From e660f3651e349f658fe393917bab3ef8da44448c Mon Sep 17 00:00:00 2001

From: Laszlo Ersek <lersek@redhat.com>

Date: Fri, 7 Nov 2014 17:18:10 +0100

Subject: [PATCH 23/41] dump: eliminate DumpState.page_size ("guest's page

 size")

Message-id: <1415380693-16593-24-git-send-email-lersek@redhat.com>

Patchwork-id: 62211

O-Subject: [RHEL-7.1 qemu-kvm PATCH 23/26] dump: eliminate DumpState.page_size ("guest's page size")

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>

Use TARGET_PAGE_SIZE and ~TARGET_PAGE_MASK instead.

"DumpState.page_size" has type "size_t", whereas TARGET_PAGE_SIZE has type

"int". TARGET_PAGE_MASK is of type "int" and has negative value. The patch

affects the implicit type conversions as follows:

- create_header32() and create_header64(): assigned to "block_size", which

  has type "uint32_t". No change.

- get_next_page(): "block->target_start", "block->target_end" and "addr"

  have type "hwaddr" (uint64_t).

  Before the patch,

  - if "size_t" was "uint64_t", then no additional conversion was done as

    part of the usual arithmetic conversions,

  - If "size_t" was "uint32_t", then it was widened to uint64_t as part of

    the usual arithmetic conversions,

  for the remainder and addition operators.

  After the patch,

  - "~TARGET_PAGE_MASK" expands to  ~~((1 << TARGET_PAGE_BITS) - 1). It

    has type "int" and positive value (only least significant bits set).

    That's converted (widened) to "uint64_t" for the bit-ands. No visible

    change.

  - The same holds for the (addr + TARGET_PAGE_SIZE) addition.

- write_dump_pages():

  - TARGET_PAGE_SIZE passed as argument to a bunch of functions that all

    have prototypes. No change.

  - When incrementing "offset_data" (of type "off_t"): given that we never

    build for ILP32_OFF32 (see "-D_FILE_OFFSET_BITS=64" in configure),

    "off_t" is always "int64_t", and we only need to consider:

    - ILP32_OFFBIG: "size_t" is "uint32_t".

      - before: int64_t += uint32_t. Page size converted to int64_t for

        the addition.

      - after:  int64_t += int32_t. No change.

    - LP64_OFF64: "size_t" is "uint64_t".

      - before: int64_t += uint64_t. Offset converted to uint64_t for the

        addition, then the uint64_t result is converted to int64_t for

        storage.

      - after:  int64_t += int32_t. Same as the ILP32_OFFBIG/after case.

        No visible change.

  - (size_out < s->page_size) comparisons, and (size_out = s->page_size)

    assignment:

    - before: "size_out" is of type "size_t", no implicit conversion for

              either operator.

    - after: TARGET_PAGE_SIZE (of type "int" and positive value) is

             converted to "size_t" (for the relop because the latter is

             one of "uint32_t" and "uint64_t"). No visible change.

- dump_init():

  - DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT), s->page_size): The

    innermost "DumpState.max_mapnr" field has type uint64_t, which

    propagates through all implicit conversions at hand:

    #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))

    regardless of the page size macro argument's type. In the outer macro

    replacement, the page size is converted from uint32_t and int32_t

    alike to uint64_t.

  - (tmp * s->page_size) multiplication: "tmp" has size "uint64_t"; the

    RHS is converted to that type from uint32_t and int32_t just the same

    if it's not uint64_t to begin with.

