Re: [Xen-devel] [PATCH for-4.5] reset PCI devices on force removal even when QEMU returns error

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 12 Dec 2014, Konrad Rzeszutek Wilk wrote:
> On Fri, Dec 12, 2014 at 04:13:52PM +0100, Sander Eikelenboom wrote:
> > Hi Konrad,
> > 
> > This doesn't seem to be applied yet, nor does it seem to have a 
> > release-(N)ACK 
> > from you ?
> 
> Hm, Stefano:
> 
> - Is this a regression?

I don't think so. Probably a regression compared to the xend toolstack
though.


> - What are the risks of this not going in? I presume that it just means
>   we haven't reset it in sysfs. But the xc_deassign_device operation
>   if not done will not affect the hypervisor - which will move the
>   device to dom0 upon guest teardown.

The device becomes unusable until somebody manually resets it.


> > 
> > --
> > Sander
> > 
> > 
> > 
> > Friday, November 28, 2014, 5:53:09 PM, you wrote:
> > 
> > > On do_pci_remove when QEMU returns error, we just bail out early without
> > > resetting the device. On domain shutdown we are racing with QEMU exiting
> > > and most often QEMU closes the QMP connection before executing the
> > > requested command.
> > 
> > > In these cases if force=1, it makes sense to go ahead with rest of the
> > > PCI device removal, that includes resetting the device and calling
> > > xc_deassign_device. Otherwise we risk not resetting the device properly
> > > on domain shutdown.
> > 
> > > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > 
> > > diff --git a/tools/libxl/libxl_pci.c b/tools/libxl/libxl_pci.c
> > > index 316643c..0ac0b93 100644
> > > --- a/tools/libxl/libxl_pci.c
> > > +++ b/tools/libxl/libxl_pci.c
> > > @@ -1243,7 +1245,7 @@ static int do_pci_remove(libxl__gc *gc, uint32_t 
> > > domid,
> > >              rc = ERROR_INVAL;
> > >              goto out_fail;
> > >          }
> > > -        if (rc) {
> > > +        if (rc && !force) {
> > >              rc = ERROR_FAIL;
> > >              goto out_fail;
> > >          }
> > 
> > 
> 

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