2 * Postcopy migration for RAM
4 * Copyright 2013-2015 Red Hat, Inc. and/or its affiliates
7 * Dave Gilbert <dgilbert@redhat.com>
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
15 * Postcopy is a migration technique where the execution flips from the
16 * source to the destination before all the data has been copied.
19 #include "qemu/osdep.h"
20 #include "qemu/madvise.h"
21 #include "exec/target_page.h"
22 #include "migration.h"
23 #include "qemu-file.h"
25 #include "postcopy-ram.h"
27 #include "qapi/error.h"
28 #include "qemu/notify.h"
30 #include "sysemu/sysemu.h"
31 #include "qemu/error-report.h"
33 #include "hw/boards.h"
34 #include "exec/ramblock.h"
36 #include "yank_functions.h"
38 #include "qemu/userfaultfd.h"
40 /* Arbitrary limit on size of each discard command,
41 * keeps them around ~200 bytes
43 #define MAX_DISCARDS_PER_COMMAND 12
45 struct PostcopyDiscardState
{
46 const char *ramblock_name
;
49 * Start and length of a discard range (bytes)
51 uint64_t start_list
[MAX_DISCARDS_PER_COMMAND
];
52 uint64_t length_list
[MAX_DISCARDS_PER_COMMAND
];
53 unsigned int nsentwords
;
54 unsigned int nsentcmds
;
57 static NotifierWithReturnList postcopy_notifier_list
;
59 void postcopy_infrastructure_init(void)
61 notifier_with_return_list_init(&postcopy_notifier_list
);
64 void postcopy_add_notifier(NotifierWithReturn
*nn
)
66 notifier_with_return_list_add(&postcopy_notifier_list
, nn
);
69 void postcopy_remove_notifier(NotifierWithReturn
*n
)
71 notifier_with_return_remove(n
);
74 int postcopy_notify(enum PostcopyNotifyReason reason
, Error
**errp
)
76 struct PostcopyNotifyData pnd
;
80 return notifier_with_return_list_notify(&postcopy_notifier_list
,
85 * NOTE: this routine is not thread safe, we can't call it concurrently. But it
86 * should be good enough for migration's purposes.
88 void postcopy_thread_create(MigrationIncomingState
*mis
,
89 QemuThread
*thread
, const char *name
,
90 void *(*fn
)(void *), int joinable
)
92 qemu_sem_init(&mis
->thread_sync_sem
, 0);
93 qemu_thread_create(thread
, name
, fn
, mis
, joinable
);
94 qemu_sem_wait(&mis
->thread_sync_sem
);
95 qemu_sem_destroy(&mis
->thread_sync_sem
);
98 /* Postcopy needs to detect accesses to pages that haven't yet been copied
99 * across, and efficiently map new pages in, the techniques for doing this
100 * are target OS specific.
102 #if defined(__linux__)
105 #include <sys/ioctl.h>
106 #include <sys/syscall.h>
107 #include <asm/types.h> /* for __u64 */
110 #if defined(__linux__) && defined(__NR_userfaultfd) && defined(CONFIG_EVENTFD)
111 #include <sys/eventfd.h>
112 #include <linux/userfaultfd.h>
114 typedef struct PostcopyBlocktimeContext
{
115 /* time when page fault initiated per vCPU */
116 uint32_t *page_fault_vcpu_time
;
117 /* page address per vCPU */
118 uintptr_t *vcpu_addr
;
119 uint32_t total_blocktime
;
120 /* blocktime per vCPU */
121 uint32_t *vcpu_blocktime
;
122 /* point in time when last page fault was initiated */
124 /* number of vCPU are suspended */
129 * Handler for exit event, necessary for
130 * releasing whole blocktime_ctx
132 Notifier exit_notifier
;
133 } PostcopyBlocktimeContext
;
135 static void destroy_blocktime_context(struct PostcopyBlocktimeContext
*ctx
)
137 g_free(ctx
->page_fault_vcpu_time
);
138 g_free(ctx
->vcpu_addr
);
139 g_free(ctx
->vcpu_blocktime
);
143 static void migration_exit_cb(Notifier
*n
, void *data
)
145 PostcopyBlocktimeContext
*ctx
= container_of(n
, PostcopyBlocktimeContext
,
147 destroy_blocktime_context(ctx
);
150 static struct PostcopyBlocktimeContext
*blocktime_context_new(void)
152 MachineState
*ms
= MACHINE(qdev_get_machine());
153 unsigned int smp_cpus
= ms
->smp
.cpus
;
154 PostcopyBlocktimeContext
*ctx
= g_new0(PostcopyBlocktimeContext
, 1);
155 ctx
->page_fault_vcpu_time
= g_new0(uint32_t, smp_cpus
);
156 ctx
->vcpu_addr
= g_new0(uintptr_t, smp_cpus
);
157 ctx
->vcpu_blocktime
= g_new0(uint32_t, smp_cpus
);
159 ctx
->exit_notifier
.notify
= migration_exit_cb
;
160 ctx
->start_time
= qemu_clock_get_ms(QEMU_CLOCK_REALTIME
);
161 qemu_add_exit_notifier(&ctx
->exit_notifier
);
165 static uint32List
*get_vcpu_blocktime_list(PostcopyBlocktimeContext
*ctx
)
167 MachineState
*ms
= MACHINE(qdev_get_machine());
168 uint32List
*list
= NULL
;
171 for (i
= ms
->smp
.cpus
- 1; i
>= 0; i
--) {
172 QAPI_LIST_PREPEND(list
, ctx
->vcpu_blocktime
[i
]);
179 * This function just populates MigrationInfo from postcopy's
180 * blocktime context. It will not populate MigrationInfo,
181 * unless postcopy-blocktime capability was set.
183 * @info: pointer to MigrationInfo to populate
185 void fill_destination_postcopy_migration_info(MigrationInfo
*info
)
187 MigrationIncomingState
*mis
= migration_incoming_get_current();
188 PostcopyBlocktimeContext
*bc
= mis
->blocktime_ctx
;
194 info
->has_postcopy_blocktime
= true;
195 info
->postcopy_blocktime
= bc
->total_blocktime
;
196 info
->has_postcopy_vcpu_blocktime
= true;
197 info
->postcopy_vcpu_blocktime
= get_vcpu_blocktime_list(bc
);
200 static uint32_t get_postcopy_total_blocktime(void)
202 MigrationIncomingState
*mis
= migration_incoming_get_current();
203 PostcopyBlocktimeContext
*bc
= mis
->blocktime_ctx
;
209 return bc
->total_blocktime
;
213 * receive_ufd_features: check userfault fd features, to request only supported
214 * features in the future.
