@ 2022-10-10 17:12 Michael S. Tsirkin
2022-10-11 21:01 ` Michael S. Tsirkin
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2022-10-10 17:12 UTC (permalink / raw)
To: linux-kernel; +Cc: Bjorn Helgaas, linux-pci, virtualization
virtio uses the same driver for VFs and PFs. Accordingly,
pci_device_is_present is used to detect device presence. This function
isn't currently working properly for VFs since it attempts reading
device and vendor ID. Result is device marked broken incorrectly. As
VFs are present if and only if PF is present, just return the value for
that device.
Reported-by: gongwei <gongwei833x@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
Warning - compile tested only. gongwei could you help test and report
please?
drivers/pci/pci.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 95bc329e74c0..ba29b8e2f3c1 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -6462,6 +6462,9 @@ bool pci_device_is_present(struct pci_dev *pdev)
{
u32 v;
+ if (pdev->is_virtfn)
+ return pci_device_is_present(pdev->physfn);
+
if (pci_dev_is_disconnected(pdev))
return false;
return pci_bus_read_dev_vendor_id(pdev->bus, pdev->devfn, &v, 0);
--
MST
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH RFC] pci: fix device presence detection for VFs
2022-10-10 17:12 [PATCH RFC] pci: fix device presence detection for VFs Michael S. Tsirkin
@ 2022-10-11 21:01 ` Michael S. Tsirkin
2022-10-14 11:31 ` Wei Gong
2022-10-26 3:39 ` Wei Gong
2 siblings, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2022-10-11 21:01 UTC (permalink / raw)
To: linux-kernel; +Cc: Bjorn Helgaas, linux-pci, virtualization
On Mon, Oct 10, 2022 at 01:12:20PM -0400, Michael S. Tsirkin wrote:
> virtio uses the same driver for VFs and PFs. Accordingly,
> pci_device_is_present is used to detect device presence. This function
> isn't currently working properly for VFs since it attempts reading
> device and vendor ID. Result is device marked broken incorrectly. As
> VFs are present if and only if PF is present, just return the value for
> that device.
>
> Reported-by: gongwei <gongwei833x@gmail.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
>
> ---
>
> Warning - compile tested only. gongwei could you help test and report
> please?
Just got a report in private email that it was tested and works well.
Will repost as non-RFC now.
> drivers/pci/pci.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 95bc329e74c0..ba29b8e2f3c1 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -6462,6 +6462,9 @@ bool pci_device_is_present(struct pci_dev *pdev)
> {
> u32 v;
>
> + if (pdev->is_virtfn)
> + return pci_device_is_present(pdev->physfn);
> +
> if (pci_dev_is_disconnected(pdev))
> return false;
> return pci_bus_read_dev_vendor_id(pdev->bus, pdev->devfn, &v, 0);
> --
> MST
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH RFC] pci: fix device presence detection for VFs
2022-10-10 17:12 [PATCH RFC] pci: fix device presence detection for VFs Michael S. Tsirkin
2022-10-11 21:01 ` Michael S. Tsirkin
@ 2022-10-14 11:31 ` Wei Gong
2022-10-26 3:39 ` Wei Gong
2 siblings, 0 replies; 4+ messages in thread
From: Wei Gong @ 2022-10-14 11:31 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: linux-kernel, Bjorn Helgaas, linux-pci, virtualization
On Mon, Oct 10, 2022 at 01:12:20PM -0400, Michael S. Tsirkin wrote:
> virtio uses the same driver for VFs and PFs. Accordingly,
> pci_device_is_present is used to detect device presence. This function
> isn't currently working properly for VFs since it attempts reading
> device and vendor ID. Result is device marked broken incorrectly. As
> VFs are present if and only if PF is present, just return the value for
> that device.
>
> Reported-by: gongwei <gongwei833x@gmail.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Wei Gong <gongwei833x@gmail.com>
>
> ---
>
> Warning - compile tested only. gongwei could you help test and report
> please?
I have done the test and it works well
>
> drivers/pci/pci.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 95bc329e74c0..ba29b8e2f3c1 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -6462,6 +6462,9 @@ bool pci_device_is_present(struct pci_dev *pdev)
> {
> u32 v;
>
> + if (pdev->is_virtfn)
> + return pci_device_is_present(pdev->physfn);
> +
> if (pci_dev_is_disconnected(pdev))
> return false;
> return pci_bus_read_dev_vendor_id(pdev->bus, pdev->devfn, &v, 0);
> --
> MST
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH RFC] pci: fix device presence detection for VFs
2022-10-10 17:12 [PATCH RFC] pci: fix device presence detection for VFs Michael S. Tsirkin
2022-10-11 21:01 ` Michael S. Tsirkin
2022-10-14 11:31 ` Wei Gong
@ 2022-10-26 3:39 ` Wei Gong
2 siblings, 0 replies; 4+ messages in thread
From: Wei Gong @ 2022-10-26 3:39 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: linux-kernel, Bjorn Helgaas, linux-pci, virtualization
On Mon, Oct 10, 2022 at 01:12:20PM -0400, Michael S. Tsirkin wrote:
> virtio uses the same driver for VFs and PFs. Accordingly,
> pci_device_is_present is used to detect device presence. This function
> isn't currently working properly for VFs since it attempts reading
> device and vendor ID. Result is device marked broken incorrectly. As
> VFs are present if and only if PF is present, just return the value for
> that device.
>
> Reported-by: gongwei <gongwei833x@gmail.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Wei Gong <gongwei833x@gmail.com>
>
> ---
>
> Warning - compile tested only. gongwei could you help test and report
> please?
Tested and working well. Any plans for next steps?
>
> drivers/pci/pci.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 95bc329e74c0..ba29b8e2f3c1 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -6462,6 +6462,9 @@ bool pci_device_is_present(struct pci_dev *pdev)
> {
> u32 v;
>
> + if (pdev->is_virtfn)
> + return pci_device_is_present(pdev->physfn);
> +
> if (pci_dev_is_disconnected(pdev))
> return false;
> return pci_bus_read_dev_vendor_id(pdev->bus, pdev->devfn, &v, 0);
> --
> MST
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-10-26 3:39 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-10-10 17:12 [PATCH RFC] pci: fix device presence detection for VFs Michael S. Tsirkin
2022-10-11 21:01 ` Michael S. Tsirkin
2022-10-14 11:31 ` Wei Gong
2022-10-26 3:39 ` Wei Gong
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