Patchwork [5/5] ixgbe: add driver set_max_vfs support

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Submitter Yinghai Lu
Date Oct. 3, 2012, 5:51 p.m.
Message ID <1349286695-26713-6-git-send-email-yinghai@kernel.org>
Download mbox | patch
Permalink /patch/188879/
State Superseded
Headers show

Comments

Yinghai Lu - Oct. 3, 2012, 5:51 p.m.
Need ixgbe guys to close the loop to use set_max_vfs instead
kernel parameters.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Greg Rose <gregory.v.rose@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: e1000-devel@lists.sourceforge.net
Cc: netdev@vger.kernel.org
---
 drivers/net/ethernet/intel/ixgbe/ixgbe.h      |    2 +
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |   44 +++++++++++++++++++-----
 2 files changed, 37 insertions(+), 9 deletions(-)
Dan Carpenter - Oct. 3, 2012, 6:45 p.m.
On Wed, Oct 03, 2012 at 10:51:35AM -0700, Yinghai Lu wrote:
> Need ixgbe guys to close the loop to use set_max_vfs instead
> kernel parameters.
> 
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
> Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
> Cc: Greg Rose <gregory.v.rose@intel.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: John Fastabend <john.r.fastabend@intel.com>
> Cc: e1000-devel@lists.sourceforge.net
> Cc: netdev@vger.kernel.org
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe.h      |    2 +
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |   44 +++++++++++++++++++-----
>  2 files changed, 37 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> index b9623e9..d39d975 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> @@ -558,6 +558,8 @@ struct ixgbe_adapter {
>  	u32 interrupt_event;
>  	u32 led_reg;
>  
> +	struct ixgbe_info *ixgbe_info;
> +
>  #ifdef CONFIG_IXGBE_PTP
>  	struct ptp_clock *ptp_clock;
>  	struct ptp_clock_info ptp_caps;
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index ee61819..1c097c7 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -129,13 +129,6 @@ static struct notifier_block dca_notifier = {
>  };
>  #endif
>  
> -#ifdef CONFIG_PCI_IOV
> -static unsigned int max_vfs;
> -module_param(max_vfs, uint, 0);
> -MODULE_PARM_DESC(max_vfs,
> -		 "Maximum number of virtual functions to allocate per physical function - default is zero and maximum value is 63");
> -#endif /* CONFIG_PCI_IOV */
> -
>  static unsigned int allow_unsupported_sfp;
>  module_param(allow_unsupported_sfp, uint, 0);
>  MODULE_PARM_DESC(allow_unsupported_sfp,
> @@ -4496,7 +4489,7 @@ static int __devinit ixgbe_sw_init(struct ixgbe_adapter *adapter)
>  #ifdef CONFIG_PCI_IOV
>  	/* assign number of SR-IOV VFs */
>  	if (hw->mac.type != ixgbe_mac_82598EB)
> -		adapter->num_vfs = (max_vfs > 63) ? 0 : max_vfs;
> +		adapter->num_vfs = min_t(int, pdev->max_vfs, 63);

Could we make this min_t(uint, ...);

->max_vfs is type unsigned int. We take an unsigned long from sysfs.
We silently truncate it to an unsigned int.  Then we cast it to a
negative number and compare against 63 and take the minimum...

It's root only so it's not a problem but it's a hassle to audit.