216 * Returns: true on success
218 * __NR_userfaultfd - should be checked before
219 * @features: out parameter will contain uffdio_api.features provided by kernel
222 static bool receive_ufd_features(uint64_t *features
)
224 struct uffdio_api api_struct
= {0};
228 ufd
= uffd_open(O_CLOEXEC
);
230 error_report("%s: uffd_open() failed: %s", __func__
, strerror(errno
));
235 api_struct
.api
= UFFD_API
;
236 api_struct
.features
= 0;
237 if (ioctl(ufd
, UFFDIO_API
, &api_struct
)) {
238 error_report("%s: UFFDIO_API failed: %s", __func__
,
244 *features
= api_struct
.features
;
252 * request_ufd_features: this function should be called only once on a newly
253 * opened ufd, subsequent calls will lead to error.
255 * Returns: true on success
257 * @ufd: fd obtained from userfaultfd syscall
258 * @features: bit mask see UFFD_API_FEATURES
260 static bool request_ufd_features(int ufd
, uint64_t features
)
262 struct uffdio_api api_struct
= {0};
265 api_struct
.api
= UFFD_API
;
266 api_struct
.features
= features
;
267 if (ioctl(ufd
, UFFDIO_API
, &api_struct
)) {
268 error_report("%s failed: UFFDIO_API failed: %s", __func__
,
273 ioctl_mask
= (__u64
)1 << _UFFDIO_REGISTER
|
274 (__u64
)1 << _UFFDIO_UNREGISTER
;
275 if ((api_struct
.ioctls
& ioctl_mask
) != ioctl_mask
) {
276 error_report("Missing userfault features: %" PRIx64
,
277 (uint64_t)(~api_struct
.ioctls
& ioctl_mask
));
284 static bool ufd_check_and_apply(int ufd
, MigrationIncomingState
*mis
)
286 uint64_t asked_features
= 0;
287 static uint64_t supported_features
;
290 * it's not possible to
291 * request UFFD_API twice per one fd
292 * userfault fd features is persistent
294 if (!supported_features
) {
295 if (!receive_ufd_features(&supported_features
)) {
296 error_report("%s failed", __func__
);
301 #ifdef UFFD_FEATURE_THREAD_ID
302 if (UFFD_FEATURE_THREAD_ID
& supported_features
) {
303 asked_features
|= UFFD_FEATURE_THREAD_ID
;
304 if (migrate_postcopy_blocktime()) {
305 if (!mis
->blocktime_ctx
) {
306 mis
->blocktime_ctx
= blocktime_context_new();
313 * request features, even if asked_features is 0, due to
314 * kernel expects UFFD_API before UFFDIO_REGISTER, per
315 * userfault file descriptor
317 if (!request_ufd_features(ufd
, asked_features
)) {
318 error_report("%s failed: features %" PRIu64
, __func__
,
323 if (qemu_real_host_page_size() != ram_pagesize_summary()) {
324 bool have_hp
= false;
325 /* We've got a huge page */
326 #ifdef UFFD_FEATURE_MISSING_HUGETLBFS
327 have_hp
= supported_features
& UFFD_FEATURE_MISSING_HUGETLBFS
;
330 error_report("Userfault on this host does not support huge pages");
337 /* Callback from postcopy_ram_supported_by_host block iterator.
339 static int test_ramblock_postcopiable(RAMBlock
*rb
, void *opaque
)
341 const char *block_name
= qemu_ram_get_idstr(rb
);
342 ram_addr_t length
= qemu_ram_get_used_length(rb
);
343 size_t pagesize
= qemu_ram_pagesize(rb
);
345 if (length
% pagesize
) {
346 error_report("Postcopy requires RAM blocks to be a page size multiple,"
347 " block %s is 0x" RAM_ADDR_FMT
" bytes with a "
348 "page size of 0x%zx", block_name
, length
, pagesize
);
355 * Note: This has the side effect of munlock'ing all of RAM, that's
356 * normally fine since if the postcopy succeeds it gets turned back on at the
359 bool postcopy_ram_supported_by_host(MigrationIncomingState
*mis
)
361 long pagesize
= qemu_real_host_page_size();
363 bool ret
= false; /* Error unless we change it */
364 void *testarea
= NULL
;
365 struct uffdio_register reg_struct
;
366 struct uffdio_range range_struct
;
367 uint64_t feature_mask
;
368 Error
*local_err
= NULL
;
370 if (qemu_target_page_size() > pagesize
) {
371 error_report("Target page size bigger than host page size");
375 ufd
= uffd_open(O_CLOEXEC
);
377 error_report("%s: userfaultfd not available: %s", __func__
,
382 /* Give devices a chance to object */
383 if (postcopy_notify(POSTCOPY_NOTIFY_PROBE
, &local_err
)) {
384 error_report_err(local_err
);
388 /* Version and features check */
389 if (!ufd_check_and_apply(ufd
, mis
)) {
393 /* We don't support postcopy with shared RAM yet */
394 if (foreach_not_ignored_block(test_ramblock_postcopiable
, NULL
)) {
399 * userfault and mlock don't go together; we'll put it back later if
403 error_report("%s: munlockall: %s", __func__
, strerror(errno
));
408 * We need to check that the ops we need are supported on anon memory
409 * To do that we need to register a chunk and see the flags that
412 testarea
= mmap(NULL
, pagesize
, PROT_READ
| PROT_WRITE
, MAP_PRIVATE
|
413 MAP_ANONYMOUS
, -1, 0);
414 if (testarea
== MAP_FAILED
) {
415 error_report("%s: Failed to map test area: %s", __func__
,
419 g_assert(QEMU_PTR_IS_ALIGNED(testarea
, pagesize
));
421 reg_struct
.range
.start
= (uintptr_t)testarea
;
422 reg_struct
.range
.len
= pagesize
;
423 reg_struct
.mode
= UFFDIO_REGISTER_MODE_MISSING
;
425 if (ioctl(ufd
, UFFDIO_REGISTER
, ®_struct
)) {
426 error_report("%s userfault register: %s", __func__
, strerror(errno
));
430 range_struct
.start
= (uintptr_t)testarea
;
431 range_struct
.len
= pagesize
;
432 if (ioctl(ufd
, UFFDIO_UNREGISTER
, &range_struct
)) {
433 error_report("%s userfault unregister: %s", __func__
, strerror(errno
));
437 feature_mask
= (__u64
)1 << _UFFDIO_WAKE
|
438 (__u64
)1 << _UFFDIO_COPY
|
439 (__u64
)1 << _UFFDIO_ZEROPAGE
;
440 if ((reg_struct
.ioctls
& feature_mask
) != feature_mask
) {
441 error_report("Missing userfault map features: %" PRIx64
,
442 (uint64_t)(~reg_struct
.ioctls
& feature_mask
));
450 munmap(testarea
, pagesize
);
459 * Setup an area of RAM so that it *can* be used for postcopy later; this
460 * must be done right at the start prior to pre-copy.
461 * opaque should be the MIS.
