On Wed, 29 May 2019 11:10:57 +0530
Aravinda Prasad <aravi...@linux.vnet.ibm.com> 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 (i) these errors are specific to the source
> hardware and is irrelevant on the target hardware,
> (ii) these errors cause data corruption and should
> be handled before migration.
>
> Signed-off-by: Aravinda Prasad <aravi...@linux.vnet.ibm.com>
> ---
LGTM, just one issue: machine reset should del and free the blocker as well,
otherwise QEMU would crash if spapr_mce_req_event() is called again.
> hw/ppc/spapr.c | 20 ++++++++++++++++++++
> hw/ppc/spapr_events.c | 17 +++++++++++++++++
> hw/ppc/spapr_rtas.c | 4 ++++
> include/hw/ppc/spapr.h | 2 ++
> 4 files changed, 43 insertions(+)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index e8a77636..31c4850 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2104,6 +2104,25 @@ static const VMStateDescription vmstate_spapr_dtb = {
> },
> };
>
> +static bool spapr_fwnmi_needed(void *opaque)
> +{
> + SpaprMachineState *spapr = (SpaprMachineState *)opaque;
> +
> + return (spapr->guest_machine_check_addr == -1) ? 0 : 1;
> +}
> +
> +static const VMStateDescription vmstate_spapr_machine_check = {
> + .name = "spapr_machine_check",
> + .version_id = 1,
> + .minimum_version_id = 1,
> + .needed = spapr_fwnmi_needed,
> + .fields = (VMStateField[]) {
> + VMSTATE_UINT64(guest_machine_check_addr, SpaprMachineState),
> + VMSTATE_INT32(mc_status, SpaprMachineState),
> + VMSTATE_END_OF_LIST()
> + },
> +};
> +
> static const VMStateDescription vmstate_spapr = {
> .name = "spapr",
> .version_id = 3,
> @@ -2137,6 +2156,7 @@ static const VMStateDescription vmstate_spapr = {
> &vmstate_spapr_dtb,
> &vmstate_spapr_cap_large_decr,
> &vmstate_spapr_cap_ccf_assist,
> + &vmstate_spapr_machine_check,
> NULL
> }
> };
> diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
> index 573c0b7..35e21e4 100644
> --- a/hw/ppc/spapr_events.c
> +++ b/hw/ppc/spapr_events.c
> @@ -41,6 +41,7 @@
> #include "qemu/bcd.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
> @@ -855,6 +856,22 @@ static void spapr_mce_dispatch_elog(PowerPCCPU *cpu,
> bool recovered)
> void spapr_mce_req_event(PowerPCCPU *cpu, bool recovered)
> {
> SpaprMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());
> + int ret;
> + Error *local_err = NULL;
> +
> + error_setg(&spapr->fwnmi_migration_blocker,
> + "Live migration not supported during machine check handling");
> + ret = migrate_add_blocker(spapr->fwnmi_migration_blocker, &local_err);
> + if (ret < 0) {
> + /*
> + * We don't want to abort and let the migration to continue. In a
> + * rare case, the machine check handler will run on the target
> + * hardware. Though this is not preferable, it is better than
> aborting
> + * the migration or killing the VM.
> + */
> + error_free(spapr->fwnmi_migration_blocker);
> + warn_report_err(local_err);
> + }
>
> while (spapr->mc_status != -1) {
> /*
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index 91a7ab9..c849223 100644
> --- a/hw/ppc/spapr_rtas.c
> +++ b/hw/ppc/spapr_rtas.c
> @@ -50,6 +50,7 @@
> #include "target/ppc/mmu-hash64.h"
> #include "target/ppc/mmu-book3s-v3.h"
> #include "kvm_ppc.h"
> +#include "migration/blocker.h"
>
> static void rtas_display_character(PowerPCCPU *cpu, SpaprMachineState *spapr,
> uint32_t token, uint32_t nargs,
> @@ -404,6 +405,9 @@ static void rtas_ibm_nmi_interlock(PowerPCCPU *cpu,
> spapr->mc_status = -1;
> qemu_cond_signal(&spapr->mc_delivery_cond);
> rtas_st(rets, 0, RTAS_OUT_SUCCESS);
> + migrate_del_blocker(spapr->fwnmi_migration_blocker);
> + error_free(spapr->fwnmi_migration_blocker);
> + spapr->fwnmi_migration_blocker = NULL;
> }
> }
>
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index bd75d4b..6c0cfd8 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -214,6 +214,8 @@ struct SpaprMachineState {
> SpaprCapabilities def, eff, mig;
>
> unsigned gpu_numa_id;
> +
> + Error *fwnmi_migration_blocker;
> };
>
> #define H_SUCCESS 0
>
>
