[dpdk-dev] [dpdk-stable] [PATCH v2] igb_uio: prevent reset for a list of devices

Stephen Hemminger stephen at networkplumber.org
Tue Nov 14 00:46:56 CET 2017


On Wed, 8 Nov 2017 07:00:23 -0500
Chas Williams <3chas3 at gmail.com> wrote:

> On Tue, Nov 7, 2017 at 5:26 PM, Ferruh Yigit <ferruh.yigit at intel.com> wrote:
> On 11/7/2017 12:47 PM, Chas Williams wrote:
> > I will confess I haven't looked into the issue too hard since I have a
> > workaround.  My first guess is that there is something going on with the IOMMU
> > and quiescing a PCI pass-through device/function from the guest (since I don't
> > think the IOMMU is "visible" to the guest) seems iffy.
> >
> > Most devices have some sort of reset to put the device into a known state for
> > setup/configuration (or enable/disable for the DMA engines).  If this is done at
> > .dev_close(), shouldn't that be as sufficient as resetting the function?
> 
> This is for the cases DPDK app terminated unexpectedly, proper exit path already
> does cleanup.
> 
> Call a usermode helper from igb_uio that does an open/close on the device about to be released?

usermode helper is hated by upstream kernel developers. There are many problems
such as what namespace and security.


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