463 static int init_range(RAMBlock
*rb
, void *opaque
)
465 const char *block_name
= qemu_ram_get_idstr(rb
);
466 void *host_addr
= qemu_ram_get_host_addr(rb
);
467 ram_addr_t offset
= qemu_ram_get_offset(rb
);
468 ram_addr_t length
= qemu_ram_get_used_length(rb
);
469 trace_postcopy_init_range(block_name
, host_addr
, offset
, length
);
472 * Save the used_length before running the guest. In case we have to
473 * resize RAM blocks when syncing RAM block sizes from the source during
474 * precopy, we'll update it manually via the ram block notifier.
476 rb
->postcopy_length
= length
;
479 * We need the whole of RAM to be truly empty for postcopy, so things
480 * like ROMs and any data tables built during init must be zero'd
481 * - we're going to get the copy from the source anyway.
482 * (Precopy will just overwrite this data, so doesn't need the discard)
484 if (ram_discard_range(block_name
, 0, length
)) {
492 * At the end of migration, undo the effects of init_range
493 * opaque should be the MIS.
495 static int cleanup_range(RAMBlock
*rb
, void *opaque
)
497 const char *block_name
= qemu_ram_get_idstr(rb
);
498 void *host_addr
= qemu_ram_get_host_addr(rb
);
499 ram_addr_t offset
= qemu_ram_get_offset(rb
);
500 ram_addr_t length
= rb
->postcopy_length
;
501 MigrationIncomingState
*mis
= opaque
;
502 struct uffdio_range range_struct
;
503 trace_postcopy_cleanup_range(block_name
, host_addr
, offset
, length
);
506 * We turned off hugepage for the precopy stage with postcopy enabled
507 * we can turn it back on now.
509 qemu_madvise(host_addr
, length
, QEMU_MADV_HUGEPAGE
);
512 * We can also turn off userfault now since we should have all the
513 * pages. It can be useful to leave it on to debug postcopy
514 * if you're not sure it's always getting every page.
516 range_struct
.start
= (uintptr_t)host_addr
;
517 range_struct
.len
= length
;
519 if (ioctl(mis
->userfault_fd
, UFFDIO_UNREGISTER
, &range_struct
)) {
520 error_report("%s: userfault unregister %s", __func__
, strerror(errno
));
529 * Initialise postcopy-ram, setting the RAM to a state where we can go into
530 * postcopy later; must be called prior to any precopy.
531 * called from arch_init's similarly named ram_postcopy_incoming_init
533 int postcopy_ram_incoming_init(MigrationIncomingState
*mis
)
535 if (foreach_not_ignored_block(init_range
, NULL
)) {
542 static void postcopy_temp_pages_cleanup(MigrationIncomingState
*mis
)
546 if (mis
->postcopy_tmp_pages
) {
547 for (i
= 0; i
< mis
->postcopy_channels
; i
++) {
548 if (mis
->postcopy_tmp_pages
[i
].tmp_huge_page
) {
549 munmap(mis
->postcopy_tmp_pages
[i
].tmp_huge_page
,
550 mis
->largest_page_size
);
551 mis
->postcopy_tmp_pages
[i
].tmp_huge_page
= NULL
;
554 g_free(mis
->postcopy_tmp_pages
);
555 mis
->postcopy_tmp_pages
= NULL
;
558 if (mis
->postcopy_tmp_zero_page
) {
559 munmap(mis
->postcopy_tmp_zero_page
, mis
->largest_page_size
);
560 mis
->postcopy_tmp_zero_page
= NULL
;
565 * At the end of a migration where postcopy_ram_incoming_init was called.
567 int postcopy_ram_incoming_cleanup(MigrationIncomingState
*mis
)
569 trace_postcopy_ram_incoming_cleanup_entry();
571 if (mis
->postcopy_prio_thread_created
) {
572 qemu_thread_join(&mis
->postcopy_prio_thread
);
573 mis
->postcopy_prio_thread_created
= false;
576 if (mis
->have_fault_thread
) {
577 Error
*local_err
= NULL
;
579 /* Let the fault thread quit */
580 qatomic_set(&mis
->fault_thread_quit
, 1);
581 postcopy_fault_thread_notify(mis
);
582 trace_postcopy_ram_incoming_cleanup_join();
583 qemu_thread_join(&mis
->fault_thread
);
585 if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_END
, &local_err
)) {
586 error_report_err(local_err
);
590 if (foreach_not_ignored_block(cleanup_range
, mis
)) {
594 trace_postcopy_ram_incoming_cleanup_closeuf();
595 close(mis
->userfault_fd
);
596 close(mis
->userfault_event_fd
);
597 mis
->have_fault_thread
= false;
601 if (os_mlock() < 0) {
602 error_report("mlock: %s", strerror(errno
));
604 * It doesn't feel right to fail at this point, we have a valid
610 postcopy_temp_pages_cleanup(mis
);
612 trace_postcopy_ram_incoming_cleanup_blocktime(
613 get_postcopy_total_blocktime());
615 trace_postcopy_ram_incoming_cleanup_exit();
620 * Disable huge pages on an area
622 static int nhp_range(RAMBlock
*rb
, void *opaque
)
624 const char *block_name
= qemu_ram_get_idstr(rb
);
625 void *host_addr
= qemu_ram_get_host_addr(rb
);
626 ram_addr_t offset
= qemu_ram_get_offset(rb
);
627 ram_addr_t length
= rb
->postcopy_length
;
628 trace_postcopy_nhp_range(block_name
, host_addr
, offset
, length
);
631 * Before we do discards we need to ensure those discards really
632 * do delete areas of the page, even if THP thinks a hugepage would
633 * be a good idea, so force hugepages off.
635 qemu_madvise(host_addr
, length
, QEMU_MADV_NOHUGEPAGE
);
641 * Userfault requires us to mark RAM as NOHUGEPAGE prior to discard
642 * however leaving it until after precopy means that most of the precopy
645 int postcopy_ram_prepare_discard(MigrationIncomingState
*mis
)
647 if (foreach_not_ignored_block(nhp_range
, mis
)) {
651 postcopy_state_set(POSTCOPY_INCOMING_DISCARD
);
657 * Mark the given area of RAM as requiring notification to unwritten areas
658 * Used as a callback on foreach_not_ignored_block.
