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 --- hw/ppc/spapr.c | 1 + hw/ppc/spapr_caps.c | 12 +++++++++++- 2 files changed, 12 insertions(+), 1 deletion(-) (limited to 'hw') diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 4fd16b43f0..e2b33e5890 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -4431,6 +4431,7 @@ static void spapr_machine_4_0_class_options(MachineClass *mc) compat_props_add(mc->compat_props, hw_compat_4_0, hw_compat_4_0_len); smc->phb_placement = phb_placement_4_0; smc->irq = &spapr_irq_xics; + smc->pre_4_1_migration = true; } DEFINE_SPAPR_MACHINE(4_0, "4.0", false); diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c index 658eb15a14..31b4661399 100644 --- a/hw/ppc/spapr_caps.c +++ b/hw/ppc/spapr_caps.c @@ -64,6 +64,7 @@ typedef struct SpaprCapabilityInfo { void (*apply)(SpaprMachineState *spapr, uint8_t val, Error **errp); void (*cpu_apply)(SpaprMachineState *spapr, PowerPCCPU *cpu, uint8_t val, Error **errp); + bool (*migrate_needed)(void *opaque); } SpaprCapabilityInfo; static void spapr_cap_get_bool(Object *obj, Visitor *v, const char *name, @@ -350,6 +351,11 @@ static void cap_hpt_maxpagesize_apply(SpaprMachineState *spapr, spapr_check_pagesize(spapr, qemu_minrampagesize(), errp); } +static bool cap_hpt_maxpagesize_migrate_needed(void *opaque) +{ + return !SPAPR_MACHINE_GET_CLASS(opaque)->pre_4_1_migration; +} + static bool spapr_pagesize_cb(void *opaque, uint32_t seg_pshift, uint32_t pshift) { @@ -542,6 +548,7 @@ SpaprCapabilityInfo capability_table[SPAPR_CAP_NUM] = { .type = "int", .apply = cap_hpt_maxpagesize_apply, .cpu_apply = cap_hpt_maxpagesize_cpu_apply, + .migrate_needed = cap_hpt_maxpagesize_migrate_needed, }, [SPAPR_CAP_NESTED_KVM_HV] = { .name = "nested-hv", @@ -679,8 +686,11 @@ int spapr_caps_post_migration(SpaprMachineState *spapr) static bool spapr_cap_##sname##_needed(void *opaque) \ { \ SpaprMachineState *spapr = opaque; \ + bool (*needed)(void *opaque) = \ + capability_table[cap].migrate_needed; \ \ - return spapr->cmd_line_caps[cap] && \ + return needed ? needed(opaque) : true && \ + spapr->cmd_line_caps[cap] && \ (spapr->eff.caps[cap] != \ spapr->def.caps[cap]); \ } \ -- cgit v1.2.3