regards,
dan carpenter

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Alexander Duyck - Oct. 3, 2012, 6:47 p.m.
On 10/03/2012 10:51 AM, Yinghai Lu wrote:
> Need ixgbe guys to close the loop to use set_max_vfs instead
> kernel parameters.
>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
> Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
> Cc: Greg Rose <gregory.v.rose@intel.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: John Fastabend <john.r.fastabend@intel.com>
> Cc: e1000-devel@lists.sourceforge.net
> Cc: netdev@vger.kernel.org
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe.h      |    2 +
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |   44 +++++++++++++++++++-----
>  2 files changed, 37 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> index b9623e9..d39d975 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
> @@ -558,6 +558,8 @@ struct ixgbe_adapter {
>  	u32 interrupt_event;
>  	u32 led_reg;
>  
> +	struct ixgbe_info *ixgbe_info;
> +
>  #ifdef CONFIG_IXGBE_PTP
>  	struct ptp_clock *ptp_clock;
>  	struct ptp_clock_info ptp_caps;
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> index ee61819..1c097c7 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
> @@ -129,13 +129,6 @@ static struct notifier_block dca_notifier = {
>  };
>  #endif
>  
> -#ifdef CONFIG_PCI_IOV
> -static unsigned int max_vfs;
> -module_param(max_vfs, uint, 0);
> -MODULE_PARM_DESC(max_vfs,
> -		 "Maximum number of virtual functions to allocate per physical function - default is zero and maximum value is 63");
> -#endif /* CONFIG_PCI_IOV */
> -
>  static unsigned int allow_unsupported_sfp;
>  module_param(allow_unsupported_sfp, uint, 0);
>  MODULE_PARM_DESC(allow_unsupported_sfp,
> @@ -4496,7 +4489,7 @@ static int __devinit ixgbe_sw_init(struct ixgbe_adapter *adapter)
>  #ifdef CONFIG_PCI_IOV
>  	/* assign number of SR-IOV VFs */
>  	if (hw->mac.type != ixgbe_mac_82598EB)
> -		adapter->num_vfs = (max_vfs > 63) ? 0 : max_vfs;
> +		adapter->num_vfs = min_t(int, pdev->max_vfs, 63);
>  
>  #endif
>  	/* enable itr by default in dynamic mode */
> @@ -7220,8 +7213,9 @@ static int __devinit ixgbe_probe(struct pci_dev *pdev,
>  
>  #ifdef CONFIG_PCI_IOV
>  	ixgbe_enable_sriov(adapter, ii);
> -
>  #endif
> +	adapter->ixgbe_info = ii;
> +
>  	netdev->features = NETIF_F_SG |
>  			   NETIF_F_IP_CSUM |
>  			   NETIF_F_IPV6_CSUM |
> @@ -7683,11 +7677,43 @@ static const struct pci_error_handlers ixgbe_err_handler = {
>  	.resume = ixgbe_io_resume,
>  };
>  
> +static void ixgbe_set_max_vfs(struct pci_dev *pdev)
> +{
> +#ifdef CONFIG_PCI_IOV
> +	struct ixgbe_adapter *adapter = pci_get_drvdata(pdev);
> +	struct ixgbe_hw *hw = &adapter->hw;
> +	int num_vfs = 0;
> +
> +	/* assign number of SR-IOV VFs */
> +	if (hw->mac.type != ixgbe_mac_82598EB)
> +		num_vfs = min_t(int, pdev->max_vfs, 63);
> +
> +	/* no change */
> +	if (adapter->num_vfs == num_vfs)
> +		return;
> +
> +	if (!num_vfs) {
> +		/* disable sriov */
> +		ixgbe_disable_sriov(adapter);
> +		adapter->num_vfs = 0;
> +	} else if (!adapter->num_vfs && num_vfs) {
> +		/* enable sriov */
> +		adapter->num_vfs = num_vfs;
> +		ixgbe_enable_sriov(adapter, adapter->ixgbe_info);
> +	} else {
> +		/* increase or decrease */
> +	}
> +
> +	pdev->max_vfs = adapter->num_vfs;
> +#endif
> +}
> +
>  static struct pci_driver ixgbe_driver = {
>  	.name     = ixgbe_driver_name,
>  	.id_table = ixgbe_pci_tbl,
>  	.probe    = ixgbe_probe,
>  	.remove   = __devexit_p(ixgbe_remove),
> +	.set_max_vfs = ixgbe_set_max_vfs,
>  #ifdef CONFIG_PM
>  	.suspend  = ixgbe_suspend,
>  	.resume   = ixgbe_resume,

The ixgbe_set_max_vfs function has several issues.  The two big ones are
that this function assumes it can just enable/disable SR-IOV without any
other changes being necessary which is not the case.  I would recommend
looking at ixgbe_setup_tc for how to do this properly.  Secondly is the
fact that this code will change the PF network device and as such
sections of the code should be called with the RTNL lock held.  In
addition I believe you have to disable SR-IOV before enabling it again
with a different number of VFs.

