From 3555c9b0e05c410028022a1b1af34ad7a2e83e98 Mon Sep 17 00:00:00 2001

From: Laszlo Ersek <lersek@redhat.com>

Date: Fri, 7 Nov 2014 17:17:59 +0100

Subject: [PATCH 12/41] dump: add API to write dump_bitmap

Message-id: <1415380693-16593-13-git-send-email-lersek@redhat.com>

Patchwork-id: 62198

O-Subject: [RHEL-7.1 qemu-kvm PATCH 12/26] dump: add API to write dump_bitmap

Bugzilla: 1157798

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Luiz Capitulino <lcapitulino@redhat.com>

RH-Acked-by: dgibson <dgibson@redhat.com>

From: qiaonuohan <qiaonuohan@cn.fujitsu.com>

functions are used to write 1st and 2nd dump_bitmap of kdump-compressed format,

which is used to indicate whether the corresponded page is existed in vmcore.

1st and 2nd dump_bitmap are same, because dump level is specified to 1 here.

Signed-off-by: Qiao Nuohan <qiaonuohan@cn.fujitsu.com>

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

(cherry picked from commit d0686c7291fe8f0210e7a666f80892fa71395510)

Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 dump.c                | 164 ++++++++++++++++++++++++++++++++++++++++++++++++++

 include/sysemu/dump.h |   2 +

 2 files changed, 166 insertions(+)

diff --git a/dump.c b/dump.c

index 4d135fd..f416093 100644

--- a/dump.c

+++ b/dump.c

@@ -1007,6 +1007,170 @@ static int write_dump_header(DumpState *s)

     }

 }

+/*

+ * set dump_bitmap sequencely. the bit before last_pfn is not allowed to be

+ * rewritten, so if need to set the first bit, set last_pfn and pfn to 0.

+ * set_dump_bitmap will always leave the recently set bit un-sync. And setting

+ * (last bit + sizeof(buf) * 8) to 0 will do flushing the content in buf into

+ * vmcore, ie. synchronizing un-sync bit into vmcore.

+ */

+static int set_dump_bitmap(uint64_t last_pfn, uint64_t pfn, bool value,

+                           uint8_t *buf, DumpState *s)

+{

+    off_t old_offset, new_offset;

+    off_t offset_bitmap1, offset_bitmap2;

+    uint32_t byte, bit;

+

+    /* should not set the previous place */

+    assert(last_pfn <= pfn);

+

+    /*

+     * if the bit needed to be set is not cached in buf, flush the data in buf

+     * to vmcore firstly.

+     * making new_offset be bigger than old_offset can also sync remained data

+     * into vmcore.

+     */

+    old_offset = BUFSIZE_BITMAP * (last_pfn / PFN_BUFBITMAP);

+    new_offset = BUFSIZE_BITMAP * (pfn / PFN_BUFBITMAP);

+

+    while (old_offset < new_offset) {

+        /* calculate the offset and write dump_bitmap */

+        offset_bitmap1 = s->offset_dump_bitmap + old_offset;

+        if (write_buffer(s->fd, offset_bitmap1, buf,

+                         BUFSIZE_BITMAP) < 0) {

+            return -1;

+        }

+

+        /* dump level 1 is chosen, so 1st and 2nd bitmap are same */

+        offset_bitmap2 = s->offset_dump_bitmap + s->len_dump_bitmap +

+                         old_offset;

+        if (write_buffer(s->fd, offset_bitmap2, buf,

+                         BUFSIZE_BITMAP) < 0) {

+            return -1;

+        }

+

+        memset(buf, 0, BUFSIZE_BITMAP);

+        old_offset += BUFSIZE_BITMAP;

+    }

+

+    /* get the exact place of the bit in the buf, and set it */

+    byte = (pfn % PFN_BUFBITMAP) / CHAR_BIT;

+    bit = (pfn % PFN_BUFBITMAP) % CHAR_BIT;

+    if (value) {

+        buf[byte] |= 1u << bit;

+    } else {

+        buf[byte] &= ~(1u << bit);

+    }

+

+    return 0;

+}

+

+/*

+ * exam every page and return the page frame number and the address of the page.