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

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

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

(cherry picked from commit 2f859f80c2077e00237ea1dfae2523ebd8377f5f)

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

---

 dump.c | 51 +++++++++++++++++++++++++--------------------------

 1 file changed, 25 insertions(+), 26 deletions(-)

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

index bc82b55..f8e0fd7 100644

--- a/dump.c

+++ b/dump.c

@@ -90,7 +90,6 @@ typedef struct DumpState {

     uint8_t *note_buf;          /* buffer for notes */

     size_t note_buf_offset;     /* the writing place in note_buf */

     uint32_t nr_cpus;           /* number of guest's cpu */

-    size_t page_size;           /* guest's page size */

     uint64_t max_mapnr;         /* the biggest guest's phys-mem's number */

     size_t len_dump_bitmap;     /* the size of the place used to store

                                    dump_bitmap in vmcore */

@@ -811,7 +810,7 @@ static int create_header32(DumpState *s)

     strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));

     dh->header_version = cpu_convert_to_target32(6, endian);

-    block_size = s->page_size;

+    block_size = TARGET_PAGE_SIZE;

     dh->block_size = cpu_convert_to_target32(block_size, endian);

     sub_hdr_size = sizeof(struct KdumpSubHeader32) + s->note_size;

     sub_hdr_size = DIV_ROUND_UP(sub_hdr_size, block_size);

@@ -918,7 +917,7 @@ static int create_header64(DumpState *s)

     strncpy(dh->signature, KDUMP_SIGNATURE, strlen(KDUMP_SIGNATURE));

     dh->header_version = cpu_convert_to_target32(6, endian);

-    block_size = s->page_size;

+    block_size = TARGET_PAGE_SIZE;

     dh->block_size = cpu_convert_to_target32(block_size, endian);

     sub_hdr_size = sizeof(struct KdumpSubHeader64) + s->note_size;

     sub_hdr_size = DIV_ROUND_UP(sub_hdr_size, block_size);

@@ -1089,8 +1088,8 @@ static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr,

     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);

+        assert((block->target_start & ~TARGET_PAGE_MASK) == 0);

+        assert((block->target_end & ~TARGET_PAGE_MASK) == 0);

         *pfnptr = paddr_to_pfn(block->target_start);

         if (bufptr) {

             *bufptr = block->host_addr;

@@ -1102,7 +1101,7 @@ static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr,

     addr = pfn_to_paddr(*pfnptr);

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

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

+        (addr + TARGET_PAGE_SIZE <= block->target_end)) {

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

     } else {

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

@@ -1111,8 +1110,8 @@ static bool get_next_page(GuestPhysBlock **blockptr, uint64_t *pfnptr,

         if (!block) {

             return false;

         }

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

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

+        assert((block->target_start & ~TARGET_PAGE_MASK) == 0);

+        assert((block->target_end & ~TARGET_PAGE_MASK) == 0);

         *pfnptr = paddr_to_pfn(block->target_start);

         buf = block->host_addr;

     }

@@ -1297,7 +1296,7 @@ static int write_dump_pages(DumpState *s)

     prepare_data_cache(&page_data, s, offset_data);

     /* prepare buffer to store compressed data */

-    len_buf_out = get_len_buf_out(s->page_size, s->flag_compress);

+    len_buf_out = get_len_buf_out(TARGET_PAGE_SIZE, s->flag_compress);

     if (len_buf_out == 0) {

         dump_error(s, "dump: failed to get length of output buffer.\n");

         goto out;

@@ -1313,19 +1312,19 @@ static int write_dump_pages(DumpState *s)

      * init zero page's page_desc and page_data, because every zero page

      * uses the same page_data

      */

-    pd_zero.size = cpu_convert_to_target32(s->page_size, endian);

+    pd_zero.size = cpu_convert_to_target32(TARGET_PAGE_SIZE, endian);

     pd_zero.flags = cpu_convert_to_target32(0, endian);

     pd_zero.offset = cpu_convert_to_target64(offset_data, endian);

     pd_zero.page_flags = cpu_convert_to_target64(0, endian);

-    buf = g_malloc0(s->page_size);

-    ret = write_cache(&page_data, buf, s->page_size, false);

+    buf = g_malloc0(TARGET_PAGE_SIZE);

+    ret = write_cache(&page_data, buf, TARGET_PAGE_SIZE, false);

     g_free(buf);

     if (ret < 0) {

         dump_error(s, "dump: failed to write page data(zero page).\n");

         goto out;

