Re: [3.15-rc3] Bisected: xen-netback mangles packets between two guests on a bridge since merge of "TX grant mapping with SKBTX_DEV_ZEROCOPY instead of copy" series.
From: Sander Eikelenboom <hidden>
Date: 2014-05-01 14:05:16
Thursday, May 1, 2014, 3:49:45 PM, you wrote:
On 30/04/14 11:45, Sander Eikelenboom wrote:quoted
Another point would be: what *correctness* testing is actually done on the xen-net* patches ?I can speak only about my patches: I have manually tested them for the usecases where they likely to make a difference, plus they went through Xenserver's full test suite several times.
I think Paul's patches for 3.14 also went through this testsuite fine, however it did have a bug in it. Does this testsuite include a test which causes a diverse pattern of frags (for both tx and rx case) ?
quoted
As i suspect this is again about fragmented packets .. that doesn't seem to be included in any test case while it actually seems to be a case which is hard to get right...Beware, there are frags and frag_list which are two entirely different things with confusing names. In netback case, frags are used to pass through large packets for a long time. frag_list is used only since my grant mapping patches, to handle older guests (see comment in include/xen/interface/io/netif.h for XEN_NETIF_NR_SLOTS_MIN)
Ah ok .. it's not about the frags in the packets being handled, but the frag mechanism is supposed to be used internally ? If so .. there is at least something wrong in the "older guest" detection, because both dom0 and PV guests are running the same 3.15-rc3 kernel.
Zoli