From 3725ef1a944bbe1173b55fdabe76fb17876f1d9e Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Wed, 22 May 2019 15:43:46 +0200 Subject: spapr: Don't migrate the hpt_maxpagesize cap to older machine types Commit 0b8c89be7f7b added the hpt_maxpagesize capability to the migration stream. This is okay for new machine types but it breaks backward migration to older QEMUs, which don't expect the extra subsection. Add a compatibility boolean flag to the sPAPR machine class and use it to skip migration of the capability for machine types 4.0 and older. This fixes migration to an older QEMU. Note that the destination will emit a warning: qemu-system-ppc64: warning: cap-hpt-max-page-size lower level (16) in incoming stream than on destination (24) This is expected and harmless though. It is okay to migrate from a lower HPT maximum page size (64k) to a greater one (16M). Fixes: 0b8c89be7f7b "spapr: Add forgotten capability to migration stream" Based-on: <20190522074016.10521-3-clg@kaod.org> Signed-off-by: Greg Kurz Message-Id: <155853262675.1158324.17301777846476373459.stgit@bahia.lan> Signed-off-by: David Gibson --- include/hw/ppc/spapr.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h index 9fc91c8f5e..4f5becf1f3 100644 --- a/include/hw/ppc/spapr.h +++ b/include/hw/ppc/spapr.h @@ -119,6 +119,7 @@ struct SpaprMachineClass { bool pre_2_10_has_unused_icps; bool legacy_irq_allocation; bool broken_host_serial_model; /* present real host info to the guest */ + bool pre_4_1_migration; /* don't migrate hpt-max-page-size */ void (*phb_placement)(SpaprMachineState *spapr, uint32_t index, uint64_t *buid, hwaddr *pio, -- cgit v1.2.3-55-g7522