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GET /api/patches/807523/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 807523,
    "url": "http://patchwork.ozlabs.org/api/patches/807523/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/1504081950-2528-21-git-send-email-peterx@redhat.com/",
    "project": {
        "id": 14,
        "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api",
        "name": "QEMU Development",
        "link_name": "qemu-devel",
        "list_id": "qemu-devel.nongnu.org",
        "list_email": "qemu-devel@nongnu.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": "",
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<1504081950-2528-21-git-send-email-peterx@redhat.com>",
    "list_archive_url": null,
    "date": "2017-08-30T08:32:17",
    "name": "[RFC,v2,20/33] migration: new message MIG_RP_MSG_RECV_BITMAP",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "899e524bdd54743eb56b07d72e204adecd777d8d",
    "submitter": {
        "id": 67717,
        "url": "http://patchwork.ozlabs.org/api/people/67717/?format=api",
        "name": "Peter Xu",
        "email": "peterx@redhat.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/1504081950-2528-21-git-send-email-peterx@redhat.com/mbox/",
    "series": [
        {
            "id": 552,
            "url": "http://patchwork.ozlabs.org/api/series/552/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=552",
            "date": "2017-08-30T08:31:59",
            "name": "Migration: postcopy failure recovery",
            "version": 2,
            "mbox": "http://patchwork.ozlabs.org/series/552/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/807523/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/807523/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>",
        "X-Original-To": "incoming@patchwork.ozlabs.org",
        "Delivered-To": "patchwork-incoming@bilbo.ozlabs.org",
        "Authentication-Results": [
            "ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=<UNKNOWN>)",
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            "ext-mx03.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=peterx@redhat.com"
        ],
        "Received": [
            "from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xhzx54BsQz9t2Q\n\tfor <incoming@patchwork.ozlabs.org>;\n\tWed, 30 Aug 2017 19:00:25 +1000 (AEST)",
            "from localhost ([::1]:49155 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>)\n\tid 1dmyrH-0005sd-8H\n\tfor incoming@patchwork.ozlabs.org; Wed, 30 Aug 2017 05:00:23 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:34652)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <peterx@redhat.com>) id 1dmySE-000869-1D\n\tfor qemu-devel@nongnu.org; Wed, 30 Aug 2017 04:34:31 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <peterx@redhat.com>) id 1dmySC-0003mF-9W\n\tfor qemu-devel@nongnu.org; Wed, 30 Aug 2017 04:34:30 -0400",
            "from mx1.redhat.com ([209.132.183.28]:49748)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <peterx@redhat.com>) id 1dmySC-0003lx-0J\n\tfor qemu-devel@nongnu.org; Wed, 30 Aug 2017 04:34:28 -0400",
            "from smtp.corp.redhat.com\n\t(int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id 01B447E42F;\n\tWed, 30 Aug 2017 08:34:27 +0000 (UTC)",
            "from pxdev.xzpeter.org.com (dhcp-14-103.nay.redhat.com\n\t[10.66.14.103])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id D30AB84792;\n\tWed, 30 Aug 2017 08:34:13 +0000 (UTC)"
        ],
        "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com 01B447E42F",
        "From": "Peter Xu <peterx@redhat.com>",
