[PATCH net-next] net: mana: Add handler for sriov configure

[PATCH net-next] net: mana: Add handler for sriov configure

[Haiyang Zhang]

From: Haiyang Zhang <haiyangz@microsoft.com>

Add callback function for the pci_driver, sriov_configure.

Also disable VF autoprobe when it runs as PF driver on bare metal,
since the hardware side may not have the VF ready immediately.

Export pci_vf_drivers_autoprobe() so the driver can toggle the VF
autoprobe flag.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 .../net/ethernet/microsoft/mana/gdma_main.c   | 20 +++++++++++++++++++
 drivers/pci/iov.c                             |  1 +
 2 files changed, 21 insertions(+)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index 3bc3fff55999..767f11d5b351 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -2094,6 +2094,11 @@ static int mana_gd_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	gc->numa_node = dev_to_node(&pdev->dev);
 	gc->is_pf = mana_is_pf(pdev->device);
+
+	/* Disable VF autoprobe on BM */
+	if (gc->is_pf)
+		pci_vf_drivers_autoprobe(pdev, false);
+
 	gc->bar0_va = bar0_va;
 	gc->dev = &pdev->dev;
 	xa_init(&gc->irq_contexts);
@@ -2262,6 +2267,20 @@ static void mana_gd_shutdown(struct pci_dev *pdev)
 	pci_disable_device(pdev);
 }
 
+static int mana_sriov_configure(struct pci_dev *pdev, int numvfs)
+{
+	int err = 0;
+
+	dev_info(&pdev->dev, "Requested num VFs: %d\n", numvfs);
+
+	if (numvfs > 0)
+		err = pci_enable_sriov(pdev, numvfs);
+	else
+		pci_disable_sriov(pdev);
+
+	return err ? err : numvfs;
+}
+
 static const struct pci_device_id mana_id_table[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_MICROSOFT, MANA_PF_DEVICE_ID) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_MICROSOFT, MANA_VF_DEVICE_ID) },
@@ -2276,6 +2295,7 @@ static struct pci_driver mana_driver = {
 	.suspend	= mana_gd_suspend,
 	.resume		= mana_gd_resume,
 	.shutdown	= mana_gd_shutdown,
+	.sriov_configure = mana_sriov_configure,
 };
 
 static int __init mana_driver_init(void)
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 91ac4e37ecb9..5a701f44b8fd 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -1127,6 +1127,7 @@ void pci_vf_drivers_autoprobe(struct pci_dev *dev, bool auto_probe)
 	if (dev->is_physfn)
 		dev->sriov->drivers_autoprobe = auto_probe;
 }
+EXPORT_SYMBOL_GPL(pci_vf_drivers_autoprobe);
 
 /**
  * pci_iov_bus_range - find bus range used by Virtual Function
-- 
2.34.1

Re: [PATCH net-next] net: mana: Add handler for sriov configure

[Bjorn Helgaas]

On Fri, May 08, 2026 at 03:04:06PM -0700, Haiyang Zhang wrote:
> From: Haiyang Zhang <haiyangz@microsoft.com>
> 
> Add callback function for the pci_driver, sriov_configure.
> 
> Also disable VF autoprobe when it runs as PF driver on bare metal,
> since the hardware side may not have the VF ready immediately.
> 
> Export pci_vf_drivers_autoprobe() so the driver can toggle the VF
> autoprobe flag.

Technically pci_vf_drivers_autoprobe() doesn't *toggle* the autoprobe
flag.  That would mean setting it to the opposite of its current
value.

Here I would say "so the driver can prevent autoprobing of the VFs",
which is the intent.

Out of curiosity, how do the VFs eventually get probed?  I guess
there's some other mechanism that tells you when they're ready, and
you manually use sysfs 'sriov_drivers_autoprobe' to enable probing,
then bind drivers to them via sysfs?

The prevention of autoprobing sounds like a critical part of this
change; might be worth saying something in the subject, because "add
sriov configure" doesn't include much information.

> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

I assume this would go via a net tree since that's where the bulk of
the changes are.

