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

["Tan, Jianfeng" <jianfeng.tan@intel.com>]

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>
>
> >
>
> > 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())
>
> > >
>
> >
>
> >
>