Below is a link to one of the early patches for igb when we were first
introducing SR-IOV, and the in-driver sysfs value had been rejected.  I
figure it might be useful as it was also using sysfs to enable/disable
VFs.  It however doesn't have the correct locking on changing the queues
and as such will likely throw an error if you were to implement it the
same way now:
http://lists.openwall.net/netdev/2009/04/08/34

Thanks,

Alex
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Don Dutile - Oct. 3, 2012, 7:02 p.m.
On 10/03/2012 02:47 PM, Alexander Duyck wrote:
> On 10/03/2012 10:51 AM, Yinghai Lu wrote:
>> Need ixgbe guys to close the loop to use set_max_vfs instead
>> kernel parameters.
>>
>> Signed-off-by: Yinghai Lu<yinghai@kernel.org>
>> Cc: Jeff Kirsher<jeffrey.t.kirsher@intel.com>
>> Cc: Jesse Brandeburg<jesse.brandeburg@intel.com>
>> Cc: Greg Rose<gregory.v.rose@intel.com>
>> Cc: "David S. Miller"<davem@davemloft.net>
>> Cc: John Fastabend<john.r.fastabend@intel.com>
>> Cc: e1000-devel@lists.sourceforge.net
>> Cc: netdev@vger.kernel.org
>> ---
>>   drivers/net/ethernet/intel/ixgbe/ixgbe.h      |    2 +
>>   drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |   44 +++++++++++++++++++-----
>>   2 files changed, 37 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>> index b9623e9..d39d975 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
>> @@ -558,6 +558,8 @@ struct ixgbe_adapter {
>>   	u32 interrupt_event;
>>   	u32 led_reg;
>>
>> +	struct ixgbe_info *ixgbe_info;
>> +
>>   #ifdef CONFIG_IXGBE_PTP
>>   	struct ptp_clock *ptp_clock;
>>   	struct ptp_clock_info ptp_caps;
>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>> index ee61819..1c097c7 100644
>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>> @@ -129,13 +129,6 @@ static struct notifier_block dca_notifier = {
>>   };
>>   #endif
>>
>> -#ifdef CONFIG_PCI_IOV
>> -static unsigned int max_vfs;
>> -module_param(max_vfs, uint, 0);
>> -MODULE_PARM_DESC(max_vfs,
>> -		 "Maximum number of virtual functions to allocate per physical function - default is zero and maximum value is 63");
>> -#endif /* CONFIG_PCI_IOV */
>> -
>>   static unsigned int allow_unsupported_sfp;
>>   module_param(allow_unsupported_sfp, uint, 0);
>>   MODULE_PARM_DESC(allow_unsupported_sfp,
>> @@ -4496,7 +4489,7 @@ static int __devinit ixgbe_sw_init(struct ixgbe_adapter *adapter)
>>   #ifdef CONFIG_PCI_IOV
>>   	/* assign number of SR-IOV VFs */
>>   	if (hw->mac.type != ixgbe_mac_82598EB)
>> -		adapter->num_vfs = (max_vfs>  63) ? 0 : max_vfs;
>> +		adapter->num_vfs = min_t(int, pdev->max_vfs, 63);
>>
>>   #endif
>>   	/* enable itr by default in dynamic mode */
>> @@ -7220,8 +7213,9 @@ static int __devinit ixgbe_probe(struct pci_dev *pdev,
>>
>>   #ifdef CONFIG_PCI_IOV
>>   	ixgbe_enable_sriov(adapter, ii);
>> -
>>   #endif
>> +	adapter->ixgbe_info = ii;
>> +
>>   	netdev->features = NETIF_F_SG |
>>   			   NETIF_F_IP_CSUM |
>>   			   NETIF_F_IPV6_CSUM |
>> @@ -7683,11 +7677,43 @@ static const struct pci_error_handlers ixgbe_err_handler = {
>>   	.resume = ixgbe_io_resume,
>>   };