659 * host_addr: Base of area to mark
660 * offset: Offset in the whole ram arena
661 * length: Length of the section
662 * opaque: MigrationIncomingState pointer
663 * Returns 0 on success
665 static int ram_block_enable_notify(RAMBlock
*rb
, void *opaque
)
667 MigrationIncomingState
*mis
= opaque
;
668 struct uffdio_register reg_struct
;
670 reg_struct
.range
.start
= (uintptr_t)qemu_ram_get_host_addr(rb
);
671 reg_struct
.range
.len
= rb
->postcopy_length
;
672 reg_struct
.mode
= UFFDIO_REGISTER_MODE_MISSING
;
674 /* Now tell our userfault_fd that it's responsible for this area */
675 if (ioctl(mis
->userfault_fd
, UFFDIO_REGISTER
, ®_struct
)) {
676 error_report("%s userfault register: %s", __func__
, strerror(errno
));
679 if (!(reg_struct
.ioctls
& ((__u64
)1 << _UFFDIO_COPY
))) {
680 error_report("%s userfault: Region doesn't support COPY", __func__
);
683 if (reg_struct
.ioctls
& ((__u64
)1 << _UFFDIO_ZEROPAGE
)) {
684 qemu_ram_set_uf_zeroable(rb
);
690 int postcopy_wake_shared(struct PostCopyFD
*pcfd
,
691 uint64_t client_addr
,
694 size_t pagesize
= qemu_ram_pagesize(rb
);
695 struct uffdio_range range
;
697 trace_postcopy_wake_shared(client_addr
, qemu_ram_get_idstr(rb
));
698 range
.start
= ROUND_DOWN(client_addr
, pagesize
);
699 range
.len
= pagesize
;
700 ret
= ioctl(pcfd
->fd
, UFFDIO_WAKE
, &range
);
702 error_report("%s: Failed to wake: %zx in %s (%s)",
703 __func__
, (size_t)client_addr
, qemu_ram_get_idstr(rb
),
709 static int postcopy_request_page(MigrationIncomingState
*mis
, RAMBlock
*rb
,
710 ram_addr_t start
, uint64_t haddr
)
712 void *aligned
= (void *)(uintptr_t)ROUND_DOWN(haddr
, qemu_ram_pagesize(rb
));
715 * Discarded pages (via RamDiscardManager) are never migrated. On unlikely
716 * access, place a zeropage, which will also set the relevant bits in the
717 * recv_bitmap accordingly, so we won't try placing a zeropage twice.
719 * Checking a single bit is sufficient to handle pagesize > TPS as either
720 * all relevant bits are set or not.
722 assert(QEMU_IS_ALIGNED(start
, qemu_ram_pagesize(rb
)));
723 if (ramblock_page_is_discarded(rb
, start
)) {
724 bool received
= ramblock_recv_bitmap_test_byte_offset(rb
, start
);
726 return received
? 0 : postcopy_place_page_zero(mis
, aligned
, rb
);
729 return migrate_send_rp_req_pages(mis
, rb
, start
, haddr
);
733 * Callback from shared fault handlers to ask for a page,
734 * the page must be specified by a RAMBlock and an offset in that rb
735 * Note: Only for use by shared fault handlers (in fault thread)
737 int postcopy_request_shared_page(struct PostCopyFD
*pcfd
, RAMBlock
*rb
,
738 uint64_t client_addr
, uint64_t rb_offset
)
740 uint64_t aligned_rbo
= ROUND_DOWN(rb_offset
, qemu_ram_pagesize(rb
));
741 MigrationIncomingState
*mis
= migration_incoming_get_current();
743 trace_postcopy_request_shared_page(pcfd
->idstr
, qemu_ram_get_idstr(rb
),
745 if (ramblock_recv_bitmap_test_byte_offset(rb
, aligned_rbo
)) {
746 trace_postcopy_request_shared_page_present(pcfd
->idstr
,
747 qemu_ram_get_idstr(rb
), rb_offset
);
748 return postcopy_wake_shared(pcfd
, client_addr
, rb
);
750 postcopy_request_page(mis
, rb
, aligned_rbo
, client_addr
);
754 static int get_mem_fault_cpu_index(uint32_t pid
)
758 CPU_FOREACH(cpu_iter
) {
759 if (cpu_iter
->thread_id
== pid
) {
760 trace_get_mem_fault_cpu_index(cpu_iter
->cpu_index
, pid
);
761 return cpu_iter
->cpu_index
;
764 trace_get_mem_fault_cpu_index(-1, pid
);
768 static uint32_t get_low_time_offset(PostcopyBlocktimeContext
*dc
)
770 int64_t start_time_offset
= qemu_clock_get_ms(QEMU_CLOCK_REALTIME
) -
772 return start_time_offset
< 1 ? 1 : start_time_offset
& UINT32_MAX
;
776 * This function is being called when pagefault occurs. It
777 * tracks down vCPU blocking time.
779 * @addr: faulted host virtual address
780 * @ptid: faulted process thread id
781 * @rb: ramblock appropriate to addr
783 static void mark_postcopy_blocktime_begin(uintptr_t addr
, uint32_t ptid
,
786 int cpu
, already_received
;
787 MigrationIncomingState
*mis
= migration_incoming_get_current();
788 PostcopyBlocktimeContext
*dc
= mis
->blocktime_ctx
;
789 uint32_t low_time_offset
;
791 if (!dc
|| ptid
== 0) {
794 cpu
= get_mem_fault_cpu_index(ptid
);
799 low_time_offset
= get_low_time_offset(dc
);
800 if (dc
->vcpu_addr
[cpu
] == 0) {
801 qatomic_inc(&dc
->smp_cpus_down
);
804 qatomic_xchg(&dc
->last_begin
, low_time_offset
);
805 qatomic_xchg(&dc
->page_fault_vcpu_time
[cpu
], low_time_offset
);
806 qatomic_xchg(&dc
->vcpu_addr
[cpu
], addr
);
809 * check it here, not at the beginning of the function,
810 * due to, check could occur early than bitmap_set in
811 * qemu_ufd_copy_ioctl
813 already_received
= ramblock_recv_bitmap_test(rb
, (void *)addr
);
814 if (already_received
) {
815 qatomic_xchg(&dc
->vcpu_addr
[cpu
], 0);
816 qatomic_xchg(&dc
->page_fault_vcpu_time
[cpu
], 0);
817 qatomic_dec(&dc
->smp_cpus_down
);
819 trace_mark_postcopy_blocktime_begin(addr
, dc
, dc
->page_fault_vcpu_time
[cpu
],
820 cpu
, already_received
);
824 * This function just provide calculated blocktime per cpu and trace it.
825 * Total blocktime is calculated in mark_postcopy_blocktime_end.
828 * Assume we have 3 CPU
831 * -----***********------------xxx***************------------------------> CPU1
834 * ------------****************xxx---------------------------------------> CPU2
837 * ------------------------****xxx********-------------------------------> CPU3
839 * We have sequence S1,S2,E1,S3,S1,E2,E3,E1
840 * S2,E1 - doesn't match condition due to sequence S1,S2,E1 doesn't include CPU3
841 * S3,S1,E2 - sequence includes all CPUs, in this case overlap will be S1,E2 -
842 * it's a part of total blocktime.
