Messages in this thread | | | Subject | Re: [Xen-devel] [PATCH] Xen/pciback: Implement PCI slot or bus reset with 'do_flr' SysFS attribute | From | Govinda Tatti <> | Date | Wed, 8 Nov 2017 17:26:47 -0600 |
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Thanks Pasi for your response. Please see below for my comments.
On 11/8/2017 11:38 AM, Pasi Kärkkäinen wrote: > 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? I don't think so but either Konrad or someone can comment on it. > > If the PCI device in question has native flr capability, then native flr is used, right ? Yes. > I guess I should read the full patch.. Please check it and let us know your comments.
Cheers GOVINDA
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