> ---
>  .../net/ethernet/microsoft/mana/gdma_main.c   | 20 +++++++++++++++++++
>  drivers/pci/iov.c                             |  1 +
>  2 files changed, 21 insertions(+)
> 
> diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> index 3bc3fff55999..767f11d5b351 100644
> --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> @@ -2094,6 +2094,11 @@ static int mana_gd_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  
>  	gc->numa_node = dev_to_node(&pdev->dev);
>  	gc->is_pf = mana_is_pf(pdev->device);
> +
> +	/* Disable VF autoprobe on BM */
> +	if (gc->is_pf)
> +		pci_vf_drivers_autoprobe(pdev, false);
> +
>  	gc->bar0_va = bar0_va;
>  	gc->dev = &pdev->dev;
>  	xa_init(&gc->irq_contexts);
> @@ -2262,6 +2267,20 @@ static void mana_gd_shutdown(struct pci_dev *pdev)
>  	pci_disable_device(pdev);
>  }
>  
> +static int mana_sriov_configure(struct pci_dev *pdev, int numvfs)
> +{
> +	int err = 0;
> +
> +	dev_info(&pdev->dev, "Requested num VFs: %d\n", numvfs);
> +
> +	if (numvfs > 0)
> +		err = pci_enable_sriov(pdev, numvfs);
> +	else
> +		pci_disable_sriov(pdev);
> +
> +	return err ? err : numvfs;
> +}
> +
>  static const struct pci_device_id mana_id_table[] = {
>  	{ PCI_DEVICE(PCI_VENDOR_ID_MICROSOFT, MANA_PF_DEVICE_ID) },
>  	{ PCI_DEVICE(PCI_VENDOR_ID_MICROSOFT, MANA_VF_DEVICE_ID) },
> @@ -2276,6 +2295,7 @@ static struct pci_driver mana_driver = {
>  	.suspend	= mana_gd_suspend,
>  	.resume		= mana_gd_resume,
>  	.shutdown	= mana_gd_shutdown,
> +	.sriov_configure = mana_sriov_configure,
>  };
>  
>  static int __init mana_driver_init(void)
> diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> index 91ac4e37ecb9..5a701f44b8fd 100644
> --- a/drivers/pci/iov.c
> +++ b/drivers/pci/iov.c
> @@ -1127,6 +1127,7 @@ void pci_vf_drivers_autoprobe(struct pci_dev *dev, bool auto_probe)
>  	if (dev->is_physfn)
>  		dev->sriov->drivers_autoprobe = auto_probe;
>  }
> +EXPORT_SYMBOL_GPL(pci_vf_drivers_autoprobe);
>  
>  /**
>   * pci_iov_bus_range - find bus range used by Virtual Function
> -- 
> 2.34.1
> 

RE: [EXTERNAL] Re: [PATCH net-next] net: mana: Add handler for sriov configure

[Haiyang Zhang]

> -----Original Message-----
> From: Bjorn Helgaas <helgaas@kernel.org>
> Sent: Friday, May 8, 2026 6:38 PM
> To: Haiyang Zhang <haiyangz@linux.microsoft.com>
> Cc: linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; KY Srinivasan
> <kys@microsoft.com>; Haiyang Zhang <haiyangz@microsoft.com>; Wei Liu
> <wei.liu@kernel.org>; Dexuan Cui <DECUI@microsoft.com>; Long Li
> <longli@microsoft.com>; Andrew Lunn <andrew+netdev@lunn.ch>; David S.
> Miller <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub
> Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Bjorn Helgaas
> <bhelgaas@google.com>; Simon Horman <horms@kernel.org>; Shradha Gupta
> <shradhagupta@linux.microsoft.com>; Dipayaan Roy
> <dipayanroy@linux.microsoft.com>; Erni Sri Satya Vennela
> <ernis@linux.microsoft.com>; linux-kernel@vger.kernel.org; linux-
> pci@vger.kernel.org; Paul Rosswurm <paulros@microsoft.com>
> Subject: [EXTERNAL] Re: [PATCH net-next] net: mana: Add handler for sriov
> configure
> 
> On Fri, May 08, 2026 at 03:04:06PM -0700, Haiyang Zhang wrote:
> > From: Haiyang Zhang <haiyangz@microsoft.com>
> >
> > Add callback function for the pci_driver, sriov_configure.
> >
> > Also disable VF autoprobe when it runs as PF driver on bare metal,
> > since the hardware side may not have the VF ready immediately.
> >
> > Export pci_vf_drivers_autoprobe() so the driver can toggle the VF
> > autoprobe flag.
> 
> Technically pci_vf_drivers_autoprobe() doesn't *toggle* the autoprobe
> flag.  That would mean setting it to the opposite of its current
> value.
> 
> Here I would say "so the driver can prevent autoprobing of the VFs",
> which is the intent.
Thanks, I will change the wording.

> 
> Out of curiosity, how do the VFs eventually get probed?  I guess
> there's some other mechanism that tells you when they're ready, and
> you manually use sysfs 'sriov_drivers_autoprobe' to enable probing,
> then bind drivers to them via sysfs?
We have a user program talking to the Azure backplane to get that information.
@Paul Rosswurm, do you have more details?


> The prevention of autoprobing sounds like a critical part of this
> change; might be worth saying something in the subject, because "add
> sriov configure" doesn't include much information.
How about "Add handler for sriov configure with VF autoprobe off"?