        "To": "qemu-devel@nongnu.org",
        "Date": "Wed, 30 Aug 2017 16:32:17 +0800",
        "Message-Id": "<1504081950-2528-21-git-send-email-peterx@redhat.com>",
        "In-Reply-To": "<1504081950-2528-1-git-send-email-peterx@redhat.com>",
        "References": "<1504081950-2528-1-git-send-email-peterx@redhat.com>",
        "X-Scanned-By": "MIMEDefang 2.79 on 10.5.11.15",
        "X-Greylist": "Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.27]);\n\tWed, 30 Aug 2017 08:34:27 +0000 (UTC)",
        "X-detected-operating-system": "by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]",
        "X-Received-From": "209.132.183.28",
        "Subject": "[Qemu-devel] [RFC v2 20/33] migration: new message\n\tMIG_RP_MSG_RECV_BITMAP",
        "X-BeenThere": "qemu-devel@nongnu.org",
        "X-Mailman-Version": "2.1.21",
        "Precedence": "list",
        "List-Id": "<qemu-devel.nongnu.org>",
        "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>",
        "List-Archive": "<http://lists.nongnu.org/archive/html/qemu-devel/>",
        "List-Post": "<mailto:qemu-devel@nongnu.org>",
        "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>",
        "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=subscribe>",
        "Cc": "Laurent Vivier <lvivier@redhat.com>,\n\tAndrea Arcangeli <aarcange@redhat.com>, \n\tJuan Quintela <quintela@redhat.com>,\n\tAlexey Perevalov <a.perevalov@samsung.com>, peterx@redhat.com,\n\t\"Dr . David Alan Gilbert\" <dgilbert@redhat.com>",
        "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org",
        "Sender": "\"Qemu-devel\"\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>"
    },
    "content": "Introducing new return path message MIG_RP_MSG_RECV_BITMAP to send\nreceived bitmap of ramblock back to source.\n\nThis is the reply message of MIG_CMD_RECV_BITMAP, it contains not only\nthe header (including the ramblock name), and it was appended with the\nwhole ramblock received bitmap on the destination side.\n\nWhen the source receives such a reply message (MIG_RP_MSG_RECV_BITMAP),\nit parses it, convert it to the dirty bitmap by inverting the bits.\n\nOne thing to mention is that, when we send the recv bitmap, we are doing\nthese things in extra:\n\n- converting the bitmap to little endian, to support when hosts are\n  using different endianess on src/dst.\n\n- do proper alignment for 8 bytes, to support when hosts are using\n  different word size (32/64 bits) on src/dst.\n\nSigned-off-by: Peter Xu <peterx@redhat.com>\n---\n migration/migration.c  |  68 ++++++++++++++++++++++++\n migration/migration.h  |   2 +\n migration/ram.c        | 141 +++++++++++++++++++++++++++++++++++++++++++++++++\n migration/ram.h        |   3 ++\n migration/savevm.c     |   2 +-\n migration/trace-events |   2 +\n 6 files changed, 217 insertions(+), 1 deletion(-)",
    "diff": "diff --git a/migration/migration.c b/migration/migration.c\nindex 1370c70..625f19a 100644\n--- a/migration/migration.c\n+++ b/migration/migration.c\n@@ -92,6 +92,7 @@ enum mig_rp_message_type {\n \n     MIG_RP_MSG_REQ_PAGES_ID, /* data (start: be64, len: be32, id: string) */\n     MIG_RP_MSG_REQ_PAGES,    /* data (start: be64, len: be32) */\n+    MIG_RP_MSG_RECV_BITMAP,  /* send recved_bitmap back to source */\n \n     MIG_RP_MSG_MAX\n };\n@@ -449,6 +450,45 @@ void migrate_send_rp_pong(MigrationIncomingState *mis,\n     migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);\n }\n \n+void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis,\n+                                 char *block_name)\n+{\n+    char buf[512];\n+    int len;\n+    int64_t res;\n+\n+    /*\n+     * First, we send the header part. It contains only the len of\n+     * idstr, and the idstr itself.