qemu/migration/options.c

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/*
* QEMU migration capabilities
*
* Copyright (c) 2012-2023 Red Hat Inc
*
* Authors:
* Orit Wasserman <owasserm@redhat.com>
* Juan Quintela <quintela@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-migration.h"
#include "qapi/qmp/qerror.h"
#include "sysemu/runstate.h"
#include "migration.h"
#include "ram.h"
#include "options.h"
bool migrate_auto_converge(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
}
bool migrate_background_snapshot(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT];
}
bool migrate_block(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_BLOCK];
}
bool migrate_colo(void)
{
MigrationState *s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_X_COLO];
}
bool migrate_compress(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_COMPRESS];
}
bool migrate_dirty_bitmaps(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_DIRTY_BITMAPS];
}
bool migrate_events(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_EVENTS];
}
bool migrate_ignore_shared(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_X_IGNORE_SHARED];
}
bool migrate_late_block_activate(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE];
}
bool migrate_multifd(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_MULTIFD];
}
bool migrate_pause_before_switchover(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER];
}
bool migrate_postcopy_blocktime(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME];
}
bool migrate_postcopy_preempt(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_POSTCOPY_PREEMPT];
}
bool migrate_postcopy_ram(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM];
}
bool migrate_rdma_pin_all(void)
{
MigrationState *s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_RDMA_PIN_ALL];
}
bool migrate_release_ram(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_RELEASE_RAM];
}
bool migrate_return_path(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_RETURN_PATH];
}
bool migrate_validate_uuid(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_VALIDATE_UUID];
}
bool migrate_xbzrle(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_XBZRLE];
}
bool migrate_zero_blocks(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
}
bool migrate_zero_copy_send(void)
{
MigrationState *s;
s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_ZERO_COPY_SEND];
}
typedef enum WriteTrackingSupport {
WT_SUPPORT_UNKNOWN = 0,
WT_SUPPORT_ABSENT,
WT_SUPPORT_AVAILABLE,
WT_SUPPORT_COMPATIBLE
} WriteTrackingSupport;
static
WriteTrackingSupport migrate_query_write_tracking(void)
{
/* Check if kernel supports required UFFD features */
if (!ram_write_tracking_available()) {
return WT_SUPPORT_ABSENT;
}
/*
* Check if current memory configuration is
* compatible with required UFFD features.
*/
if (!ram_write_tracking_compatible()) {
return WT_SUPPORT_AVAILABLE;
}
return WT_SUPPORT_COMPATIBLE;
}
/* Migration capabilities set */
struct MigrateCapsSet {
int size; /* Capability set size */
MigrationCapability caps[]; /* Variadic array of capabilities */
};
typedef struct MigrateCapsSet MigrateCapsSet;
/* Define and initialize MigrateCapsSet */
#define INITIALIZE_MIGRATE_CAPS_SET(_name, ...) \
MigrateCapsSet _name = { \
.size = sizeof((int []) { __VA_ARGS__ }) / sizeof(int), \
.caps = { __VA_ARGS__ } \
}
/* Background-snapshot compatibility check list */
static const
INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot,
MIGRATION_CAPABILITY_POSTCOPY_RAM,
MIGRATION_CAPABILITY_DIRTY_BITMAPS,
MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME,
MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE,
MIGRATION_CAPABILITY_RETURN_PATH,
MIGRATION_CAPABILITY_MULTIFD,
MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER,
MIGRATION_CAPABILITY_AUTO_CONVERGE,
MIGRATION_CAPABILITY_RELEASE_RAM,
MIGRATION_CAPABILITY_RDMA_PIN_ALL,
MIGRATION_CAPABILITY_COMPRESS,
MIGRATION_CAPABILITY_XBZRLE,
MIGRATION_CAPABILITY_X_COLO,
MIGRATION_CAPABILITY_VALIDATE_UUID,
MIGRATION_CAPABILITY_ZERO_COPY_SEND);
/**
* @migration_caps_check - check capability compatibility
*
* @old_caps: old capability list
* @new_caps: new capability list
* @errp: set *errp if the check failed, with reason
*
* Returns true if check passed, otherwise false.
*/
bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp)
{
MigrationIncomingState *mis = migration_incoming_get_current();
#ifndef CONFIG_LIVE_BLOCK_MIGRATION
if (new_caps[MIGRATION_CAPABILITY_BLOCK]) {
error_setg(errp, "QEMU compiled without old-style (blk/-b, inc/-i) "
"block migration");
error_append_hint(errp, "Use drive_mirror+NBD instead.\n");
return false;
}
#endif
#ifndef CONFIG_REPLICATION
if (new_caps[MIGRATION_CAPABILITY_X_COLO]) {
error_setg(errp, "QEMU compiled without replication module"
" can't enable COLO");
error_append_hint(errp, "Please enable replication before COLO.\n");
return false;
}
#endif
if (new_caps[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
/* This check is reasonably expensive, so only when it's being
* set the first time, also it's only the destination that needs
* special support.
