From: "Dr. David Alan Gilbert" <dgilb...@redhat.com> xbzrle relies on reading pages that have already been sent to the destination and then applying the modifications; we can't do that in postcopy because the destination may well have modified the page already or the page has been discarded.
I already didn't allow reception of xbzrle pages, but I forgot to add the test to stop them being sent. Enabling both xbzrle and postcopy can make some sense; if you think that your migration might finish if you have xbzrle, then when it doesn't complete you flick over to postcopy and stop xbzrle'ing. This corresponds to RH bug: https://bugzilla.redhat.com/show_bug.cgi?id=1368422 Symptom is: Unknown combination of migration flags: 0x60 (postcopy mode) (either 0x60 or 0x40) Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com> Reviewed-by: Juan Quintela <quint...@redhat.com> Signed-off-by: Juan Quintela <quint...@redhat.com> --- migration/ram.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/migration/ram.c b/migration/ram.c index c8ec9f2..bc6154f 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -771,7 +771,9 @@ static int ram_save_page(QEMUFile *f, PageSearchStatus *pss, * page would be stale */ xbzrle_cache_zero_page(current_addr); - } else if (!ram_bulk_stage && migrate_use_xbzrle()) { + } else if (!ram_bulk_stage && + !migration_in_postcopy(migrate_get_current()) && + migrate_use_xbzrle()) { pages = save_xbzrle_page(f, &p, current_addr, block, offset, last_stage, bytes_transferred); if (!last_stage) { -- 2.7.4