843 * S1 - here is last_begin
844 * Legend of the picture is following:
845 * * - means blocktime per vCPU
846 * x - means overlapped blocktime (total blocktime)
848 * @addr: host virtual address
850 static void mark_postcopy_blocktime_end(uintptr_t addr
)
852 MigrationIncomingState
*mis
= migration_incoming_get_current();
853 PostcopyBlocktimeContext
*dc
= mis
->blocktime_ctx
;
854 MachineState
*ms
= MACHINE(qdev_get_machine());
855 unsigned int smp_cpus
= ms
->smp
.cpus
;
856 int i
, affected_cpu
= 0;
857 bool vcpu_total_blocktime
= false;
858 uint32_t read_vcpu_time
, low_time_offset
;
864 low_time_offset
= get_low_time_offset(dc
);
865 /* lookup cpu, to clear it,
866 * that algorithm looks straightforward, but it's not
867 * optimal, more optimal algorithm is keeping tree or hash
868 * where key is address value is a list of */
869 for (i
= 0; i
< smp_cpus
; i
++) {
870 uint32_t vcpu_blocktime
= 0;
872 read_vcpu_time
= qatomic_fetch_add(&dc
->page_fault_vcpu_time
[i
], 0);
873 if (qatomic_fetch_add(&dc
->vcpu_addr
[i
], 0) != addr
||
874 read_vcpu_time
== 0) {
877 qatomic_xchg(&dc
->vcpu_addr
[i
], 0);
878 vcpu_blocktime
= low_time_offset
- read_vcpu_time
;
880 /* we need to know is that mark_postcopy_end was due to
881 * faulted page, another possible case it's prefetched
882 * page and in that case we shouldn't be here */
883 if (!vcpu_total_blocktime
&&
884 qatomic_fetch_add(&dc
->smp_cpus_down
, 0) == smp_cpus
) {
885 vcpu_total_blocktime
= true;
887 /* continue cycle, due to one page could affect several vCPUs */
888 dc
->vcpu_blocktime
[i
] += vcpu_blocktime
;
891 qatomic_sub(&dc
->smp_cpus_down
, affected_cpu
);
892 if (vcpu_total_blocktime
) {
893 dc
->total_blocktime
+= low_time_offset
- qatomic_fetch_add(
896 trace_mark_postcopy_blocktime_end(addr
, dc
, dc
->total_blocktime
,
900 static void postcopy_pause_fault_thread(MigrationIncomingState
*mis
)
902 trace_postcopy_pause_fault_thread();
903 qemu_sem_wait(&mis
->postcopy_pause_sem_fault
);
904 trace_postcopy_pause_fault_thread_continued();
908 * Handle faults detected by the USERFAULT markings
910 static void *postcopy_ram_fault_thread(void *opaque
)
912 MigrationIncomingState
*mis
= opaque
;
918 trace_postcopy_ram_fault_thread_entry();
919 rcu_register_thread();
920 mis
->last_rb
= NULL
; /* last RAMBlock we sent part of */
921 qemu_sem_post(&mis
->thread_sync_sem
);
924 size_t pfd_len
= 2 + mis
->postcopy_remote_fds
->len
;
926 pfd
= g_new0(struct pollfd
, pfd_len
);
928 pfd
[0].fd
= mis
->userfault_fd
;
929 pfd
[0].events
= POLLIN
;
930 pfd
[1].fd
= mis
->userfault_event_fd
;
931 pfd
[1].events
= POLLIN
; /* Waiting for eventfd to go positive */
932 trace_postcopy_ram_fault_thread_fds_core(pfd
[0].fd
, pfd
[1].fd
);
933 for (index
= 0; index
< mis
->postcopy_remote_fds
->len
; index
++) {
934 struct PostCopyFD
*pcfd
= &g_array_index(mis
->postcopy_remote_fds
,
935 struct PostCopyFD
, index
);
936 pfd
[2 + index
].fd
= pcfd
->fd
;
937 pfd
[2 + index
].events
= POLLIN
;
938 trace_postcopy_ram_fault_thread_fds_extra(2 + index
, pcfd
->idstr
,
943 ram_addr_t rb_offset
;
947 * We're mainly waiting for the kernel to give us a faulting HVA,
948 * however we can be told to quit via userfault_quit_fd which is
952 poll_result
= poll(pfd
, pfd_len
, -1 /* Wait forever */);
953 if (poll_result
== -1) {
954 error_report("%s: userfault poll: %s", __func__
, strerror(errno
));
958 if (!mis
->to_src_file
) {
960 * Possibly someone tells us that the return path is
961 * broken already using the event. We should hold until
962 * the channel is rebuilt.
964 postcopy_pause_fault_thread(mis
);
967 if (pfd
[1].revents
) {
970 /* Consume the signal */
971 if (read(mis
->userfault_event_fd
, &tmp64
, 8) != 8) {
972 /* Nothing obviously nicer than posting this error. */
973 error_report("%s: read() failed", __func__
);
976 if (qatomic_read(&mis
->fault_thread_quit
)) {
977 trace_postcopy_ram_fault_thread_quit();
982 if (pfd
[0].revents
) {
984 ret
= read(mis
->userfault_fd
, &msg
, sizeof(msg
));
985 if (ret
!= sizeof(msg
)) {
986 if (errno
== EAGAIN
) {
988 * if a wake up happens on the other thread just after
989 * the poll, there is nothing to read.
994 error_report("%s: Failed to read full userfault "
996 __func__
, strerror(errno
));
999 error_report("%s: Read %d bytes from userfaultfd "
1001 __func__
, ret
, sizeof(msg
));
1002 break; /* Lost alignment, don't know what we'd read next */
1005 if (msg
.event
!= UFFD_EVENT_PAGEFAULT
) {
1006 error_report("%s: Read unexpected event %ud from userfaultfd",
1007 __func__
, msg
.event
);
1008 continue; /* It's not a page fault, shouldn't happen */
1011 rb
= qemu_ram_block_from_host(
1012 (void *)(uintptr_t)msg
.arg
.pagefault
.address
,
1015 error_report("postcopy_ram_fault_thread: Fault outside guest: %"
1016 PRIx64
, (uint64_t)msg
.arg
.pagefault
.address
);
1020 rb_offset
= ROUND_DOWN(rb_offset
, qemu_ram_pagesize(rb
));
1021 trace_postcopy_ram_fault_thread_request(msg
.arg
.pagefault
.address
,
1022 qemu_ram_get_idstr(rb
),
1024 msg
.arg
.pagefault
.feat
.ptid
);
1025 mark_postcopy_blocktime_begin(
1026 (uintptr_t)(msg
.arg
.pagefault
.address
),
1027 msg
.arg
.pagefault
.feat
.ptid
, rb
);
1031 * Send the request to the source - we want to request one
1032 * of our host page sizes (which is >= TPS)
1034 ret
= postcopy_request_page(mis
, rb
, rb_offset
,
1035 msg
.arg
.pagefault
.address
);
1037 /* May be network failure, try to wait for recovery */
1038 postcopy_pause_fault_thread(mis
);
1043 /* Now handle any requests from external processes on shared memory */
1044 /* TODO: May need to handle devices deregistering during postcopy */
1045 for (index
= 2; index
< pfd_len
&& poll_result
; index
++) {
1046 if (pfd
[index
].revents
) {
1047 struct PostCopyFD
*pcfd
=
1048 &g_array_index(mis
->postcopy_remote_fds
,
1049 struct PostCopyFD
, index
- 2);
1052 if (pfd
[index
].revents
& POLLERR
) {
1053 error_report("%s: POLLERR on poll %zd fd=%d",
1054 __func__
, index
, pcfd
->fd
);
1055 pfd
[index
].events
= 0;
1059 ret
= read(pcfd
->fd
, &msg
, sizeof(msg
));
1060 if (ret
!= sizeof(msg
)) {
1061 if (errno
== EAGAIN
) {
1063 * if a wake up happens on the other thread just after
1064 * the poll, there is nothing to read.
