From: Govinda Tatti <Govinda.Tatti@Oracle.COM>
To: Jan Beulich <JBeulich@suse.com>
Cc: Juergen Gross <jgross@suse.com>,
xen-devel@lists.xenproject.org, boris.ostrovsky@Oracle.COM,
linux-kernel@vger.kernel.org, roger.pau@citrix.com
Subject: Re: [Xen-devel] [PATCH V2] Xen/pciback: Implement PCI slot or bus reset with 'do_flr' SysFS attribute
Date: Mon, 4 Dec 2017 10:16:31 -0600 [thread overview]
Message-ID: <3f240272-82a0-7d4e-df9c-1c4c590dfd1b@Oracle.COM> (raw)
In-Reply-To: <5151c992-b4d8-7cf6-8ec6-cd8b621d6902@oracle.com>
Jan,
Do you have any further comments on the current version of this patch?.
Otherwise, I will work on the review comments and publish next version
of this patch later this week. Please let me know. Thanks.
Cheers
GOVINDA
On 12/1/2017 10:16 AM, Govinda Tatti wrote:
>
> On 11/30/2017 8:46 AM, Jan Beulich wrote:
>>>>> On 30.11.17 at 15:15, <govinda.tatti@oracle.com> wrote:
>>> On 11/30/2017 2:27 AM, Jan Beulich wrote:
>>>>>>> On 29.11.17 at 18:38, <govinda.tatti@oracle.com> wrote:
>>>>>>> In the case of bus or slot reset, our goal is to reset connected
>>>>>>> PCIe
>>>>>>> fabric/card/endpoint.
>>>>>>> The connected card/endpoint can be multi-function device. So, same
>>>>>>> walk-through and checking
>>>>>>> is needed irrespective of type of reset being used.
>>>>>> I don't follow: The scope of other devices/functions possibly
>>>>>> affected by a reset depends on the type of reset, doesn't it?
>>>>> For PCIe platforms, both slot and bus reset endup resetting all
>>>>> connected
>>>>> device/functions on thesecondary bus (behind the root-port or
>>>>> downstream-port).
>>>> According to my understanding this contradicts the comment
>>>> ahead of pci_reset_slot(), which talks of multiple slots per bus.
>>>> In such a setup, I can't see why resetting on slot would affect
>>>> other slots on the same bus. At the same time the comment
>>>> says that the slot reset may resolve to a bus one when there's
>>>> just a single slot on the bus.
>>> For legacy PCI/PCI-X, we can have multiple slots per bus but not with
>>> PCI-Express
>>> (each link will be on a separate bus).
>> Is that true even for root complex integrated end points? A
>> random system's lspci output doesn't seem to agree with what
>> you say. A typical example would be USB controllers all sitting
>> on bus 0, but having different slot numbers. You clearly won't
>> be able to ever bus-reset these, and if you checked all devices
>> on bus 0 you would then also not be able to slot-reset them.
> Here, slot reset refers to any PCIe slot that implements or supports
> hotplug feature. The slot reset ultimately invokes "pciehp_reset_slot()".
> W.r.t integrated endpoints, these can be reset either through FLR or
> secondary bus reset methods only.
>
> Cheers
> GOVINDA
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xenproject.org
> https://lists.xenproject.org/mailman/listinfo/xen-devel
next prev parent reply other threads:[~2017-12-04 16:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-08 23:06 [PATCH V2] Xen/pciback: Implement PCI slot or bus reset with 'do_flr' SysFS attribute Govinda Tatti
2017-11-09 8:49 ` Jan Beulich
2017-11-29 15:37 ` [Xen-devel] " Govinda Tatti
2017-11-29 15:50 ` Jan Beulich
2017-11-29 17:38 ` Govinda Tatti
2017-11-30 8:27 ` Jan Beulich
2017-11-30 14:15 ` Govinda Tatti
2017-11-30 14:46 ` Jan Beulich
2017-12-01 16:16 ` Govinda Tatti
2017-12-04 16:16 ` Govinda Tatti [this message]
2017-12-04 16:49 ` Jan Beulich
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3f240272-82a0-7d4e-df9c-1c4c590dfd1b@Oracle.COM \
--to=govinda.tatti@oracle.com \
--cc=JBeulich@suse.com \
--cc=boris.ostrovsky@Oracle.COM \
--cc=jgross@suse.com \
--cc=linux-kernel@vger.kernel.org \
--cc=roger.pau@citrix.com \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).