Commit 62ef3760 authored by Michael Roth's avatar Michael Roth Committed by David Gibson
Browse files

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: default avatarMichael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent 171da9d5

hw/ppc/spapr.c

+66 −0
Original line number Diff line number Diff line
@@ -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)

hw/ppc/spapr_ovec.c

+12 −0
Original line number Diff line number Diff line
@@ -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;

}

include/hw/ppc/spapr_ovec.h

+4 −0
Original line number Diff line number Diff line
@@ -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) */