From 146c11f16f12dbfea62cbd7f865614bb6fcbc6b5 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Mon, 21 Nov 2016 16:29:30 +1100 Subject: [PATCH] target-ppc: Allow eventual removal of old migration mistakes Until very recently, the vmstate for ppc cpus included some poorly thought out VMSTATE_EQUAL() components, that can easily break migration compatibility, and did so between qemu-2.6 and later versions. A hack was recently added which fixes this migration breakage, but it leaves the unhelpful cruft of these fields in the migration stream. This patch adds a new cpu property allowing these fields to be removed from the stream entirely. For the pseries-2.8 machine type - which comes after the fix - and for all non-pseries machine types - which aren't mature enough to care about cross-version migration - we remove the fields from the stream. For pseries-2.7 and earlier, The migration hack remains in place, allowing backwards and forwards migration with the older machine types. This restricts the migration compatibility cruft to older machine types, and at least opens the possibility of eventually deprecating and removing it entirely. Signed-off-by: David Gibson Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Thomas Huth Reviewed-by: Greg Kurz Reviewed-by: Alexey Kardashevskiy --- hw/ppc/spapr.c | 5 +++++ target-ppc/cpu.h | 3 ++- target-ppc/machine.c | 26 ++++++++++++++++++-------- target-ppc/translate_init.c | 6 ++++++ 4 files changed, 31 insertions(+), 9 deletions(-) diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 54b88d3f94..775ad2e1d9 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -2767,6 +2767,11 @@ DEFINE_SPAPR_MACHINE(2_8, "2.8", true); .driver = TYPE_SPAPR_PCI_HOST_BRIDGE, \ .property = "mem64_win_size", \ .value = "0", \ + }, \ + { \ + .driver = TYPE_POWERPC_CPU, \ + .property = "pre-2.8-migration", \ + .value = "on", \ }, static void phb_placement_2_7(sPAPRMachineState *spapr, uint32_t index, diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h index 7798b2ec23..2a50c43689 100644 --- a/target-ppc/cpu.h +++ b/target-ppc/cpu.h @@ -1167,7 +1167,8 @@ struct PowerPCCPU { uint32_t max_compat; uint32_t cpu_version; - /* fields used only during migration for compatibility hacks */ + /* Fields related to migration compatibility hacks */ + bool pre_2_8_migration; target_ulong mig_msr_mask; uint64_t mig_insns_flags; uint64_t mig_insns_flags2; diff --git a/target-ppc/machine.c b/target-ppc/machine.c index fcac263c7d..18c16d2512 100644 --- a/target-ppc/machine.c +++ b/target-ppc/machine.c @@ -135,6 +135,13 @@ static const VMStateInfo vmstate_info_avr = { #define VMSTATE_AVR_ARRAY(_f, _s, _n) \ VMSTATE_AVR_ARRAY_V(_f, _s, _n, 0) +static bool cpu_pre_2_8_migration(void *opaque, int version_id) +{ + PowerPCCPU *cpu = opaque; + + return cpu->pre_2_8_migration; +} + static void cpu_pre_save(void *opaque) { PowerPCCPU *cpu = opaque; @@ -178,10 +185,12 @@ static void cpu_pre_save(void *opaque) } /* Hacks for migration compatibility between 2.6, 2.7 & 2.8 */ - cpu->mig_msr_mask = env->msr_mask; - cpu->mig_insns_flags = env->insns_flags & insns_compat_mask; - cpu->mig_insns_flags2 = env->insns_flags2 & insns_compat_mask2; - cpu->mig_nb_BATs = env->nb_BATs; + if (cpu->pre_2_8_migration) { + cpu->mig_msr_mask = env->msr_mask; + cpu->mig_insns_flags = env->insns_flags & insns_compat_mask; + cpu->mig_insns_flags2 = env->insns_flags2 & insns_compat_mask2; + cpu->mig_nb_BATs = env->nb_BATs; + } } static int cpu_post_load(void *opaque, int version_id) @@ -582,10 +591,11 @@ const VMStateDescription vmstate_ppc_cpu = { /* FIXME: access_type? */ /* Sanity checking */ - VMSTATE_UINTTL(mig_msr_mask, PowerPCCPU), - VMSTATE_UINT64(mig_insns_flags, PowerPCCPU), - VMSTATE_UINT64(mig_insns_flags2, PowerPCCPU), - VMSTATE_UINT32(mig_nb_BATs, PowerPCCPU), + VMSTATE_UINTTL_TEST(mig_msr_mask, PowerPCCPU, cpu_pre_2_8_migration), + VMSTATE_UINT64_TEST(mig_insns_flags, PowerPCCPU, cpu_pre_2_8_migration), + VMSTATE_UINT64_TEST(mig_insns_flags2, PowerPCCPU, + cpu_pre_2_8_migration), + VMSTATE_UINT32_TEST(mig_nb_BATs, PowerPCCPU, cpu_pre_2_8_migration), VMSTATE_END_OF_LIST() }, .subsections = (const VMStateDescription*[]) { diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c index 208fa1ea53..626e03186c 100644 --- a/target-ppc/translate_init.c +++ b/target-ppc/translate_init.c @@ -10520,6 +10520,11 @@ static gchar *ppc_gdb_arch_name(CPUState *cs) #endif } +static Property ppc_cpu_properties[] = { + DEFINE_PROP_BOOL("pre-2.8-migration", PowerPCCPU, pre_2_8_migration, false), + DEFINE_PROP_END_OF_LIST(), +}; + static void ppc_cpu_class_init(ObjectClass *oc, void *data) { PowerPCCPUClass *pcc = POWERPC_CPU_CLASS(oc); @@ -10532,6 +10537,7 @@ static void ppc_cpu_class_init(ObjectClass *oc, void *data) pcc->interrupts_big_endian = ppc_cpu_interrupts_big_endian_always; dc->realize = ppc_cpu_realizefn; dc->unrealize = ppc_cpu_unrealizefn; + dc->props = ppc_cpu_properties; pcc->parent_reset = cc->reset; cc->reset = ppc_cpu_reset;