From 62ef3760d4e400849fc663474227bb4668244455 Mon Sep 17 00:00:00 2001 From: Michael Roth Date: Thu, 17 Nov 2016 19:40:27 -0600 Subject: [PATCH] spapr: migration support for CAS-negotiated option vectors With the additional of the OV5_HP_EVT option vector, we now have certain functionality (namely, memory unplug) that checks at run-time for whether or not the guest negotiated the option via CAS. Because we don't currently migrate these negotiated values, we are unable to unplug memory from a guest after it's been migrated until after the guest is rebooted and CAS-negotiation is repeated. This patch fixes this by adding CAS-negotiated options to the migration stream. We do this using a subsection, since the negotiated value of OV5_HP_EVT is the only option currently needed to maintain proper functionality for a running guest. Signed-off-by: Michael Roth Signed-off-by: David Gibson --- hw/ppc/spapr.c | 66 +++++++++++++++++++++++++++++++++++++ hw/ppc/spapr_ovec.c | 12 +++++++ include/hw/ppc/spapr_ovec.h | 4 +++ 3 files changed, 82 insertions(+) diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 0cbab24c91..54b88d3f94 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -1267,6 +1267,68 @@ static bool version_before_3(void *opaque, int version_id) return version_id < 3; } +static bool spapr_ov5_cas_needed(void *opaque) +{ + sPAPRMachineState *spapr = opaque; + sPAPROptionVector *ov5_mask = spapr_ovec_new(); + sPAPROptionVector *ov5_legacy = spapr_ovec_new(); + sPAPROptionVector *ov5_removed = spapr_ovec_new(); + bool cas_needed; + + /* Prior to the introduction of sPAPROptionVector, we had two option + * vectors we dealt with: OV5_FORM1_AFFINITY, and OV5_DRCONF_MEMORY. + * Both of these options encode machine topology into the device-tree + * in such a way that the now-booted OS should still be able to interact + * appropriately with QEMU regardless of what options were actually + * negotiatied on the source side. + * + * As such, we can avoid migrating the CAS-negotiated options if these + * are the only options available on the current machine/platform. + * Since these are the only options available for pseries-2.7 and + * earlier, this allows us to maintain old->new/new->old migration + * compatibility. + * + * For QEMU 2.8+, there are additional CAS-negotiatable options available + * via default pseries-2.8 machines and explicit command-line parameters. + * Some of these options, like OV5_HP_EVT, *do* require QEMU to be aware + * of the actual CAS-negotiated values to continue working properly. For + * example, availability of memory unplug depends on knowing whether + * OV5_HP_EVT was negotiated via CAS. + * + * Thus, for any cases where the set of available CAS-negotiatable + * options extends beyond OV5_FORM1_AFFINITY and OV5_DRCONF_MEMORY, we + * include the CAS-negotiated options in the migration stream. + */ + spapr_ovec_set(ov5_mask, OV5_FORM1_AFFINITY); + spapr_ovec_set(ov5_mask, OV5_DRCONF_MEMORY); + + /* spapr_ovec_diff returns true if bits were removed. we avoid using + * the mask itself since in the future it's possible "legacy" bits may be + * removed via machine options, which could generate a false positive + * that breaks migration. + */ + spapr_ovec_intersect(ov5_legacy, spapr->ov5, ov5_mask); + cas_needed = spapr_ovec_diff(ov5_removed, spapr->ov5, ov5_legacy); + + spapr_ovec_cleanup(ov5_mask); + spapr_ovec_cleanup(ov5_legacy); + spapr_ovec_cleanup(ov5_removed); + + return cas_needed; +} + +static const VMStateDescription vmstate_spapr_ov5_cas = { + .name = "spapr_option_vector_ov5_cas", + .version_id = 1, + .minimum_version_id = 1, + .needed = spapr_ov5_cas_needed, + .fields = (VMStateField[]) { + VMSTATE_STRUCT_POINTER_V(ov5_cas, sPAPRMachineState, 1, + vmstate_spapr_ovec, sPAPROptionVector), + VMSTATE_END_OF_LIST() + }, +}; + static const VMStateDescription vmstate_spapr = { .name = "spapr", .version_id = 3, @@ -1282,6 +1344,10 @@ static const VMStateDescription vmstate_spapr = { VMSTATE_PPC_TIMEBASE_V(tb, sPAPRMachineState, 2), VMSTATE_END_OF_LIST() }, + .subsections = (const VMStateDescription*[]) { + &vmstate_spapr_ov5_cas, + NULL + } }; static int htab_save_setup(QEMUFile *f, void *opaque) diff --git a/hw/ppc/spapr_ovec.c b/hw/ppc/spapr_ovec.c index c2a0d18577..3eb1d5976f 100644 --- a/hw/ppc/spapr_ovec.c +++ b/hw/ppc/spapr_ovec.c @@ -37,6 +37,17 @@ */ struct sPAPROptionVector { unsigned long *bitmap; + int32_t bitmap_size; /* only used for migration */ +}; + +const VMStateDescription vmstate_spapr_ovec = { + .name = "spapr_option_vector", + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_BITMAP(bitmap, sPAPROptionVector, 1, bitmap_size), + VMSTATE_END_OF_LIST() + } }; sPAPROptionVector *spapr_ovec_new(void) @@ -45,6 +56,7 @@ sPAPROptionVector *spapr_ovec_new(void) ov = g_new0(sPAPROptionVector, 1); ov->bitmap = bitmap_new(OV_MAXBITS); + ov->bitmap_size = OV_MAXBITS; return ov; } diff --git a/include/hw/ppc/spapr_ovec.h b/include/hw/ppc/spapr_ovec.h index 6a06da32e6..355a34411f 100644 --- a/include/hw/ppc/spapr_ovec.h +++ b/include/hw/ppc/spapr_ovec.h @@ -37,6 +37,7 @@ #define _SPAPR_OVEC_H #include "cpu.h" +#include "migration/vmstate.h" typedef struct sPAPROptionVector sPAPROptionVector; @@ -64,4 +65,7 @@ sPAPROptionVector *spapr_ovec_parse_vector(target_ulong table_addr, int vector); int spapr_ovec_populate_dt(void *fdt, int fdt_offset, sPAPROptionVector *ov, const char *name); +/* migration */ +extern const VMStateDescription vmstate_spapr_ovec; + #endif /* !defined (_SPAPR_OVEC_H) */