1069 error_report("%s: Failed to read full userfault "
1070 "message: %s (shared) revents=%d",
1071 __func__
, strerror(errno
),
1072 pfd
[index
].revents
);
1073 /*TODO: Could just disable this sharer */
1076 error_report("%s: Read %d bytes from userfaultfd "
1077 "expected %zd (shared)",
1078 __func__
, ret
, sizeof(msg
));
1079 /*TODO: Could just disable this sharer */
1080 break; /*Lost alignment,don't know what we'd read next*/
1083 if (msg
.event
!= UFFD_EVENT_PAGEFAULT
) {
1084 error_report("%s: Read unexpected event %ud "
1085 "from userfaultfd (shared)",
1086 __func__
, msg
.event
);
1087 continue; /* It's not a page fault, shouldn't happen */
1089 /* Call the device handler registered with us */
1090 ret
= pcfd
->handler(pcfd
, &msg
);
1092 error_report("%s: Failed to resolve shared fault on %zd/%s",
1093 __func__
, index
, pcfd
->idstr
);
1094 /* TODO: Fail? Disable this sharer? */
1099 rcu_unregister_thread();
1100 trace_postcopy_ram_fault_thread_exit();
1105 static int postcopy_temp_pages_setup(MigrationIncomingState
*mis
)
1107 PostcopyTmpPage
*tmp_page
;
1108 int err
, i
, channels
;
1111 if (migrate_postcopy_preempt()) {
1112 /* If preemption enabled, need extra channel for urgent requests */
1113 mis
->postcopy_channels
= RAM_CHANNEL_MAX
;
1115 /* Both precopy/postcopy on the same channel */
1116 mis
->postcopy_channels
= 1;
1119 channels
= mis
->postcopy_channels
;
1120 mis
->postcopy_tmp_pages
= g_malloc0_n(sizeof(PostcopyTmpPage
), channels
);
1122 for (i
= 0; i
< channels
; i
++) {
1123 tmp_page
= &mis
->postcopy_tmp_pages
[i
];
1124 temp_page
= mmap(NULL
, mis
->largest_page_size
, PROT_READ
| PROT_WRITE
,
1125 MAP_PRIVATE
| MAP_ANONYMOUS
, -1, 0);
1126 if (temp_page
== MAP_FAILED
) {
1128 error_report("%s: Failed to map postcopy_tmp_pages[%d]: %s",
1129 __func__
, i
, strerror(err
));
1130 /* Clean up will be done later */
1133 tmp_page
->tmp_huge_page
= temp_page
;
1134 /* Initialize default states for each tmp page */
1135 postcopy_temp_page_reset(tmp_page
);
1139 * Map large zero page when kernel can't use UFFDIO_ZEROPAGE for hugepages
1141 mis
->postcopy_tmp_zero_page
= mmap(NULL
, mis
->largest_page_size
,
1142 PROT_READ
| PROT_WRITE
,
1143 MAP_PRIVATE
| MAP_ANONYMOUS
, -1, 0);
1144 if (mis
->postcopy_tmp_zero_page
== MAP_FAILED
) {
1146 mis
->postcopy_tmp_zero_page
= NULL
;
1147 error_report("%s: Failed to map large zero page %s",
1148 __func__
, strerror(err
));
1152 memset(mis
->postcopy_tmp_zero_page
, '\0', mis
->largest_page_size
);
1157 int postcopy_ram_incoming_setup(MigrationIncomingState
*mis
)
1159 /* Open the fd for the kernel to give us userfaults */
1160 mis
->userfault_fd
= uffd_open(O_CLOEXEC
| O_NONBLOCK
);
1161 if (mis
->userfault_fd
== -1) {
1162 error_report("%s: Failed to open userfault fd: %s", __func__
,
1168 * Although the host check already tested the API, we need to
1169 * do the check again as an ABI handshake on the new fd.
1171 if (!ufd_check_and_apply(mis
->userfault_fd
, mis
)) {
1175 /* Now an eventfd we use to tell the fault-thread to quit */
1176 mis
->userfault_event_fd
= eventfd(0, EFD_CLOEXEC
);
1177 if (mis
->userfault_event_fd
== -1) {
1178 error_report("%s: Opening userfault_event_fd: %s", __func__
,
1180 close(mis
->userfault_fd
);
1184 postcopy_thread_create(mis
, &mis
->fault_thread
, "fault-default",
1185 postcopy_ram_fault_thread
, QEMU_THREAD_JOINABLE
);
1186 mis
->have_fault_thread
= true;
1188 /* Mark so that we get notified of accesses to unwritten areas */
1189 if (foreach_not_ignored_block(ram_block_enable_notify
, mis
)) {
1190 error_report("ram_block_enable_notify failed");
1194 if (postcopy_temp_pages_setup(mis
)) {
1195 /* Error dumped in the sub-function */
1199 if (migrate_postcopy_preempt()) {
1201 * The preempt channel is established in asynchronous way. Wait
1202 * for its completion.
1204 qemu_sem_wait(&mis
->postcopy_qemufile_dst_done
);
1206 * This thread needs to be created after the temp pages because
1207 * it'll fetch RAM_CHANNEL_POSTCOPY PostcopyTmpPage immediately.
1209 postcopy_thread_create(mis
, &mis
->postcopy_prio_thread
, "fault-fast",
1210 postcopy_preempt_thread
, QEMU_THREAD_JOINABLE
);
1211 mis
->postcopy_prio_thread_created
= true;
1214 trace_postcopy_ram_enable_notify();
1219 static int qemu_ufd_copy_ioctl(MigrationIncomingState
*mis
, void *host_addr
,
1220 void *from_addr
, uint64_t pagesize
, RAMBlock
*rb
)
1222 int userfault_fd
= mis
->userfault_fd
;
1226 struct uffdio_copy copy_struct
;
1227 copy_struct
.dst
= (uint64_t)(uintptr_t)host_addr
;
1228 copy_struct
.src
= (uint64_t)(uintptr_t)from_addr
;
1229 copy_struct
.len
= pagesize
;
1230 copy_struct
.mode
= 0;
1231 ret
= ioctl(userfault_fd
, UFFDIO_COPY
, ©_struct
);
1233 struct uffdio_zeropage zero_struct
;
1234 zero_struct
.range
.start
= (uint64_t)(uintptr_t)host_addr
;
1235 zero_struct
.range
.len
= pagesize
;
1236 zero_struct
.mode
= 0;
1237 ret
= ioctl(userfault_fd
, UFFDIO_ZEROPAGE
, &zero_struct
);
1240 qemu_mutex_lock(&mis
->page_request_mutex
);
1241 ramblock_recv_bitmap_set_range(rb
, host_addr
,
1242 pagesize
/ qemu_target_page_size());
1244 * If this page resolves a page fault for a previous recorded faulted
1245 * address, take a special note to maintain the requested page list.