\n+     */\n+    len = strlen(block_name);\n+    buf[0] = len;\n+    memcpy(buf + 1, block_name, len);\n+\n+    if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) {\n+        error_report(\"%s: MSG_RP_RECV_BITMAP only used for recovery\",\n+                     __func__);\n+        return;\n+    }\n+\n+    migrate_send_rp_message(mis, MIG_RP_MSG_RECV_BITMAP, len + 1, buf);\n+\n+    /*\n+     * Next, we dump the received bitmap to the stream.\n+     *\n+     * TODO: currently we are safe since we are the only one that is\n+     * using the to_src_file handle (fault thread is still paused),\n+     * and it's ok even not taking the mutex. However the best way is\n+     * to take the lock before sending the message header, and release\n+     * the lock after sending the bitmap.\n+     */\n+    qemu_mutex_lock(&mis->rp_mutex);\n+    res = ramblock_recv_bitmap_send(mis->to_src_file, block_name);\n+    qemu_mutex_unlock(&mis->rp_mutex);\n+\n+    trace_migrate_send_rp_recv_bitmap(block_name, res);\n+}\n+\n MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)\n {\n     MigrationCapabilityStatusList *head = NULL;\n@@ -1572,6 +1612,7 @@ static struct rp_cmd_args {\n     [MIG_RP_MSG_PONG]           = { .len =  4, .name = \"PONG\" },\n     [MIG_RP_MSG_REQ_PAGES]      = { .len = 12, .name = \"REQ_PAGES\" },\n     [MIG_RP_MSG_REQ_PAGES_ID]   = { .len = -1, .name = \"REQ_PAGES_ID\" },\n+    [MIG_RP_MSG_RECV_BITMAP]    = { .len = -1, .name = \"RECV_BITMAP\" },\n     [MIG_RP_MSG_MAX]            = { .len = -1, .name = \"MAX\" },\n };\n \n@@ -1616,6 +1657,19 @@ static bool postcopy_pause_return_path_thread(MigrationState *s)\n     return true;\n }\n \n+static int migrate_handle_rp_recv_bitmap(MigrationState *s, char *block_name)\n+{\n+    RAMBlock *block = qemu_ram_block_by_name(block_name);\n+\n+    if (!block) {\n+        error_report(\"%s: invalid block name '%s'\", __func__, block_name);\n+        return -EINVAL;\n+    }\n+\n+    /* Fetch the received bitmap and refresh the dirty bitmap */\n+    return ram_dirty_bitmap_reload(s, block);\n+}\n+\n /*\n  * Handles messages sent on the return path towards the source VM\n  *\n@@ -1721,6 +1775,20 @@ retry:\n             migrate_handle_rp_req_pages(ms, (char *)&buf[13], start, len);\n             break;\n \n+        case MIG_RP_MSG_RECV_BITMAP:\n+            if (header_len < 1) {\n+                error_report(\"%s: missing block name\", __func__);\n+                mark_source_rp_bad(ms);\n+                goto out;\n+            }\n+            /* Format: len (1B) + idstr (<255B). This ends the idstr. */\n+            buf[buf[0] + 1] = '\\0';\n+            if (migrate_handle_rp_recv_bitmap(ms, (char *)(buf + 1))) {\n+                mark_source_rp_bad(ms);\n+                goto out;\n+            }\n+            break;\n+\n         default:\n             break;\n         }\ndiff --git a/migration/migration.h b/migration/migration.h\nindex b78b9bd..4051379 100644\n--- a/migration/migration.h\n+++ b/migration/migration.h\n@@ -202,5 +202,7 @@ void migrate_send_rp_pong(MigrationIncomingState *mis,\n                           uint32_t value);\n int migrate_send_rp_req_pages(MigrationIncomingState *mis, const char* rbname,\n                               ram_addr_t start, size_t len);\n+void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis,\n+                                 char *block_name);\n \n #endif\ndiff --git a/migration/ram.c b/migration/ram.c\nindex 7e20097..5d938e3 100644\n--- a/migration/ram.c\n+++ b/migration/ram.c\n@@ -182,6 +182,70 @@ void ramblock_recv_bitmap_clear(RAMBlock *rb, void *host_addr)\n     clear_bit(ramblock_recv_bitmap_offset(host_addr, rb), rb->receivedmap);\n }\n \n+#define  RAMBLOCK_RECV_BITMAP_ENDING  (0x0123456789abcdefULL)\n+\n+/*\n+ * Format: bitmap_size (8 bytes) + whole_bitmap (N bytes).