Re: [RFC PATCH] igb_uio: issue FLR during open and release of device file

[Gregory Etelson <gregory@weka.io>]

Hello Jianfeng,

I was experimenting with pci_disable_device() in release
Tests running on Intel 82599 VF crashed server after process down,
before a new instance was started.
Tests running on Intel XL710 VF did not crash server, but could not send / receive Ethernet frames
although all DPDK initialization routines completed without errors

Regards,
Gregory



    
Hi Gregory,        
On 6/4/2017 3:22 PM, Gregory Etelson      wrote:        
                        
In my environment I could reproduce server crash       
after applying the patch            Different from your patch, my patch calls    pci_enable_device()/pci_disable_device() instead of    pci_reset_function()/pci_try_reset_function() separately in open()    and release(). Could you check if that's the reason?        vfio_pci actually calls both pci_try_reset_function() and    pci_disable_device() in release().        Thanks,    Jianfeng        
      
      
Regards,      
Gregory      
      
      
On Wednesday, 31 May 2017 15:20:08 IDT Ferruh Yigit wrote:      
> On 5/31/2017 12:09 PM, Shijith Thotton wrote:      
> > Set UIO info device file operations open and release. Call pci reset      
> > function inside open and release to clear device state at start and      
> > end. Copied this behaviour from vfio_pci kernel module code. With this      
> > change, it is not mandatory to issue FLR by PMD's during init and close.      
>       
> Cc: Jianfeng Tan <jianfeng.tan@intel.com>[1]      
>       
> Jianfeng also implemented following patch:      
> http://dpdk.org/dev/patchwork/patch/17495/[2]      
>       
> Which also implements release and open ops, for slightly different      
> reason (prevent DMA access after app exit), but mainly both are to      
> gracefully handle application exit status.      
>       
> btw, for Jianfeng's case, can adding pci_clear_master() in release and      
> moving pci_set_master() to open help preventing unwanted DMA?      
>       
>       
> Gregory,      
>       
> Can you please check if this patch fixes your issue?      
>       
> Thanks,      
> ferruh      
>       
> >       
> > Signed-off-by: Shijith Thotton <shijith.thotton@caviumnetworks.com>[3]      
> > ---      
> >  lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 30 ++++++++++++++++++++++++++++++      
> >  1 file changed, 30 insertions(+)      
> >       
> > diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c      
> > index b9d427c..5bc58d2 100644      
> > --- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c      
> > +++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c      
> > @@ -170,6 +170,34 @@ struct rte_uio_pci_dev {      
> >  	return IRQ_HANDLED;      
> >  }      
> >        
> > +/**      
> > + * This gets called while opening uio device file. It clears any previous state      
> > + * associated with the pci device.      
> > + */      
> > +static int      
> > +igbuio_pci_open(struct uio_info *info, struct inode *inode)      
> > +{      
> > +	struct rte_uio_pci_dev *udev = info->priv;      
> > +	struct pci_dev *dev = udev->pdev;      
> > +      
> > +	/* reset the pci device */      
> > +	pci_reset_function(dev);      
> > +      
> > +	return 0;      
> > +}      
> > +      
> > +static int      
> > +igbuio_pci_release(struct uio_info *info, struct inode *inode)      
> > +{      
> > +	struct rte_uio_pci_dev *udev = info->priv;      
> > +	struct pci_dev *dev = udev->pdev;      
> > +      
> > +	/* try to reset the pci device */      
> > +	pci_try_reset_function(dev);      
> > +      
> > +	return 0;      
> > +}      
> > +      
> >  #ifdef CONFIG_XEN_DOM0      
> >  static int      
> >  igbuio_dom0_mmap_phys(struct uio_info *info, struct vm_area_struct *vma)      
> > @@ -372,6 +400,8 @@ struct rte_uio_pci_dev {      
> >  	udev->info.version = "0.1";      
> >  	udev->info.handler = igbuio_pci_irqhandler;      
> >  	udev->info.irqcontrol = igbuio_pci_irqcontrol;      
> > +	udev->info.open = igbuio_pci_open;      
> > +	udev->info.release = igbuio_pci_release;      
> >  #ifdef CONFIG_XEN_DOM0      
> >  	/* check if the driver run on Xen Dom0 */      
> >  	if (xen_initial_domain())      
> >       
>       
>       
          



--------
[1] mailto:jianfeng.tan@intel.com
[2] http://dpdk.org/dev/patchwork/patch/17495/
[3] mailto:shijith.thotton@caviumnetworks.com