>>
>> +static void ixgbe_set_max_vfs(struct pci_dev *pdev)
>> +{
>> +#ifdef CONFIG_PCI_IOV
>> +	struct ixgbe_adapter *adapter = pci_get_drvdata(pdev);
>> +	struct ixgbe_hw *hw =&adapter->hw;
>> +	int num_vfs = 0;
>> +
>> +	/* assign number of SR-IOV VFs */
>> +	if (hw->mac.type != ixgbe_mac_82598EB)
>> +		num_vfs = min_t(int, pdev->max_vfs, 63);
>> +
>> +	/* no change */
>> +	if (adapter->num_vfs == num_vfs)
>> +		return;
>> +
>> +	if (!num_vfs) {
>> +		/* disable sriov */
>> +		ixgbe_disable_sriov(adapter);
>> +		adapter->num_vfs = 0;
>> +	} else if (!adapter->num_vfs&&  num_vfs) {
>> +		/* enable sriov */
>> +		adapter->num_vfs = num_vfs;
>> +		ixgbe_enable_sriov(adapter, adapter->ixgbe_info);
>> +	} else {
>> +		/* increase or decrease */
>> +	}
>> +
>> +	pdev->max_vfs = adapter->num_vfs;
>> +#endif
>> +}
>> +
>>   static struct pci_driver ixgbe_driver = {
>>   	.name     = ixgbe_driver_name,
>>   	.id_table = ixgbe_pci_tbl,
>>   	.probe    = ixgbe_probe,
>>   	.remove   = __devexit_p(ixgbe_remove),
>> +	.set_max_vfs = ixgbe_set_max_vfs,
>>   #ifdef CONFIG_PM
>>   	.suspend  = ixgbe_suspend,
>>   	.resume   = ixgbe_resume,
>
> The ixgbe_set_max_vfs function has several issues.  The two big ones are
> that this function assumes it can just enable/disable SR-IOV without any
> other changes being necessary which is not the case.  I would recommend
> looking at ixgbe_setup_tc for how to do this properly.  Secondly is the
> fact that this code will change the PF network device and as such
> sections of the code should be called with the RTNL lock held.  In
> addition I believe you have to disable SR-IOV before enabling it again
> with a different number of VFs.
>
> Below is a link to one of the early patches for igb when we were first
> introducing SR-IOV, and the in-driver sysfs value had been rejected.  I
> figure it might be useful as it was also using sysfs to enable/disable
> VFs.  It however doesn't have the correct locking on changing the queues
> and as such will likely throw an error if you were to implement it the
> same way now:
> http://lists.openwall.net/netdev/2009/04/08/34
>
> Thanks,
>
> Alex

Alex,
Thanks for patch set pointer.
When I started to work on the ixgbe example use based on the RFC set I posted,
I ran into the problem you outlined -- the PF uses/consumes all the queues &
MSI intrs when sriov not enabled at driver load time, which required
more network shutdown logic that I'm not familiar with... So, I was going
to defer to Greg to work that magic. :)
Greg: assume the 2 callback function interface in the RFC patch set I sent,
       (primarily, just the include/linux/pci.h changes), and you can make the
       necessary drivers mods from there.  In the meantime, I'll make the changes
       to my original/v1 RFC to reflect the changes that GKH & Yinghai recommended/implemented
       for sysfs attribute creation & removal in a v2 posting.
       The end result is that the current module parameter setting for max_vfs should
       continue to work, and the sysfs interface will work when those pieces are provided.

