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From 3555c9b0e05c410028022a1b1af34ad7a2e83e98 Mon Sep 17 00:00:00 2001
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From: Laszlo Ersek <lersek@redhat.com>
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Date: Fri, 7 Nov 2014 17:17:59 +0100
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Subject: [PATCH 12/41] dump: add API to write dump_bitmap
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Message-id: <1415380693-16593-13-git-send-email-lersek@redhat.com>
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Patchwork-id: 62198
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O-Subject: [RHEL-7.1 qemu-kvm PATCH 12/26] dump: add API to write dump_bitmap
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Bugzilla: 1157798
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Luiz Capitulino <lcapitulino@redhat.com>
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RH-Acked-by: dgibson <dgibson@redhat.com>
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From: qiaonuohan <qiaonuohan@cn.fujitsu.com>
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functions are used to write 1st and 2nd dump_bitmap of kdump-compressed format,
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which is used to indicate whether the corresponded page is existed in vmcore.
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1st and 2nd dump_bitmap are same, because dump level is specified to 1 here.
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Signed-off-by: Qiao Nuohan <qiaonuohan@cn.fujitsu.com>
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Reviewed-by: Laszlo Ersek <lersek@redhat.com>
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Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
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(cherry picked from commit d0686c7291fe8f0210e7a666f80892fa71395510)
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Signed-off-by: Laszlo Ersek <lersek@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 dump.c                | 164 ++++++++++++++++++++++++++++++++++++++++++++++++++
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 include/sysemu/dump.h |   2 +
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 2 files changed, 166 insertions(+)
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diff --git a/dump.c b/dump.c
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index 4d135fd..f416093 100644
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--- a/dump.c
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+++ b/dump.c
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@@ -1007,6 +1007,170 @@ static int write_dump_header(DumpState *s)
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     }
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 }
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+/*
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+ * set dump_bitmap sequencely. the bit before last_pfn is not allowed to be
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+ * rewritten, so if need to set the first bit, set last_pfn and pfn to 0.
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+ * set_dump_bitmap will always leave the recently set bit un-sync. And setting
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+ * (last bit + sizeof(buf) * 8) to 0 will do flushing the content in buf into
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+ * vmcore, ie. synchronizing un-sync bit into vmcore.
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+ */
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+static int set_dump_bitmap(uint64_t last_pfn, uint64_t pfn, bool value,
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+                           uint8_t *buf, DumpState *s)
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+{
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+    off_t old_offset, new_offset;
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+    off_t offset_bitmap1, offset_bitmap2;
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+    uint32_t byte, bit;
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+
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+    /* should not set the previous place */
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+    assert(last_pfn <= pfn);
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+
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+    /*
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+     * if the bit needed to be set is not cached in buf, flush the data in buf
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+     * to vmcore firstly.
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+     * making new_offset be bigger than old_offset can also sync remained data
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+     * into vmcore.
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+     */
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+    old_offset = BUFSIZE_BITMAP * (last_pfn / PFN_BUFBITMAP);
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+    new_offset = BUFSIZE_BITMAP * (pfn / PFN_BUFBITMAP);
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+
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+    while (old_offset < new_offset) {
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+        /* calculate the offset and write dump_bitmap */
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+        offset_bitmap1 = s->offset_dump_bitmap + old_offset;
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+        if (write_buffer(s->fd, offset_bitmap1, buf,
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+                         BUFSIZE_BITMAP) < 0) {
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+            return -1;
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+        }
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+
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+        /* dump level 1 is chosen, so 1st and 2nd bitmap are same */
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+        offset_bitmap2 = s->offset_dump_bitmap + s->len_dump_bitmap +
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+                         old_offset;
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+        if (write_buffer(s->fd, offset_bitmap2, buf,
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+                         BUFSIZE_BITMAP) < 0) {
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+            return -1;
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+        }
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+
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+        memset(buf, 0, BUFSIZE_BITMAP);
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+        old_offset += BUFSIZE_BITMAP;
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+    }
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+
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+    /* get the exact place of the bit in the buf, and set it */
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+    byte = (pfn % PFN_BUFBITMAP) / CHAR_BIT;
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+    bit = (pfn % PFN_BUFBITMAP) % CHAR_BIT;
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+    if (value) {
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+        buf[byte] |= 1u << bit;
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+    } else {
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+        buf[byte] &= ~(1u << bit);
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+    }
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+
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+    return 0;
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+}
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+
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+/*
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+ * exam every page and return the page frame number and the address of the page.
