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

[Gregory Etelson <gregory@weka.io>]

In my environment I could reproduce server crash 
after applying the patch

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>
> 
> Jianfeng also implemented following patch:
> http://dpdk.org/dev/patchwork/patch/17495/
> 
> 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>
> > ---
> >  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())
> > 
> 
>