-Don
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Rose, Gregory V - Oct. 3, 2012, 7:16 p.m.
> -----Original Message-----
> From: Don Dutile [mailto:ddutile@redhat.com]
> Sent: Wednesday, October 03, 2012 12:03 PM
> To: Duyck, Alexander H
> Cc: Yinghai Lu; Bjorn Helgaas; Greg Kroah-Hartman; linux-
> pci@vger.kernel.org; linux-kernel@vger.kernel.org; yuvalmin@broadcom.com;
> bhutchings@solarflare.com; Rose, Gregory V; davem@davemloft.net--no-chain-
> reply-to; Kirsher, Jeffrey T; Brandeburg, Jesse; David S. Miller;
> Fastabend, John R; e1000-devel@lists.sourceforge.net;
> netdev@vger.kernel.org
> Subject: Re: [PATCH 5/5] ixgbe: add driver set_max_vfs support
> 
> On 10/03/2012 02:47 PM, Alexander Duyck wrote:

[snip]

> >
> > The ixgbe_set_max_vfs function has several issues.  The two big ones
> > are that this function assumes it can just enable/disable SR-IOV
> > without any other changes being necessary which is not the case.  I
> > would recommend looking at ixgbe_setup_tc for how to do this properly.
> > Secondly is the fact that this code will change the PF network device
> > and as such sections of the code should be called with the RTNL lock
> > held.  In addition I believe you have to disable SR-IOV before
> > enabling it again with a different number of VFs.
> >
> > Below is a link to one of the early patches for igb when we were first
> > introducing SR-IOV, and the in-driver sysfs value had been rejected.
> > I figure it might be useful as it was also using sysfs to
> > enable/disable VFs.  It however doesn't have the correct locking on
> > changing the queues and as such will likely throw an error if you were
> > to implement it the same way now:
> > http://lists.openwall.net/netdev/2009/04/08/34
> >
> > Thanks,
> >
> > Alex
> 
> Alex,
> Thanks for patch set pointer.
> When I started to work on the ixgbe example use based on the RFC set I
> posted, I ran into the problem you outlined -- the PF uses/consumes all
> the queues & MSI intrs when sriov not enabled at driver load time, which
> required more network shutdown logic that I'm not familiar with... So, I
> was going to defer to Greg to work that magic. :)
> Greg: assume the 2 callback function interface in the RFC patch set I
> sent,
>        (primarily, just the include/linux/pci.h changes), and you can make
> the
>        necessary drivers mods from there.  In the meantime, I'll make the
> changes
>        to my original/v1 RFC to reflect the changes that GKH & Yinghai
> recommended/implemented
>        for sysfs attribute creation & removal in a v2 posting.
>        The end result is that the current module parameter setting for
> max_vfs should
>        continue to work, and the sysfs interface will work when those
> pieces are provided.

OK, I'll start work on it.

Thanks Don,

- Greg

> 
> -Don
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Yinghai Lu - Oct. 3, 2012, 8:37 p.m.
On Wed, Oct 3, 2012 at 11:47 AM, Alexander Duyck
<alexander.h.duyck@intel.com> wrote:
> The ixgbe_set_max_vfs function has several issues.  The two big ones are
> that this function assumes it can just enable/disable SR-IOV without any
> other changes being necessary which is not the case.  I would recommend
> looking at ixgbe_setup_tc for how to do this properly.  Secondly is the
> fact that this code will change the PF network device and as such
> sections of the code should be called with the RTNL lock held.  In
> addition I believe you have to disable SR-IOV before enabling it again
> with a different number of VFs.

yes, agreed.

>
> Below is a link to one of the early patches for igb when we were first
> introducing SR-IOV, and the in-driver sysfs value had been rejected.  I
> figure it might be useful as it was also using sysfs to enable/disable
> VFs.  It however doesn't have the correct locking on changing the queues
> and as such will likely throw an error if you were to implement it the
> same way now:
> http://lists.openwall.net/netdev/2009/04/08/34

yes, that is almost there if put that in-driver value to per device
value and ops.