1247 if (g_tree_lookup(mis
->page_requested
, host_addr
)) {
1248 g_tree_remove(mis
->page_requested
, host_addr
);
1249 mis
->page_requested_count
--;
1250 trace_postcopy_page_req_del(host_addr
, mis
->page_requested_count
);
1252 qemu_mutex_unlock(&mis
->page_request_mutex
);
1253 mark_postcopy_blocktime_end((uintptr_t)host_addr
);
1258 int postcopy_notify_shared_wake(RAMBlock
*rb
, uint64_t offset
)
1261 MigrationIncomingState
*mis
= migration_incoming_get_current();
1262 GArray
*pcrfds
= mis
->postcopy_remote_fds
;
1264 for (i
= 0; i
< pcrfds
->len
; i
++) {
1265 struct PostCopyFD
*cur
= &g_array_index(pcrfds
, struct PostCopyFD
, i
);
1266 int ret
= cur
->waker(cur
, rb
, offset
);
1275 * Place a host page (from) at (host) atomically
1276 * returns 0 on success
1278 int postcopy_place_page(MigrationIncomingState
*mis
, void *host
, void *from
,
1281 size_t pagesize
= qemu_ram_pagesize(rb
);
1283 /* copy also acks to the kernel waking the stalled thread up
1284 * TODO: We can inhibit that ack and only do it if it was requested
1285 * which would be slightly cheaper, but we'd have to be careful
1286 * of the order of updating our page state.
1288 if (qemu_ufd_copy_ioctl(mis
, host
, from
, pagesize
, rb
)) {
1290 error_report("%s: %s copy host: %p from: %p (size: %zd)",
1291 __func__
, strerror(e
), host
, from
, pagesize
);
1296 trace_postcopy_place_page(host
);
1297 return postcopy_notify_shared_wake(rb
,
1298 qemu_ram_block_host_offset(rb
, host
));
1302 * Place a zero page at (host) atomically
1303 * returns 0 on success
1305 int postcopy_place_page_zero(MigrationIncomingState
*mis
, void *host
,
1308 size_t pagesize
= qemu_ram_pagesize(rb
);
1309 trace_postcopy_place_page_zero(host
);
1311 /* Normal RAMBlocks can zero a page using UFFDIO_ZEROPAGE
1312 * but it's not available for everything (e.g. hugetlbpages)
1314 if (qemu_ram_is_uf_zeroable(rb
)) {
1315 if (qemu_ufd_copy_ioctl(mis
, host
, NULL
, pagesize
, rb
)) {
1317 error_report("%s: %s zero host: %p",
1318 __func__
, strerror(e
), host
);
1322 return postcopy_notify_shared_wake(rb
,
1323 qemu_ram_block_host_offset(rb
,
1326 return postcopy_place_page(mis
, host
, mis
->postcopy_tmp_zero_page
, rb
);
1331 /* No target OS support, stubs just fail */
1332 void fill_destination_postcopy_migration_info(MigrationInfo
*info
)
1336 bool postcopy_ram_supported_by_host(MigrationIncomingState
*mis
)
1338 error_report("%s: No OS support", __func__
);
1342 int postcopy_ram_incoming_init(MigrationIncomingState
*mis
)
1344 error_report("postcopy_ram_incoming_init: No OS support");
1348 int postcopy_ram_incoming_cleanup(MigrationIncomingState
*mis
)
1354 int postcopy_ram_prepare_discard(MigrationIncomingState
*mis
)
1360 int postcopy_request_shared_page(struct PostCopyFD
*pcfd
, RAMBlock
*rb
,
1361 uint64_t client_addr
, uint64_t rb_offset
)
1367 int postcopy_ram_incoming_setup(MigrationIncomingState
*mis
)
1373 int postcopy_place_page(MigrationIncomingState
*mis
, void *host
, void *from
,
1380 int postcopy_place_page_zero(MigrationIncomingState
*mis
, void *host
,
1387 int postcopy_wake_shared(struct PostCopyFD
*pcfd
,
1388 uint64_t client_addr
,
1396 /* ------------------------------------------------------------------------- */
1397 void postcopy_temp_page_reset(PostcopyTmpPage
*tmp_page
)
1399 tmp_page
->target_pages
= 0;
1400 tmp_page
->host_addr
= NULL
;
1402 * This is set to true when reset, and cleared as long as we received any
1403 * of the non-zero small page within this huge page.
1405 tmp_page
->all_zero
= true;
1408 void postcopy_fault_thread_notify(MigrationIncomingState
*mis
)
1413 * Wakeup the fault_thread. It's an eventfd that should currently
1414 * be at 0, we're going to increment it to 1
1416 if (write(mis
->userfault_event_fd
, &tmp64
, 8) != 8) {
1417 /* Not much we can do here, but may as well report it */
1418 error_report("%s: incrementing failed: %s", __func__
,
1424 * postcopy_discard_send_init: Called at the start of each RAMBlock before
1425 * asking to discard individual ranges.
1427 * @ms: The current migration state.
1428 * @offset: the bitmap offset of the named RAMBlock in the migration bitmap.
1429 * @name: RAMBlock that discards will operate on.
1431 static PostcopyDiscardState pds
= {0};
1432 void postcopy_discard_send_init(MigrationState
*ms
, const char *name
)
1434 pds
.ramblock_name
= name
;
1441 * postcopy_discard_send_range: Called by the bitmap code for each chunk to
1442 * discard. May send a discard message, may just leave it queued to
1445 * @ms: Current migration state.
1446 * @start,@length: a range of pages in the migration bitmap in the
1447 * RAM block passed to postcopy_discard_send_init() (length=1 is one page)
1449 void postcopy_discard_send_range(MigrationState
*ms
, unsigned long start
,
1450 unsigned long length
)
1452 size_t tp_size
= qemu_target_page_size();
1453 /* Convert to byte offsets within the RAM block */
1454 pds
.start_list
[pds
.cur_entry
] = start
* tp_size
;
1455 pds
.length_list
[pds
.cur_entry
] = length
* tp_size
;
1456 trace_postcopy_discard_send_range(pds
.ramblock_name
, start
, length
);
1460 if (pds
.cur_entry
== MAX_DISCARDS_PER_COMMAND
) {
1461 /* Full set, ship it! */
1462 qemu_savevm_send_postcopy_ram_discard(ms
->to_dst_file
,
1473 * postcopy_discard_send_finish: Called at the end of each RAMBlock by the
1474 * bitmap code. Sends any outstanding discard messages, frees the PDS
1476 * @ms: Current migration state.
