On Wednesday 25 September 2019 07:09 AM, David Gibson wrote:
> On Wed, Sep 18, 2019 at 01:42:51PM +0530, Aravinda Prasad wrote:
>> This patch includes migration support for machine check
>> handling. Especially this patch blocks VM migration
>> requests until the machine check error handling is
>> complete as these errors are specific to the source
>> hardware and is irrelevant on the target hardware.
>>
>> Signed-off-by: Aravinda Prasad <aravi...@linux.vnet.ibm.com>
>> ---
>> hw/ppc/spapr.c | 63
>> ++++++++++++++++++++++++++++++++++++++++++++++++
>> hw/ppc/spapr_events.c | 16 +++++++++++-
>> hw/ppc/spapr_rtas.c | 2 ++
>> include/hw/ppc/spapr.h | 2 ++
>> 4 files changed, 82 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>> index 6992b32..a72a4b1 100644
>> --- a/hw/ppc/spapr.c
>> +++ b/hw/ppc/spapr.c
>> @@ -46,6 +46,7 @@
>> #include "migration/qemu-file-types.h"
>> #include "migration/global_state.h"
>> #include "migration/register.h"
>> +#include "migration/blocker.h"
>> #include "mmu-hash64.h"
>> #include "mmu-book3s-v3.h"
>> #include "cpu-models.h"
>> @@ -1829,6 +1830,8 @@ static void spapr_machine_reset(MachineState *machine)
>>
>> /* Signal all vCPUs waiting on this condition */
>> qemu_cond_broadcast(&spapr->mc_delivery_cond);
>> +
>> + migrate_del_blocker(spapr->fwnmi_migration_blocker);
>> }
>>
>> static void spapr_create_nvram(SpaprMachineState *spapr)
>> @@ -2119,6 +2122,60 @@ static const VMStateDescription vmstate_spapr_dtb = {
>> },
>> };
>>
>> +static bool spapr_fwnmi_needed(void *opaque)
>> +{
>> + SpaprMachineState *spapr = (SpaprMachineState *)opaque;
>> +
>> + return spapr->guest_machine_check_addr != -1;
>> +}
>> +
>> +static int spapr_fwnmi_post_load(void *opaque, int version_id)
>> +{
>> + SpaprMachineState *spapr = (SpaprMachineState *)opaque;
>> +
>> + if (spapr_get_cap(spapr, SPAPR_CAP_FWNMI_MCE) == SPAPR_CAP_ON) {
>> +
>> + if (kvmppc_has_cap_ppc_fwnmi()) {
>> + return 0;
>> + }
>> +
>> + return kvmppc_set_fwnmi();
>> + }
>
> I don't see that you need this. The spapr caps need to be set the
> same on source and destination (the caps infrastructure handles that),
> so setup should already be handled by the caps .apply hooks.
Will check.
>
>> +
>> + return 0;
>> +}
>> +
>> +static int spapr_fwnmi_pre_save(void *opaque)
>> +{
>> + SpaprMachineState *spapr = (SpaprMachineState *)opaque;
>> +
>> + /*
>> + * With -only-migratable QEMU option, we cannot block migration.
>> + * Hence check if machine check handling is in progress and print
>> + * a warning message.
>> + */
>> + if (spapr->mc_status != -1) {
>> + warn_report("A machine check is being handled during migration. The"
>> + "handler may run and log hardware error on the
>> destination");
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static const VMStateDescription vmstate_spapr_machine_check = {
>> + .name = "spapr_machine_check",
>> + .version_id = 1,
>> + .minimum_version_id = 1,
>> + .needed = spapr_fwnmi_needed,
>> + .post_load = spapr_fwnmi_post_load,
>> + .pre_save = spapr_fwnmi_pre_save,
>> + .fields = (VMStateField[]) {
>> + VMSTATE_UINT64(guest_machine_check_addr, SpaprMachineState),
>> + VMSTATE_INT32(mc_status, SpaprMachineState),
>> + VMSTATE_END_OF_LIST()
>> + },
>> +};
>
> So, I know I suggested earlier that you postpone the migration support
> to a later patch in the series. But at least for the actual vmstate
> stuff, I think that was due to considerations that have since gone. I
> don't see any reason you can't put this in as soon as you add the
> machine_check_addr and mc_status fields.
