Michael Roth <mdr...@linux.vnet.ibm.com> writes: > Quoting Michael Roth (2017-05-02 11:46:36) >> Quoting Eric Blake (2017-04-27 16:58:21) >> > Commit 62c39b3 introduced test-qga, and at face value, appears >> > to be testing the 'guest-sync' behavior that is recommended for >> > guests in sending 0xff to QGA to force the parser to reset. But >> > this aspect of the test has never actually done anything: the >> > qmp_fd() call chain converts its string argument into QObject, >> > then converts that QObject back to the actual string that is >> > sent over the wire - and the conversion process silently drops >> > the 0xff byte from the string sent to QGA, thus never resetting >> > the QGA parser. >> > >> > An upcoming patch will get rid of the wasteful round trip >> > through QObject, at which point the string in test-qga will be >> > directly sent over the wire. >> > >> > But fixing qmp_fd() to actually send 0xff over the wire is not >> > all we have to do - the actual QMP parser loudly complains that >> > 0xff is not valid JSON, and sends an error message _prior_ to >> > actually parsing the 'guest-sync' or 'guest-sync-delimited' >> > command. With 'guest-sync', we cannot easily tell if this error >> > message is a result of our command - which is WHY we invented >> > the 'guest-sync-delimited' command. So for the testsuite, fix >> > things to only check 0xff behavior on 'guest-sync-delimited', >> > and to loop until we've consumed all garbage prior to the >> > requested delimiter, which matches the documented actions that >> > a real QGA client is supposed to do. >> >> The full re-sync sequence is actually to perform that process, >> check if the response matches the client-provided sync token, >> and then repeat the procedure if it doesn't (in the odd case >> that a previous client initiated a guest-sync-delimited >> sequence and never consumed the response). The current >> implementation only performs one iteration so it's not quite >> a full implementation of the documentation procedure. > > Well, to be more accurate it's a full implementation of the > documented procedure, it's just that the procedure isn't > fully documented properly. I'll send a patch to address that.
Good. >> For the immediate purpose of improving the handling to deal >> with the 0xFF-generated error the patch seems sound though, >> maybe just something worth noting in the commit msg or >> comments so that we might eventually test the full procedure. Feel free to suggest something for me to add to the commit message. >> In any case: >> >> Reviewed-by: Michael Roth <mdr...@linux.vnet.ibm.com> Noted, thanks!