1478 void postcopy_discard_send_finish(MigrationState
*ms
)
1480 /* Anything unsent? */
1481 if (pds
.cur_entry
) {
1482 qemu_savevm_send_postcopy_ram_discard(ms
->to_dst_file
,
1490 trace_postcopy_discard_send_finish(pds
.ramblock_name
, pds
.nsentwords
,
1495 * Current state of incoming postcopy; note this is not part of
1496 * MigrationIncomingState since it's state is used during cleanup
1497 * at the end as MIS is being freed.
1499 static PostcopyState incoming_postcopy_state
;
1501 PostcopyState
postcopy_state_get(void)
1503 return qatomic_mb_read(&incoming_postcopy_state
);
1506 /* Set the state and return the old state */
1507 PostcopyState
postcopy_state_set(PostcopyState new_state
)
1509 return qatomic_xchg(&incoming_postcopy_state
, new_state
);
1512 /* Register a handler for external shared memory postcopy
1513 * called on the destination.
1515 void postcopy_register_shared_ufd(struct PostCopyFD
*pcfd
)
1517 MigrationIncomingState
*mis
= migration_incoming_get_current();
1519 mis
->postcopy_remote_fds
= g_array_append_val(mis
->postcopy_remote_fds
,
1523 /* Unregister a handler for external shared memory postcopy
1525 void postcopy_unregister_shared_ufd(struct PostCopyFD
*pcfd
)
1528 MigrationIncomingState
*mis
= migration_incoming_get_current();
1529 GArray
*pcrfds
= mis
->postcopy_remote_fds
;
1532 /* migration has already finished and freed the array */
1535 for (i
= 0; i
< pcrfds
->len
; i
++) {
1536 struct PostCopyFD
*cur
= &g_array_index(pcrfds
, struct PostCopyFD
, i
);
1537 if (cur
->fd
== pcfd
->fd
) {
1538 mis
->postcopy_remote_fds
= g_array_remove_index(pcrfds
, i
);
1544 void postcopy_preempt_new_channel(MigrationIncomingState
*mis
, QEMUFile
*file
)
1547 * The new loading channel has its own threads, so it needs to be
1548 * blocked too. It's by default true, just be explicit.
1550 qemu_file_set_blocking(file
, true);
1551 mis
->postcopy_qemufile_dst
= file
;
1552 qemu_sem_post(&mis
->postcopy_qemufile_dst_done
);
1553 trace_postcopy_preempt_new_channel();
1557 * Setup the postcopy preempt channel with the IOC. If ERROR is specified,
1558 * setup the error instead. This helper will free the ERROR if specified.
1561 postcopy_preempt_send_channel_done(MigrationState
*s
,
1562 QIOChannel
*ioc
, Error
*local_err
)
1565 migrate_set_error(s
, local_err
);
1566 error_free(local_err
);
1568 migration_ioc_register_yank(ioc
);
1569 s
->postcopy_qemufile_src
= qemu_file_new_output(ioc
);
1570 trace_postcopy_preempt_new_channel();
1574 * Kick the waiter in all cases. The waiter should check upon
1575 * postcopy_qemufile_src to know whether it failed or not.
1577 qemu_sem_post(&s
->postcopy_qemufile_src_sem
);
1581 postcopy_preempt_tls_handshake(QIOTask
*task
, gpointer opaque
)
1583 g_autoptr(QIOChannel
) ioc
= QIO_CHANNEL(qio_task_get_source(task
));
1584 MigrationState
*s
= opaque
;
1585 Error
*local_err
= NULL
;
1587 qio_task_propagate_error(task
, &local_err
);
1588 postcopy_preempt_send_channel_done(s
, ioc
, local_err
);
1592 postcopy_preempt_send_channel_new(QIOTask
*task
, gpointer opaque
)
1594 g_autoptr(QIOChannel
) ioc
= QIO_CHANNEL(qio_task_get_source(task
));
1595 MigrationState
*s
= opaque
;
1596 QIOChannelTLS
*tioc
;
1597 Error
*local_err
= NULL
;
1599 if (qio_task_propagate_error(task
, &local_err
)) {
1603 if (migrate_channel_requires_tls_upgrade(ioc
)) {
1604 tioc
= migration_tls_client_create(s
, ioc
, s
->hostname
, &local_err
);
1608 trace_postcopy_preempt_tls_handshake();
1609 qio_channel_set_name(QIO_CHANNEL(tioc
), "migration-tls-preempt");
1610 qio_channel_tls_handshake(tioc
, postcopy_preempt_tls_handshake
,
1612 /* Setup the channel until TLS handshake finished */
1617 /* This handles both good and error cases */
1618 postcopy_preempt_send_channel_done(s
, ioc
, local_err
);
1622 * This function will kick off an async task to establish the preempt
1623 * channel, and wait until the connection setup completed. Returns 0 if
1624 * channel established, -1 for error.
1626 int postcopy_preempt_establish_channel(MigrationState
*s
)
1628 /* If preempt not enabled, no need to wait */
1629 if (!migrate_postcopy_preempt()) {
1633 /* Kick off async task to establish preempt channel */
1634 postcopy_preempt_setup(s
);
1637 * We need the postcopy preempt channel to be established before
1638 * starting doing anything.
1640 qemu_sem_wait(&s
->postcopy_qemufile_src_sem
);
1642 return s
->postcopy_qemufile_src
? 0 : -1;
1645 void postcopy_preempt_setup(MigrationState
*s
)
1647 /* Kick an async task to connect */
1648 socket_send_channel_create(postcopy_preempt_send_channel_new
, s
);
1651 static void postcopy_pause_ram_fast_load(MigrationIncomingState
*mis
)
1653 trace_postcopy_pause_fast_load();
1654 qemu_mutex_unlock(&mis
->postcopy_prio_thread_mutex
);
1655 qemu_sem_wait(&mis
->postcopy_pause_sem_fast_load
);
1656 qemu_mutex_lock(&mis
->postcopy_prio_thread_mutex
);
1657 trace_postcopy_pause_fast_load_continued();
1660 void *postcopy_preempt_thread(void *opaque
)
1662 MigrationIncomingState
*mis
= opaque
;
1665 trace_postcopy_preempt_thread_entry();
1667 rcu_register_thread();
1669 qemu_sem_post(&mis
->thread_sync_sem
);
1671 /* Sending RAM_SAVE_FLAG_EOS to terminate this thread */
1672 qemu_mutex_lock(&mis
->postcopy_prio_thread_mutex
);
1674 ret
= ram_load_postcopy(mis
->postcopy_qemufile_dst
,
1675 RAM_CHANNEL_POSTCOPY
);
1676 /* If error happened, go into recovery routine */
1678 postcopy_pause_ram_fast_load(mis
);
1684 qemu_mutex_unlock(&mis
->postcopy_prio_thread_mutex
);
1686 rcu_unregister_thread();
1688 trace_postcopy_preempt_thread_exit();