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+ * bufptr can be NULL. note: the blocks here is supposed to reflect guest-phys
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+ * blocks, so block->target_start and block->target_end should be interal
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+ * multiples of the target page size.
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+ */
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+static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr,
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+                          uint8_t **bufptr, DumpState *s)
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+{
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+    GuestPhysBlock *block = *blockptr;
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+    hwaddr addr;
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+    uint8_t *buf;
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+
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+    /* block == NULL means the start of the iteration */
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+    if (!block) {
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+        block = QTAILQ_FIRST(&s->guest_phys_blocks.head);
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+        *blockptr = block;
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+        assert(block->target_start % s->page_size == 0);
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+        assert(block->target_end % s->page_size == 0);
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+        *pfnptr = paddr_to_pfn(block->target_start, s->page_shift);
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+        if (bufptr) {
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+            *bufptr = block->host_addr;
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+        }
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+        return true;
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+    }
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+
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+    *pfnptr = *pfnptr + 1;
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+    addr = pfn_to_paddr(*pfnptr, s->page_shift);
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+
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+    if ((addr >= block->target_start) &&
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+        (addr + s->page_size <= block->target_end)) {
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+        buf = block->host_addr + (addr - block->target_start);
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+    } else {
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+        /* the next page is in the next block */
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+        block = QTAILQ_NEXT(block, next);
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+        *blockptr = block;
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+        if (!block) {
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+            return false;
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+        }
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+        assert(block->target_start % s->page_size == 0);
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+        assert(block->target_end % s->page_size == 0);
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+        *pfnptr = paddr_to_pfn(block->target_start, s->page_shift);
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+        buf = block->host_addr;
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+    }
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+
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+    if (bufptr) {
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+        *bufptr = buf;
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+    }
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+
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+    return true;
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+}
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+
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+static int write_dump_bitmap(DumpState *s)
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+{
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+    int ret = 0;
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+    uint64_t last_pfn, pfn;
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+    void *dump_bitmap_buf;
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+    size_t num_dumpable;
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+    GuestPhysBlock *block_iter = NULL;
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+
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+    /* dump_bitmap_buf is used to store dump_bitmap temporarily */
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+    dump_bitmap_buf = g_malloc0(BUFSIZE_BITMAP);
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+
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+    num_dumpable = 0;
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+    last_pfn = 0;
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+
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+    /*
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+     * exam memory page by page, and set the bit in dump_bitmap corresponded
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+     * to the existing page.
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+     */
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+    while (get_next_page(&block_iter, &pfn, NULL, s)) {
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+        ret = set_dump_bitmap(last_pfn, pfn, true, dump_bitmap_buf, s);
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+        if (ret < 0) {
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+            dump_error(s, "dump: failed to set dump_bitmap.\n");
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+            ret = -1;
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+            goto out;
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+        }
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+
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+        last_pfn = pfn;
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+        num_dumpable++;
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+    }
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+
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+    /*
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+     * set_dump_bitmap will always leave the recently set bit un-sync. Here we
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+     * set last_pfn + PFN_BUFBITMAP to 0 and those set but un-sync bit will be
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+     * synchronized into vmcore.
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+     */
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+    if (num_dumpable > 0) {
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+        ret = set_dump_bitmap(last_pfn, last_pfn + PFN_BUFBITMAP, false,
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+                              dump_bitmap_buf, s);
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+        if (ret < 0) {
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+            dump_error(s, "dump: failed to sync dump_bitmap.\n");
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+            ret = -1;
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+            goto out;
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+        }
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+    }
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+
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+    /* number of dumpable pages that will be dumped later */
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+    s->num_dumpable = num_dumpable;
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+
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+out:
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+    g_free(dump_bitmap_buf);
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+
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+    return ret;
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+}
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+
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 static ram_addr_t get_start_block(DumpState *s)
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 {
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     GuestPhysBlock *block;
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diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h
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index dfee238..6d4d0bc 100644
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--- a/include/sysemu/dump.h
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+++ b/include/sysemu/dump.h
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@@ -39,6 +39,8 @@
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 #define PHYS_BASE                   (0)
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 #define DUMP_LEVEL                  (1)
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 #define DISKDUMP_HEADER_BLOCKS      (1)
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+#define BUFSIZE_BITMAP              (TARGET_PAGE_SIZE)
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+#define PFN_BUFBITMAP               (CHAR_BIT * BUFSIZE_BITMAP)
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 typedef struct ArchDumpInfo {
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     int d_machine;  /* Architecture */
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-- 
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1.8.3.1
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