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Re: [Qemu-devel] [Qemu-ppc] [PATCH v8 6/6] migration: Block migration wh
From: |
Greg Kurz |
Subject: |
Re: [Qemu-devel] [Qemu-ppc] [PATCH v8 6/6] migration: Block migration while handling machine check |
Date: |
Thu, 16 May 2019 12:54:45 +0200 |
On Mon, 22 Apr 2019 12:33:45 +0530
Aravinda Prasad <address@hidden> wrote:
> Block 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 <address@hidden>
> ---
> hw/ppc/spapr_events.c | 17 +++++++++++++++++
> hw/ppc/spapr_rtas.c | 4 ++++
> include/hw/ppc/spapr.h | 3 +++
> 3 files changed, 24 insertions(+)
>
> diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
> index 4032db0..45b990c 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
> @@ -864,6 +865,22 @@ 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->migration_blocker,
> + "Live migration not supported during machine check handling");
> + ret = migrate_add_blocker(spapr->migration_blocker, &local_err);
migrate_add_blocker() propagates the reason of the failure in local_err,
ie. because a migration is already in progress or --only-migratable was
passed on the QEMU command line, along with the error message passed in
the first argument. This means that...
> + 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->migration_blocker);
> + fprintf(stderr, "Warning: Machine check during VM migration\n");
... you should just do:
error_report_err(local_err);
This also takes care of freeing local_err which would be leaked otherwise.
> + }
>
> while (spapr->mc_status != -1) {
> /*
> diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
> index 997cf19..1229a0e 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,
> @@ -396,6 +397,9 @@ 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->migration_blocker);
> + error_free(spapr->migration_blocker);
> + spapr->migration_blocker = NULL;
> }
> }
>
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 9d16ad1..dda5fd2 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -10,6 +10,7 @@
> #include "hw/ppc/spapr_irq.h"
> #include "hw/ppc/spapr_xive.h" /* For SpaprXive */
> #include "hw/ppc/xics.h" /* For ICSState */
> +#include "qapi/error.h"
>
> struct SpaprVioBus;
> struct SpaprPhbState;
> @@ -213,6 +214,8 @@ struct SpaprMachineState {
> SpaprCapabilities def, eff, mig;
>
> unsigned gpu_numa_id;
> +
> + Error *migration_blocker;
> };
>
> #define H_SUCCESS 0
>
>
- Re: [Qemu-devel] [Qemu-ppc] [PATCH v8 6/6] migration: Block migration while handling machine check,
Greg Kurz <=