lkml.org 
[lkml]   [2017]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [Xen-devel] [PATCH] Xen/pciback: Implement PCI slot or bus reset with 'do_flr' SysFS attribute
Hi,

On Wed, Nov 08, 2017 at 09:44:48AM -0600, Govinda Tatti wrote:
> Thanks Jan for your review comments. Please see below for my comments.
>
> On 11/7/2017 8:40 AM, Jan Beulich wrote:
> >>>>On 06.11.17 at 18:48, <Govinda.Tatti@Oracle.COM> wrote:
> >>--- a/Documentation/ABI/testing/sysfs-driver-pciback
> >>+++ b/Documentation/ABI/testing/sysfs-driver-pciback
> >>@@ -11,3 +11,15 @@ Description:
> >> #echo 00:19.0-E0:2:FF > /sys/bus/pci/drivers/pciback/quirks
> >> will allow the guest to read and write to the configuration
> >> register 0x0E.
> >>+
> >>+What: /sys/bus/pci/drivers/pciback/do_flr
> >>+Date: Nov 2017
> >>+KernelVersion: 4.15
> >>+Contact: xen-devel@lists.xenproject.org
> >>+Description:
> >>+ An option to perform a slot or bus reset when a PCI device
> >>+ is owned by Xen PCI backend. Writing a string of DDDD:BB:DD.F
> >>+ will cause the pciback driver to perform a slot or bus reset
> >>+ if the device supports it. It also checks to make sure that
> >>+ all of the devices under the bridge are owned by Xen PCI
> >>+ backend.
> >Why do you name this "do_flr" when you don't even try FLR, but
> >go to slot or then bus reset right away.
> Yes, I agree but xen toolstack has already been modified to consume"do_flr"
> attribute. Hence, we are using the
> function that matches with sysfs attribute.
>

Hmm.. I remember some discussion from ages ago related to this.

Back then it was suggested to "emulate" the flr capability (by doing slot or bus reset) for devices which don't have *native* flr available? So is this patch perhaps related to that?

If the PCI device in question has native flr capability, then native flr is used, right ?
I guess I should read the full patch..

-- Pasi

\
 
 \ /
  Last update: 2017-11-08 21:13    [W:0.176 / U:0.156 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site