*/
if (!old_caps[MIGRATION_CAPABILITY_POSTCOPY_RAM] &&
runstate_check(RUN_STATE_INMIGRATE) &&
!postcopy_ram_supported_by_host(mis)) {
/* postcopy_ram_supported_by_host will have emitted a more
* detailed message
*/
error_setg(errp, "Postcopy is not supported");
return false;
}
if (new_caps[MIGRATION_CAPABILITY_X_IGNORE_SHARED]) {
error_setg(errp, "Postcopy is not compatible with ignore-shared");
return false;
}
}
if (new_caps[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT]) {
WriteTrackingSupport wt_support;
int idx;
/*
* Check if 'background-snapshot' capability is supported by
* host kernel and compatible with guest memory configuration.
*/
wt_support = migrate_query_write_tracking();
if (wt_support < WT_SUPPORT_AVAILABLE) {
error_setg(errp, "Background-snapshot is not supported by host kernel");
return false;
}
if (wt_support < WT_SUPPORT_COMPATIBLE) {
error_setg(errp, "Background-snapshot is not compatible "
"with guest memory configuration");
return false;
}
/*
* Check if there are any migration capabilities
* incompatible with 'background-snapshot'.
*/
for (idx = 0; idx < check_caps_background_snapshot.size; idx++) {
int incomp_cap = check_caps_background_snapshot.caps[idx];
if (new_caps[incomp_cap]) {
error_setg(errp,
"Background-snapshot is not compatible with %s",
MigrationCapability_str(incomp_cap));
return false;
}
}
}
#ifdef CONFIG_LINUX
if (new_caps[MIGRATION_CAPABILITY_ZERO_COPY_SEND] &&
(!new_caps[MIGRATION_CAPABILITY_MULTIFD] ||
new_caps[MIGRATION_CAPABILITY_COMPRESS] ||
new_caps[MIGRATION_CAPABILITY_XBZRLE] ||
migrate_multifd_compression() ||
migrate_use_tls())) {
error_setg(errp,
"Zero copy only available for non-compressed non-TLS multifd migration");
return false;
}
#else
if (new_caps[MIGRATION_CAPABILITY_ZERO_COPY_SEND]) {
error_setg(errp,
"Zero copy currently only available on Linux");
return false;
}
#endif
if (new_caps[MIGRATION_CAPABILITY_POSTCOPY_PREEMPT]) {
if (!new_caps[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
error_setg(errp, "Postcopy preempt requires postcopy-ram");
return false;
}
/*
* Preempt mode requires urgent pages to be sent in separate
* channel, OTOH compression logic will disorder all pages into
* different compression channels, which is not compatible with the
* preempt assumptions on channel assignments.
*/
if (new_caps[MIGRATION_CAPABILITY_COMPRESS]) {
error_setg(errp, "Postcopy preempt not compatible with compress");
return false;
}
}
if (new_caps[MIGRATION_CAPABILITY_MULTIFD]) {
if (new_caps[MIGRATION_CAPABILITY_COMPRESS]) {
error_setg(errp, "Multifd is not compatible with compress");
return false;
}
}
return true;
}
bool migrate_cap_set(int cap, bool value, Error **errp)
{
MigrationState *s = migrate_get_current();
bool new_caps[MIGRATION_CAPABILITY__MAX];
if (migration_is_running(s->state)) {
error_setg(errp, QERR_MIGRATION_ACTIVE);
return false;
}
memcpy(new_caps, s->capabilities, sizeof(new_caps));
new_caps[cap] = value;
if (!migrate_caps_check(s->capabilities, new_caps, errp)) {
return false;
}
s->capabilities[cap] = value;
return true;
}
MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
{
MigrationCapabilityStatusList *head = NULL, **tail = &head;
MigrationCapabilityStatus *caps;
MigrationState *s = migrate_get_current();
int i;
for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
#ifndef CONFIG_LIVE_BLOCK_MIGRATION
if (i == MIGRATION_CAPABILITY_BLOCK) {
continue;
}
#endif
caps = g_malloc0(sizeof(*caps));
caps->capability = i;
caps->state = s->capabilities[i];
QAPI_LIST_APPEND(tail, caps);
}
return head;
}
void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
Error **errp)
{
MigrationState *s = migrate_get_current();
MigrationCapabilityStatusList *cap;
bool new_caps[MIGRATION_CAPABILITY__MAX];
if (migration_is_running(s->state)) {
error_setg(errp, QERR_MIGRATION_ACTIVE);
return;
}
memcpy(new_caps, s->capabilities, sizeof(new_caps));
for (cap = params; cap; cap = cap->next) {
new_caps[cap->value->capability] = cap->value->state;
}
if (!migrate_caps_check(s->capabilities, new_caps, errp)) {
return;
}
for (cap = params; cap; cap = cap->next) {
s->capabilities[cap->value->capability] = cap->value->state;
}
}