Thanks

Yinghai
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Patch

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe.h b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
index b9623e9..d39d975 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe.h
@@ -558,6 +558,8 @@  struct ixgbe_adapter {
 	u32 interrupt_event;
 	u32 led_reg;
 
+	struct ixgbe_info *ixgbe_info;
+
 #ifdef CONFIG_IXGBE_PTP
 	struct ptp_clock *ptp_clock;
 	struct ptp_clock_info ptp_caps;
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index ee61819..1c097c7 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -129,13 +129,6 @@  static struct notifier_block dca_notifier = {
 };
 #endif
 
-#ifdef CONFIG_PCI_IOV
-static unsigned int max_vfs;
-module_param(max_vfs, uint, 0);
-MODULE_PARM_DESC(max_vfs,
-		 "Maximum number of virtual functions to allocate per physical function - default is zero and maximum value is 63");
-#endif /* CONFIG_PCI_IOV */
-
 static unsigned int allow_unsupported_sfp;
 module_param(allow_unsupported_sfp, uint, 0);
 MODULE_PARM_DESC(allow_unsupported_sfp,
@@ -4496,7 +4489,7 @@  static int __devinit ixgbe_sw_init(struct ixgbe_adapter *adapter)
 #ifdef CONFIG_PCI_IOV
 	/* assign number of SR-IOV VFs */
 	if (hw->mac.type != ixgbe_mac_82598EB)
-		adapter->num_vfs = (max_vfs > 63) ? 0 : max_vfs;
+		adapter->num_vfs = min_t(int, pdev->max_vfs, 63);
 
 #endif
 	/* enable itr by default in dynamic mode */
@@ -7220,8 +7213,9 @@  static int __devinit ixgbe_probe(struct pci_dev *pdev,
 
 #ifdef CONFIG_PCI_IOV
 	ixgbe_enable_sriov(adapter, ii);
-
 #endif
+	adapter->ixgbe_info = ii;
+
 	netdev->features = NETIF_F_SG |
 			   NETIF_F_IP_CSUM |
 			   NETIF_F_IPV6_CSUM |
@@ -7683,11 +7677,43 @@  static const struct pci_error_handlers ixgbe_err_handler = {
 	.resume = ixgbe_io_resume,
 };
 
+static void ixgbe_set_max_vfs(struct pci_dev *pdev)
+{
+#ifdef CONFIG_PCI_IOV
+	struct ixgbe_adapter *adapter = pci_get_drvdata(pdev);
+	struct ixgbe_hw *hw = &adapter->hw;
+	int num_vfs = 0;
+
+	/* assign number of SR-IOV VFs */
+	if (hw->mac.type != ixgbe_mac_82598EB)
+		num_vfs = min_t(int, pdev->max_vfs, 63);
+
+	/* no change */
+	if (adapter->num_vfs == num_vfs)
+		return;
+
+	if (!num_vfs) {
+		/* disable sriov */
+		ixgbe_disable_sriov(adapter);
+		adapter->num_vfs = 0;
+	} else if (!adapter->num_vfs && num_vfs) {
+		/* enable sriov */
+		adapter->num_vfs = num_vfs;
+		ixgbe_enable_sriov(adapter, adapter->ixgbe_info);
+	} else {
+		/* increase or decrease */
+	}
+
+	pdev->max_vfs = adapter->num_vfs;
+#endif
+}
+
 static struct pci_driver ixgbe_driver = {
 	.name     = ixgbe_driver_name,
 	.id_table = ixgbe_pci_tbl,
 	.probe    = ixgbe_probe,
 	.remove   = __devexit_p(ixgbe_remove),
+	.set_max_vfs = ixgbe_set_max_vfs,
 #ifdef CONFIG_PM
 	.suspend  = ixgbe_suspend,
 	.resume   = ixgbe_resume,