Re: [Xen-devel] [PATCH V3 2/2] Xen/PCIback: Implement PCI flr/slot/bus reset with 'reset' SysFS attribute

Govinda Tatti
2017-12-12T15:15:05Z

On 12/12/2017 9:01 AM, Jan Beulich wrote:
>>>> On 12.12.17 at 15:48, <Govinda.Tatti@Oracle.COM> wrote:
>> Thanks Jan for your review comments. Please see below for my comments.
> First of all - can you please do something about your reply style?
> HTML mail should be avoided. You'll see that the (plain text) reply
> as a result is rather hard to follow, too.
Sorry about it. I had an issue with my Thunderbird setting.
>
>> --- a/Documentation/ABI/testing/sysfs-driver-pciback
>> +++ b/Documentation/ABI/testing/sysfs-driver-pciback
>> @@ -11,3 +11,18 @@ 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/reset
>> +Date: Dec 2017
>> +KernelVersion: 4.15
>> +Contact: xen-devel@lists.xenproject.org
>> +Description:
>> + An option to perform a flr/slot/bus reset when a PCI device
>> + is owned by Xen PCI backend. Writing a string of DDDD:BB:DD.F
>> SSSS:BB:DD.F (or else the D-s are ambiguous, the more that "domain"
>> in Xen code is ambiguous anyway - I continue to be mislead by struct
>> pcistub_device_id's domain field) Thanks for catching this issue. I will
>> fix it.
>>
>>
>> Also I assume the SSSS part is optional (default zero), which
>> probably can and should be expressed in some way. SSSS can be 0 or
>> non-zero, subject to system configuration.
> The question isn't system configuration, but whether the field can
> be omitted on input, with zero being assumed in such a case. That's
> a common shorthand, considering that the vast majority of x86
> (and maybe other) systems aren't using segments other than zero
Yes, it can be omitted if SSSS is zero.I will add this information
to above documentation file.

Cheers
GOVINDA