\n+ *\n+ * Returns >0 if success with sent bytes, or <0 if error.\n+ */\n+int64_t ramblock_recv_bitmap_send(QEMUFile *file,\n+                                  const char *block_name)\n+{\n+    RAMBlock *block = qemu_ram_block_by_name(block_name);\n+    unsigned long *le_bitmap, nbits;\n+    uint64_t size;\n+\n+    if (!block) {\n+        error_report(\"%s: invalid block name: %s\", __func__, block_name);\n+        return -1;\n+    }\n+\n+    nbits = block->used_length >> TARGET_PAGE_BITS;\n+\n+    /*\n+     * Make sure the tmp bitmap buffer is big enough, e.g., on 32bit\n+     * machines we may need 4 more bytes for padding (see below\n+     * comment). So extend it a bit before hand.\n+     */\n+    le_bitmap = bitmap_new(nbits + BITS_PER_LONG);\n+\n+    /*\n+     * Always use little endian when sending the bitmap. This is\n+     * required that when source and destination VMs are not using the\n+     * same endianess. (Note: big endian won't work.)\n+     */\n+    bitmap_to_le(le_bitmap, block->receivedmap, nbits);\n+\n+    /* Size of the bitmap, in bytes */\n+    size = nbits / 8;\n+\n+    /*\n+     * size is always aligned to 8 bytes for 64bit machines, but it\n+     * may not be true for 32bit machines. We need this padding to\n+     * make sure the migration can survive even between 32bit and\n+     * 64bit machines.\n+     */\n+    size = ROUND_UP(size, 8);\n+\n+    qemu_put_be64(file, size);\n+    qemu_put_buffer(file, (const uint8_t *)le_bitmap, size);\n+    /*\n+     * Mark as an end, in case the middle part is screwed up due to\n+     * some \"misterious\" reason.\n+     */\n+    qemu_put_be64(file, RAMBLOCK_RECV_BITMAP_ENDING);\n+    qemu_fflush(file);\n+\n+    free(le_bitmap);\n+\n+    if (qemu_file_get_error(file)) {\n+        return qemu_file_get_error(file);\n+    }\n+\n+    return size + sizeof(size);\n+}\n+\n /*\n  * An outstanding page request, on the source, having been received\n  * and queued\n@@ -2706,6 +2770,83 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)\n     return ret;\n }\n \n+/*\n+ * Read the received bitmap, revert it as the initial dirty bitmap.\n+ * This is only used when the postcopy migration is paused but wants\n+ * to resume from a middle point.\n+ */\n+int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *block)\n+{\n+    int ret = -EINVAL;\n+    QEMUFile *file = s->rp_state.from_dst_file;\n+    unsigned long *le_bitmap, nbits = block->used_length >> TARGET_PAGE_BITS;\n+    uint64_t local_size = nbits / 8;\n+    uint64_t size, end_mark;\n+\n+    if (s->state != MIGRATION_STATUS_POSTCOPY_RECOVER) {\n+        error_report(\"%s: incorrect state %s\", __func__,\n+                     MigrationStatus_lookup[s->state]);\n+        return -EINVAL;\n+    }\n+\n+    /*\n+     * Note: see comments in ramblock_recv_bitmap_send() on why we\n+     * need the endianess convertion, and the paddings.