diff options
| -rw-r--r-- | include/migration/migration.h | 1 | ||||
| -rw-r--r-- | migration/ram.c | 17 | ||||
| -rw-r--r-- | migration/savevm.c | 32 |
3 files changed, 39 insertions, 11 deletions
diff --git a/include/migration/migration.h b/include/migration/migration.h index 34a383ef4c..6272adfaba 100644 --- a/include/migration/migration.h +++ b/include/migration/migration.h @@ -378,6 +378,7 @@ void global_state_store_running(void); void flush_page_queue(MigrationState *ms); int ram_save_queue_pages(MigrationState *ms, const char *rbname, ram_addr_t start, ram_addr_t len); +uint64_t ram_pagesize_summary(void); PostcopyState postcopy_state_get(void); /* Set the state and return the old state */ diff --git a/migration/ram.c b/migration/ram.c index f289fcddd5..1f6397a26d 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -600,6 +600,23 @@ static void migration_bitmap_sync_init(void) iterations_prev = 0; } +/* Returns a summary bitmap of the page sizes of all RAMBlocks; + * for VMs with just normal pages this is equivalent to the + * host page size. If it's got some huge pages then it's the OR + * of all the different page sizes. + */ +uint64_t ram_pagesize_summary(void) +{ + RAMBlock *block; + uint64_t summary = 0; + + QLIST_FOREACH_RCU(block, &ram_list.blocks, next) { + summary |= block->page_size; + } + + return summary; +} + static void migration_bitmap_sync(void) { RAMBlock *block; diff --git a/migration/savevm.c b/migration/savevm.c index 26d2c44b5e..3b19a4a274 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -870,7 +870,7 @@ int qemu_savevm_send_packaged(QEMUFile *f, const uint8_t *buf, size_t len) void qemu_savevm_send_postcopy_advise(QEMUFile *f) { uint64_t tmp[2]; - tmp[0] = cpu_to_be64(getpagesize()); + tmp[0] = cpu_to_be64(ram_pagesize_summary()); tmp[1] = cpu_to_be64(1ul << qemu_target_page_bits()); trace_qemu_savevm_send_postcopy_advise(); @@ -1352,7 +1352,7 @@ static int qemu_loadvm_state_main(QEMUFile *f, MigrationIncomingState *mis); static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis) { PostcopyState ps = postcopy_state_set(POSTCOPY_INCOMING_ADVISE); - uint64_t remote_hps, remote_tps; + uint64_t remote_pagesize_summary, local_pagesize_summary, remote_tps; trace_loadvm_postcopy_handle_advise(); if (ps != POSTCOPY_INCOMING_NONE) { @@ -1365,17 +1365,27 @@ static int loadvm_postcopy_handle_advise(MigrationIncomingState *mis) return -1; } - remote_hps = qemu_get_be64(mis->from_src_file); - if (remote_hps != getpagesize()) { + remote_pagesize_summary = qemu_get_be64(mis->from_src_file); + local_pagesize_summary = ram_pagesize_summary(); + + if (remote_pagesize_summary != local_pagesize_summary) { /* - * Some combinations of mismatch are probably possible but it gets - * a bit more complicated. In particular we need to place whole - * host pages on the dest at once, and we need to ensure that we - * handle dirtying to make sure we never end up sending part of - * a hostpage on it's own. + * This detects two potential causes of mismatch: + * a) A mismatch in host page sizes + * Some combinations of mismatch are probably possible but it gets + * a bit more complicated. In particular we need to place whole + * host pages on the dest at once, and we need to ensure that we + * handle dirtying to make sure we never end up sending part of + * a hostpage on it's own. + * b) The use of different huge page sizes on source/destination + * a more fine grain test is performed during RAM block migration + * but this test here causes a nice early clear failure, and + * also fails when passed to an older qemu that doesn't + * do huge pages. */ - error_report("Postcopy needs matching host page sizes (s=%d d=%d)", - (int)remote_hps, getpagesize()); + error_report("Postcopy needs matching RAM page sizes (s=%" PRIx64 + " d=%" PRIx64 ")", + remote_pagesize_summary, local_pagesize_summary); return -1; } |