Re: [Qemu-devel] [PATCH v5 0/8] e1000: Various fixes and registers' implementation

[Leonid Bloch <leonid.bloch@ravellosystems.com>]

On Tue, Nov 10, 2015 at 3:01 PM, Jason Wang <jasowang@redhat.com> wrote:
>
>
> On 11/10/2015 07:39 PM, Leonid Bloch wrote:
>> On Tue, Nov 10, 2015 at 8:21 AM, Jason Wang <jasowang@redhat.com> wrote:
>>>
>>> On 11/09/2015 10:59 PM, Leonid Bloch wrote:
>>>> This series fixes issues with packet/octet counting in e1000's Statistic
>>>> registers, fixes a bug in the packet address filtering procedure, and
>>>> implements many MAC registers that were absent before, some Statistic
>>>> counters among them.
>>>>
>>>> Besides this, the series introduces a parameter which, if set to "on"
>>>> (default), will cause the entire MAC registers' array to migrate during
>>>> live migration (please see patch #2 for details). The rational behind
>>>> this is the ability to implement additional MAC registers in the future,
>>>> without worrying about migration compatibility between future versions.
>>>> For compatibility with previous versions, the above mentioned parameter
>>>> can be set to "off".
>>>>
>>>> Also, a new array is introduced to control the access to the various MAC
>>>> registers. This takes care of situations when a MAC register requires a
>>>> certain parameter to be accessed, or is partially implemented, and
>>>> requires a debug warning to be printed on access attempts.
>>>>
>>>> Additionally, several cosmetic changes are made.
>>>>
>>>> Differences v1-2:
>>>> --------------------
>>>> * Wording of several commit messages corrected.
>>>> * For trivially implemented Diagnostic registers, a debug message is
>>>>   added on read/write attempts, alerting of incomplete implementation.
>>>> * Following testing on a physical device, only the lower 16 bits can now
>>>>   be read from AIT, and only the lower 4 - from FFMT*.
>>>> * The grow_8reg_if_not_full function is rewritten.
>>>> * inc_tx_bcast_or_mcast_count and increase_size_stats are now called
>>>>   from within e1000_send_packet, to avoid code duplication.
>>>>
>>>> Differences v2-3:
>>>> --------------------
>>>> * Minor rewordings of some commit messages (0002, 0003).
>>>> * Live migration capability is added to the newly implemented registers.
>>>>
>>>> Differences v3-4:
>>>> --------------------
>>>> * Introduction of the "full_mac_registers" parameter (see above).
>>>> * Reversion of the live migration handling introduced in v3.
>>>> * Small alignment changes in patch #1 to correspond with the following
>>>>   patches.
>>>>
>>>> Differences v4-v5:
>>>> --------------------
>>>> * Introduction of an array to control the access to the MAC registers.
>>>> * Removal of the specific functions that warned of partial
>>>>   implementation on read/write from patch 4.
>>>> * Adequate changes to patches 4 and 8: mainly adding the registers
>>>>   introduced there to the new array.
>>>>
>>>> The majority of these changes result from Jason Wang's review - thank
>>>> you, Jason!
>>> Thanks a lot for the patches. Almost done with two minor concerns:
>>>
>>> 1) to unbreak bisection we'd better enable the extra_mac_registers (and
>>> compatibility stuffs) in patch 8 or patch 9
>> Do you mean by that changing patch 2, so that the compatibility would
>> be "on" by default, and setting it to "off" by default only in patch
>> 8, or an additional patch 9?
>
> I mean do not introduce the property "extra_mac_registers" until patch 8
> and 9. In this case all function will be enabled completely at that time
> instead of partially patch by patch in this series.

But won't there be compatibility issues between the patches if done
like that? Why not to prepare the ground for compatibility, and only
then introduce the new registers (as it is done now)?
>
>>> 2) looks like we could save some lines of codes in patch 3, see the
>>> comment in that patch
>>>
>>> Since we're near to soft freeze (12th), want to ask whether or not you
>>> want to send a v6 or I can fix 1 my self. (if 2 is correct, we can do
>>> optimizations on top).
>> Will send a v6 with a fix to 2 today. Regarding 1 - awaiting your answer.
>>
>> Thanks,
>> Leonid.
>>>> Leonid Bloch (8):
>>>>   e1000: Cosmetic and alignment fixes
>>>>   e1000: Add support for migrating the entire MAC registers' array
>>>>   e1000: Introduced an array to control the access to the MAC registers
>>>>   e1000: Trivial implementation of various MAC registers
>>>>   e1000: Fixing the received/transmitted packets' counters
>>>>   e1000: Fixing the received/transmitted octets' counters
>>>>   e1000: Fixing the packet address filtering procedure
>>>>   e1000: Implementing various counters
>>>>
>>>>  hw/net/e1000.c      | 503 +++++++++++++++++++++++++++++++++++++++++-----------
>>>>  hw/net/e1000_regs.h |   8 +-
>>>>  include/hw/compat.h |   4 +
>>>>  3 files changed, 406 insertions(+), 109 deletions(-)
>>>>
>