\n+     */\n+    local_size = ROUND_UP(local_size, 8);\n+\n+    /* Add addings */\n+    le_bitmap = bitmap_new(nbits + BITS_PER_LONG);\n+\n+    size = qemu_get_be64(file);\n+\n+    /* The size of the bitmap should match with our ramblock */\n+    if (size != local_size) {\n+        error_report(\"%s: ramblock '%s' bitmap size mismatch \"\n+                     \"(0x%lx != 0x%lx)\", __func__, block->idstr,\n+                     size, local_size);\n+        ret = -EINVAL;\n+        goto out;\n+    }\n+\n+    size = qemu_get_buffer(file, (uint8_t *)le_bitmap, local_size);\n+    end_mark = qemu_get_be64(file);\n+\n+    ret = qemu_file_get_error(file);\n+    if (ret || size != local_size) {\n+        error_report(\"%s: read bitmap failed for ramblock '%s': %d\",\n+                     __func__, block->idstr, ret);\n+        ret = -EIO;\n+        goto out;\n+    }\n+\n+    if (end_mark != RAMBLOCK_RECV_BITMAP_ENDING) {\n+        error_report(\"%s: ramblock '%s' end mark incorrect: 0x%\"PRIu64,\n+                     __func__, block->idstr, end_mark);\n+        ret = -EINVAL;\n+        goto out;\n+    }\n+\n+    /*\n+     * Endianess convertion. We are during postcopy (though paused).\n+     * The dirty bitmap won't change. We can directly modify it.\n+     */\n+    bitmap_from_le(block->bmap, le_bitmap, nbits);\n+\n+    /*\n+     * What we received is \"received bitmap\". Revert it as the initial\n+     * dirty bitmap for this ramblock.\n+     */\n+    bitmap_complement(block->bmap, block->bmap, nbits);\n+\n+    trace_ram_dirty_bitmap_reload(block->idstr);\n+\n+    ret = 0;\n+out:\n+    free(le_bitmap);\n+    return ret;\n+}\n+\n static SaveVMHandlers savevm_ram_handlers = {\n     .save_setup = ram_save_setup,\n     .save_live_iterate = ram_save_iterate,\ndiff --git a/migration/ram.h b/migration/ram.h\nindex 4db9922..bd4b8ba 100644\n--- a/migration/ram.h\n+++ b/migration/ram.h\n@@ -57,5 +57,8 @@ int ramblock_recv_bitmap_test(RAMBlock *rb, void *host_addr);\n void ramblock_recv_bitmap_set(RAMBlock *rb, void *host_addr);\n void ramblock_recv_bitmap_set_range(RAMBlock *rb, void *host_addr, size_t nr);\n void ramblock_recv_bitmap_clear(RAMBlock *rb, void *host_addr);\n+int64_t ramblock_recv_bitmap_send(QEMUFile *file,\n+                                  const char *block_name);\n+int ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *rb);\n \n #endif\ndiff --git a/migration/savevm.c b/migration/savevm.c\nindex f532ca0..7f77a31 100644\n--- a/migration/savevm.c\n+++ b/migration/savevm.c\n@@ -1766,7 +1766,7 @@ static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis,\n         return -EINVAL;\n     }\n \n-    /* TODO: send the bitmap back to source */\n+    migrate_send_rp_recv_bitmap(mis, block_name);\n \n     trace_loadvm_handle_recv_bitmap(block_name);\n \ndiff --git a/migration/trace-events b/migration/trace-events\nindex c5f7e41..9960cd8 100644\n--- a/migration/trace-events\n+++ b/migration/trace-events\n@@ -78,6 +78,7 @@ ram_load_postcopy_loop(uint64_t addr, int flags) \"@%\" PRIx64 \" %x\"\n ram_postcopy_send_discard_bitmap(void) \"\"\n ram_save_page(const char *rbname, uint64_t offset, void *host) \"%s: offset: 0x%\" PRIx64 \" host: %p\"\n ram_save_queue_pages(const char *rbname, size_t start, size_t len) \"%s: start: 0x%zx len: 0x%zx\"\n+ram_dirty_bitmap_reload(char *str) \"%s\"\n \n # migration/migration.c\n await_return_path_close_on_source_close(void) \"\"\n@@ -89,6 +90,7 @@ migrate_fd_cancel(void) \"\"\n migrate_handle_rp_req_pages(const char *rbname, size_t start, size_t len) \"in %s at 0x%zx len 0x%zx\"\n migrate_pending(uint64_t size, uint64_t max, uint64_t post, uint64_t nonpost) \"pending size %\" PRIu64 \" max %\" PRIu64 \" (post=%\" PRIu64 \" nonpost=%\" PRIu64 \")\"\n migrate_send_rp_message(int msg_type, uint16_t len) \"%d: len %d\"\n+migrate_send_rp_recv_bitmap(char *name, int64_t size) \"block '%s' size 0x%\"PRIi64\n migration_completion_file_err(void) \"\"\n migration_completion_postcopy_end(void) \"\"\n migration_completion_postcopy_end_after_complete(void) \"\"\n",
    "prefixes": [
        "RFC",
        "v2",
        "20/33"
    ]
}