+ * bufptr can be NULL. note: the blocks here is supposed to reflect guest-phys

+ * blocks, so block->target_start and block->target_end should be interal

+ * multiples of the target page size.

+ */

+static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr,

+                          uint8_t **bufptr, DumpState *s)

+{

+    GuestPhysBlock *block = *blockptr;

+    hwaddr addr;

+    uint8_t *buf;

+

+    /* block == NULL means the start of the iteration */

+    if (!block) {

+        block = QTAILQ_FIRST(&s->guest_phys_blocks.head);

+        *blockptr = block;

+        assert(block->target_start % s->page_size == 0);

+        assert(block->target_end % s->page_size == 0);

+        *pfnptr = paddr_to_pfn(block->target_start, s->page_shift);

+        if (bufptr) {

+            *bufptr = block->host_addr;

+        }

+        return true;

+    }

+

+    *pfnptr = *pfnptr + 1;

+    addr = pfn_to_paddr(*pfnptr, s->page_shift);

+

+    if ((addr >= block->target_start) &&

+        (addr + s->page_size <= block->target_end)) {

+        buf = block->host_addr + (addr - block->target_start);

+    } else {

+        /* the next page is in the next block */

+        block = QTAILQ_NEXT(block, next);

+        *blockptr = block;

+        if (!block) {

+            return false;

+        }

+        assert(block->target_start % s->page_size == 0);

+        assert(block->target_end % s->page_size == 0);

+        *pfnptr = paddr_to_pfn(block->target_start, s->page_shift);

+        buf = block->host_addr;

+    }

+

+    if (bufptr) {

+        *bufptr = buf;

+    }

+

+    return true;

+}

+

+static int write_dump_bitmap(DumpState *s)

+{

+    int ret = 0;

+    uint64_t last_pfn, pfn;

+    void *dump_bitmap_buf;

+    size_t num_dumpable;

+    GuestPhysBlock *block_iter = NULL;

+

+    /* dump_bitmap_buf is used to store dump_bitmap temporarily */

+    dump_bitmap_buf = g_malloc0(BUFSIZE_BITMAP);

+

+    num_dumpable = 0;

+    last_pfn = 0;

+

+    /*

+     * exam memory page by page, and set the bit in dump_bitmap corresponded

+     * to the existing page.

+     */

+    while (get_next_page(&block_iter, &pfn, NULL, s)) {

+        ret = set_dump_bitmap(last_pfn, pfn, true, dump_bitmap_buf, s);

+        if (ret < 0) {

+            dump_error(s, "dump: failed to set dump_bitmap.\n");

+            ret = -1;

+            goto out;

+        }

+

+        last_pfn = pfn;

+        num_dumpable++;

+    }

+

+    /*

+     * set_dump_bitmap will always leave the recently set bit un-sync. Here we

+     * set last_pfn + PFN_BUFBITMAP to 0 and those set but un-sync bit will be

+     * synchronized into vmcore.

+     */

+    if (num_dumpable > 0) {

+        ret = set_dump_bitmap(last_pfn, last_pfn + PFN_BUFBITMAP, false,

+                              dump_bitmap_buf, s);

+        if (ret < 0) {

+            dump_error(s, "dump: failed to sync dump_bitmap.\n");

+            ret = -1;

+            goto out;

+        }

+    }

+

+    /* number of dumpable pages that will be dumped later */

+    s->num_dumpable = num_dumpable;

+

+out:

+    g_free(dump_bitmap_buf);

+

+    return ret;

+}

+

 static ram_addr_t get_start_block(DumpState *s)

 {

     GuestPhysBlock *block;

diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h

index dfee238..6d4d0bc 100644

--- a/include/sysemu/dump.h

+++ b/include/sysemu/dump.h

@@ -39,6 +39,8 @@

 #define PHYS_BASE                   (0)

 #define DUMP_LEVEL                  (1)

 #define DISKDUMP_HEADER_BLOCKS      (1)

+#define BUFSIZE_BITMAP              (TARGET_PAGE_SIZE)

+#define PFN_BUFBITMAP               (CHAR_BIT * BUFSIZE_BITMAP)

 typedef struct ArchDumpInfo {

     int d_machine;  /* Architecture */

-- 

1.8.3.1