>
> The migration blocker stuff might have to come in a later patch, but
> that's ok.
I feel I can retain this. Let me know if you want me to change.
Regards,
Aravinda
>
>> +
>> static const VMStateDescription vmstate_spapr = {
>> .name = "spapr",
>> .version_id = 3,
>> @@ -2152,6 +2209,7 @@ static const VMStateDescription vmstate_spapr = {
>> &vmstate_spapr_dtb,
>> &vmstate_spapr_cap_large_decr,
>> &vmstate_spapr_cap_ccf_assist,
>> + &vmstate_spapr_machine_check,
>> NULL
>> }
>> };
>> @@ -2948,6 +3006,11 @@ static void spapr_machine_init(MachineState *machine)
>> exit(1);
>> }
>>
>> + /* Create the error string for live migration blocker */
>> + error_setg(&spapr->fwnmi_migration_blocker,
>> + "A machine check is being handled during migration. The handler"
>> + "may run and log hardware error on the destination");
>> +
>> /* Register ibm,nmi-register and ibm,nmi-interlock RTAS calls */
>> spapr_fwnmi_register();
>> }
>> diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
>> index ecc3d68..71caa03 100644
>> --- a/hw/ppc/spapr_events.c
>> +++ b/hw/ppc/spapr_events.c
>> @@ -43,6 +43,7 @@
>> #include "qemu/main-loop.h"
>> #include "hw/ppc/spapr_ovec.h"
>> #include <libfdt.h>
>> +#include "migration/blocker.h"
>>
>> #define RTAS_LOG_VERSION_MASK 0xff000000
>> #define RTAS_LOG_VERSION_6 0x06000000
>> @@ -844,6 +845,8 @@ void spapr_mce_req_event(PowerPCCPU *cpu, bool recovered)
>> {
>> SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
>> CPUState *cs = CPU(cpu);
>> + int ret;
>> + Error *local_err = NULL;
>>
>> if (spapr->guest_machine_check_addr == -1) {
>> /*
>> @@ -873,8 +876,19 @@ void spapr_mce_req_event(PowerPCCPU *cpu, bool
>> recovered)
>> return;
>> }
>> }
>> - spapr->mc_status = cpu->vcpu_id;
>>
>> + ret = migrate_add_blocker(spapr->fwnmi_migration_blocker, &local_err);
>> + if (ret == -EBUSY) {
>> + /*
>> + * We don't want to abort so we let the migration to continue.
>> + * In a rare case, the machine check handler will run on the target.
>> + * Though this is not preferable, it is better than aborting
>> + * the migration or killing the VM.
>> + */
>> + warn_report_err(local_err);
>> + }
>> +
>> + spapr->mc_status = cpu->vcpu_id;
>> spapr_mce_dispatch_elog(cpu, recovered);
>> }
>>
>> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
>> index b569538..c652ec3 100644
>> --- a/hw/ppc/spapr_rtas.c
>> +++ b/hw/ppc/spapr_rtas.c
>> @@ -50,6 +50,7 @@
>> #include "hw/ppc/fdt.h"
>> #include "target/ppc/mmu-hash64.h"
>> #include "target/ppc/mmu-book3s-v3.h"
>> +#include "migration/blocker.h"
>>
>> static void rtas_display_character(PowerPCCPU *cpu, SpaprMachineState
>> *spapr,
>> uint32_t token, uint32_t nargs,
>> @@ -446,6 +447,7 @@ static void rtas_ibm_nmi_interlock(PowerPCCPU *cpu,
>> */
>> spapr->mc_status = -1;
>> qemu_cond_signal(&spapr->mc_delivery_cond);
>> + migrate_del_blocker(spapr->fwnmi_migration_blocker);
>> rtas_st(rets, 0, RTAS_OUT_SUCCESS);
>> }
>>
>> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
>> index dada821..ea7625e 100644
>> --- a/include/hw/ppc/spapr.h
>> +++ b/include/hw/ppc/spapr.h
>> @@ -217,6 +217,8 @@ struct SpaprMachineState {
>>
>> unsigned gpu_numa_id;
>> SpaprTpmProxy *tpm_proxy;
>> +
>> + Error *fwnmi_migration_blocker;
>> };
>>
>> #define H_SUCCESS 0
>>
>
--
Regards,
Aravinda
