RE: [EXTERNAL] Re: [PATCH net-next v2] net: mana: Add handler for sriov configure

> -----Original Message-----
> From: Paolo Abeni <[email protected]>
> Sent: Wednesday, July 8, 2026 4:09 AM
> To: [email protected]
> Cc: [email protected]; [email protected]; KY Srinivasan
> <[email protected]>; Haiyang Zhang <[email protected]>;
> [email protected]; Dexuan Cui <[email protected]>; Long Li
> <[email protected]>; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]; [email protected];
> [email protected]; [email protected];
> [email protected]; [email protected]; linux-
> [email protected]; Paul Rosswurm <[email protected]>
> Subject: [EXTERNAL] Re: [PATCH net-next v2] net: mana: Add handler for
> sriov configure
> 
> From: AI Reviewer <[email protected]>
> 
> This is an AI-generated review of your patch. The human sending this
> email has considered the AI review valid, or at least plausible.
> Full review at:
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> ---
> net: mana: Add handler for sriov configure
> 
> 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.
> 
> > diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> > index e8b7ffb47eb98..f7a79874fd0eb 100644
> > --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> > +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> > @@ -2496,6 +2496,20 @@ static void mana_gd_shutdown(struct pci_dev
> *pdev)
> >  	pci_disable_device(pdev);
> >  }
> 
> [Severity: High]
> With the addition of SR-IOV support in this patch, do mana_gd_shutdown()
> and
> mana_gd_remove() need to call pci_disable_sriov()?
> 
> If a user enables VFs via sysfs and then unbinds the driver or shuts down
> the
> system, could this omission introduce a regression where orphaned, dead VF
> PCI
> devices are left in the kernel?
> 
> Accessing these orphaned VFs might trigger use-after-free crashes or
> hardware
> faults, as the underlying PF hardware and driver context have been
> destroyed.
Will fix.

> 
> > +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);
> 
> [Severity: High]
> Should this path check if the VFs are currently assigned to a guest VM
> before
> disabling SR-IOV?
> 
> If a privileged user writes 0 to sriov_numvfs while VFs are actively
> assigned
> to a VM (e.g., via vfio-pci), could forcefully removing the PCI devices
> cause
> a regression resulting in host IOMMU faults and guest kernel panics?
> 
> Would it be better to check pci_vfs_assigned(pdev) here, or use the
> pci_sriov_configure_simple() helper to safely enforce this?

Will update.
I will send out an updated patch soon.

Thanks,
- Haiyang