Thanks,
- Haiyang

Re: [EXTERNAL] Re: [PATCH net-next] net: mana: Add handler for sriov configure

[Bjorn Helgaas]

On Fri, May 08, 2026 at 10:47:14PM +0000, Haiyang Zhang wrote:
> > -----Original Message-----
> > From: Bjorn Helgaas <helgaas@kernel.org>
> > Sent: Friday, May 8, 2026 6:38 PM
> > To: Haiyang Zhang <haiyangz@linux.microsoft.com>
> > Cc: linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; KY Srinivasan
> > <kys@microsoft.com>; Haiyang Zhang <haiyangz@microsoft.com>; Wei Liu
> > <wei.liu@kernel.org>; Dexuan Cui <DECUI@microsoft.com>; Long Li
> > <longli@microsoft.com>; Andrew Lunn <andrew+netdev@lunn.ch>; David S.
> > Miller <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub
> > Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Bjorn Helgaas
> > <bhelgaas@google.com>; Simon Horman <horms@kernel.org>; Shradha Gupta
> > <shradhagupta@linux.microsoft.com>; Dipayaan Roy
> > <dipayanroy@linux.microsoft.com>; Erni Sri Satya Vennela
> > <ernis@linux.microsoft.com>; linux-kernel@vger.kernel.org; linux-
> > pci@vger.kernel.org; Paul Rosswurm <paulros@microsoft.com>
> > Subject: [EXTERNAL] Re: [PATCH net-next] net: mana: Add handler for sriov
> > configure
> > 
> > On Fri, May 08, 2026 at 03:04:06PM -0700, Haiyang Zhang wrote:
> > > From: Haiyang Zhang <haiyangz@microsoft.com>
> > >
> > > Add callback function for the pci_driver, sriov_configure.
> > >
> > > Also disable VF autoprobe when it runs as PF driver on bare metal,
> > > since the hardware side may not have the VF ready immediately.
> > >
> > > Export pci_vf_drivers_autoprobe() so the driver can toggle the VF
> > > autoprobe flag.
> > 
> > Technically pci_vf_drivers_autoprobe() doesn't *toggle* the autoprobe
> > flag.  That would mean setting it to the opposite of its current
> > value.
> > 
> > Here I would say "so the driver can prevent autoprobing of the VFs",
> > which is the intent.
> Thanks, I will change the wording.
> 
> > 
> > Out of curiosity, how do the VFs eventually get probed?  I guess
> > there's some other mechanism that tells you when they're ready, and
> > you manually use sysfs 'sriov_drivers_autoprobe' to enable probing,
> > then bind drivers to them via sysfs?
> We have a user program talking to the Azure backplane to get that information.
> @Paul Rosswurm, do you have more details?
> 
> 
> > The prevention of autoprobing sounds like a critical part of this
> > change; might be worth saying something in the subject, because "add
> > sriov configure" doesn't include much information.
> How about "Add handler for sriov configure with VF autoprobe off"?

OK by me :)

Re: [PATCH net-next] net: mana: Add handler for sriov configure

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Missing `pci_disable_sriov()` in PF driver's `remove` and `shutdown` paths causes resource leaks and potential Use-After-Free.
- [Medium] Missing VF assignment check in `mana_sriov_configure` causes silent failure when disabling SR-IOV.
--

commit 1f4061f22025ea097273f720b3bccac577e7d805
Author: Haiyang Zhang <haiyangz@microsoft.com>

net: mana: Add handler for sriov configure

This commit adds the sriov_configure callback to the mana pci_driver to handle
SR-IOV configuration. It also exports pci_vf_drivers_autoprobe() and disables
VF autoprobe when running as a PF driver on bare metal.

> diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> index 3bc3fff559991..767f11d5b351b 100644
> --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
[ ... ]
> @@ -2262,6 +2267,20 @@ static void mana_gd_shutdown(struct pci_dev *pdev)
>  	pci_disable_device(pdev);
>  }

Does this code need to explicitly call pci_disable_sriov() during driver
remove and shutdown?

If the PF driver is unbound while VFs are enabled, the PCI core logs a
warning but does not automatically disable SR-IOV. With the VFs remaining
active, could they interact with dead hardware or trigger host-side PF events
that rely on the freed gdma_context, resulting in a use-after-free?

> +static int mana_sriov_configure(struct pci_dev *pdev, int numvfs)
> +{
> +	int err = 0;
> +
> +	dev_info(&pdev->dev, "Requested num VFs: %d\n", numvfs);
> +
> +	if (numvfs > 0)
> +		err = pci_enable_sriov(pdev, numvfs);
> +	else
> +		pci_disable_sriov(pdev);
> +
> +	return err ? err : numvfs;

If VFs are currently assigned to a guest VM (e.g., via VFIO), the PCI core's
sriov_disable() will internally abort the teardown. Because
pci_disable_sriov() returns void, will this function return 0 and falsely
signal to userspace that the disable operation succeeded?

Should this code check pci_vfs_assigned(pdev) and return -EPERM, or use
the generic pci_sriov_configure_simple() helper instead?

> +}
> +

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260508220412.15138-1-haiyangz@linux.microsoft.com?part=1