[PATCH net-next v3] net: mana: Add handler for sriov configure

[PATCH net-next v3] net: mana: Add handler for sriov configure

[Haiyang Zhang]

From: Haiyang Zhang <haiyangz@microsoft.com>

Add callback function for the pci_driver / sriov_configure.

It asks the NIC to provide certain number of VFs, or disable
VFs if the request is zero.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
v3:
  Updated sriov disabling paths suggested by Paolo Abeni

v2:
  No longer change VF autoprobe as discussed with Leon Romanovsky and Bjorn Helgaas.

---
 .../net/ethernet/microsoft/mana/gdma_main.c   | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index aef3b77229c1..80a9118a90bc 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -2456,6 +2456,8 @@ static void mana_gd_remove(struct pci_dev *pdev)
 {
 	struct gdma_context *gc = pci_get_drvdata(pdev);
 
+	pci_disable_sriov(pdev);
+
 	mana_rdma_remove(&gc->mana_ib);
 	mana_remove(&gc->mana, false);
 
@@ -2517,6 +2519,8 @@ static void mana_gd_shutdown(struct pci_dev *pdev)
 
 	dev_info(&pdev->dev, "Shutdown was called\n");
 
+	pci_disable_sriov(pdev);
+
 	mana_rdma_remove(&gc->mana_ib);
 	mana_remove(&gc->mana, true);
 
@@ -2525,6 +2529,27 @@ 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 {
+		if (pci_vfs_assigned(pdev)) {
+			dev_warn(&pdev->dev,
+				 "Cannot disable SR-IOV while VFs are assigned\n");
+			return -EPERM;
+		}
+
+		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_PF2_DEVICE_ID) },
@@ -2540,6 +2565,7 @@ 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)
-- 
2.34.1

Re: [PATCH net-next v3] net: mana: Add handler for sriov configure

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Calling `pci_disable_sriov()` in the PF's `shutdown` path forces the teardown of already-shut-down VFs, triggering a `dev_WARN_ONCE` stack trace that can cause a kernel panic on shutdown.
--

--- Patch [1]: [PATCH net-next v3] net: mana: Add handler for sriov configure ---
commit 4f33a45546e7a470eda04866cd0e6294bcfd526c
Author: Haiyang Zhang <haiyangz@microsoft.com>

net: mana: Add handler for sriov configure

This patch adds an SR-IOV configuration handler to the mana driver, allowing
it to request or disable VFs. It also adds SR-IOV disable calls to the
device remove and shutdown paths.

> diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> index e8b7ffb47eb98..dff66a2a4f598 100644
> --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
[ ... ]
> @@ -2488,6 +2490,8 @@ static void mana_gd_shutdown(struct pci_dev *pdev)
>  
>  	dev_info(&pdev->dev, "Shutdown was called\n");
>  
> +	pci_disable_sriov(pdev);
> +

[Severity: High]
Will this trigger a kernel warning during system shutdown when VFs are active?

During system shutdown, the driver core calls device_shutdown() iterating in
reverse creation order. First, it calls mana_gd_shutdown() on the VFs, which
partially tears down the VF and disables the PCI device:

mana_gd_shutdown()
    ...
    pci_disable_device(pdev); 

Next, device_shutdown() calls mana_gd_shutdown() on the PF. Calling
pci_disable_sriov() here destroys the VF PCI devices and unregisters them
from the bus, which synchronously forces a call to the VF's remove callback:

mana_gd_remove()
    ...
    pci_disable_device(pdev); 

Since pci_disable_device() is called unconditionally at the end of both
mana_gd_shutdown() and mana_gd_remove(), this second call detects that the
device is already disabled and fires a warning. On production systems with
panic_on_warn=1, this converts a normal shutdown into a kernel panic.

>  	mana_rdma_remove(&gc->mana_ib);
>  	mana_remove(&gc->mana, true);
[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260708205924.2408673-1-haiyangz@linux.microsoft.com?part=1

RE: [PATCH net-next v3] net: mana: Add handler for sriov configure

[Haiyang Zhang]

> -----Original Message-----
> From: Haiyang Zhang <haiyangz@linux.microsoft.com>
> Sent: Wednesday, July 8, 2026 4:59 PM
> To: 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>; Simon Horman
> <horms@kernel.org>; Erni Sri Satya Vennela <ernis@linux.microsoft.com>;
> Dipayaan Roy <dipayanroy@linux.microsoft.com>; Aditya Garg
> <gargaditya@linux.microsoft.com>; Shradha Gupta
> <shradhagupta@linux.microsoft.com>; linux-kernel@vger.kernel.org
> Cc: Paul Rosswurm <paulros@microsoft.com>
> Subject: [PATCH net-next v3] net: mana: Add handler for sriov configure
> 
> From: Haiyang Zhang <haiyangz@microsoft.com>
> 
> Add callback function for the pci_driver / sriov_configure.
> 
> It asks the NIC to provide certain number of VFs, or disable
> VFs if the request is zero.
> 
> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> ---
> v3:
>   Updated sriov disabling paths suggested by Paolo Abeni
> 
> v2:
>   No longer change VF autoprobe as discussed with Leon Romanovsky and
> Bjorn Helgaas.
> 
> ---
>  .../net/ethernet/microsoft/mana/gdma_main.c   | 26 +++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> index aef3b77229c1..80a9118a90bc 100644
> --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> @@ -2456,6 +2456,8 @@ static void mana_gd_remove(struct pci_dev *pdev)
>  {
>  	struct gdma_context *gc = pci_get_drvdata(pdev);
> 
> +	pci_disable_sriov(pdev);
> +
>  	mana_rdma_remove(&gc->mana_ib);
>  	mana_remove(&gc->mana, false);
> 
> @@ -2517,6 +2519,8 @@ static void mana_gd_shutdown(struct pci_dev *pdev)
> 
>  	dev_info(&pdev->dev, "Shutdown was called\n");
> 
> +	pci_disable_sriov(pdev);
> +

I will remove this unnecessary pci_disable_sriov() as found by AI review,
and submit an updated patch.

- Haiyang