     }

-    offset_data += s->page_size;

+    offset_data += TARGET_PAGE_SIZE;

     /*

      * dump memory to vmcore page by page. zero page will all be resided in the

@@ -1333,7 +1332,7 @@ static int write_dump_pages(DumpState *s)

      */

     while (get_next_page(&block_iter, &pfn_iter, &buf, s)) {

         /* check zero page */

-        if (is_zero_page(buf, s->page_size)) {

+        if (is_zero_page(buf, TARGET_PAGE_SIZE)) {

             ret = write_cache(&page_desc, &pd_zero, sizeof(PageDescriptor),

                               false);

             if (ret < 0) {

@@ -1354,8 +1353,9 @@ static int write_dump_pages(DumpState *s)

              */

              size_out = len_buf_out;

              if ((s->flag_compress & DUMP_DH_COMPRESSED_ZLIB) &&

-                    (compress2(buf_out, (uLongf *)&size_out, buf, s->page_size,

-                    Z_BEST_SPEED) == Z_OK) && (size_out < s->page_size)) {

+                 (compress2(buf_out, (uLongf *)&size_out, buf,

+                            TARGET_PAGE_SIZE, Z_BEST_SPEED) == Z_OK) &&

+                 (size_out < TARGET_PAGE_SIZE)) {

                 pd.flags = cpu_convert_to_target32(DUMP_DH_COMPRESSED_ZLIB,

                                                    endian);

                 pd.size  = cpu_convert_to_target32(size_out, endian);

@@ -1367,9 +1367,9 @@ static int write_dump_pages(DumpState *s)

                 }

 #ifdef CONFIG_LZO

             } else if ((s->flag_compress & DUMP_DH_COMPRESSED_LZO) &&

-                    (lzo1x_1_compress(buf, s->page_size, buf_out,

+                    (lzo1x_1_compress(buf, TARGET_PAGE_SIZE, buf_out,

                     (lzo_uint *)&size_out, wrkmem) == LZO_E_OK) &&

-                    (size_out < s->page_size)) {

+                    (size_out < TARGET_PAGE_SIZE)) {

                 pd.flags = cpu_convert_to_target32(DUMP_DH_COMPRESSED_LZO,

                                                    endian);

                 pd.size  = cpu_convert_to_target32(size_out, endian);

@@ -1382,9 +1382,9 @@ static int write_dump_pages(DumpState *s)

 #endif

 #ifdef CONFIG_SNAPPY

             } else if ((s->flag_compress & DUMP_DH_COMPRESSED_SNAPPY) &&

-                    (snappy_compress((char *)buf, s->page_size,

+                    (snappy_compress((char *)buf, TARGET_PAGE_SIZE,

                     (char *)buf_out, &size_out) == SNAPPY_OK) &&

-                    (size_out < s->page_size)) {

+                    (size_out < TARGET_PAGE_SIZE)) {

                 pd.flags = cpu_convert_to_target32(

                                         DUMP_DH_COMPRESSED_SNAPPY, endian);

                 pd.size  = cpu_convert_to_target32(size_out, endian);

@@ -1398,13 +1398,13 @@ static int write_dump_pages(DumpState *s)

             } else {

                 /*

                  * fall back to save in plaintext, size_out should be

-                 * assigned to s->page_size

+                 * assigned TARGET_PAGE_SIZE

                  */

                 pd.flags = cpu_convert_to_target32(0, endian);

-                size_out = s->page_size;

+                size_out = TARGET_PAGE_SIZE;

                 pd.size = cpu_convert_to_target32(size_out, endian);

-                ret = write_cache(&page_data, buf, s->page_size, false);

+                ret = write_cache(&page_data, buf, TARGET_PAGE_SIZE, false);

                 if (ret < 0) {

                     dump_error(s, "dump: failed to write page data.\n");

                     goto out;

@@ -1616,13 +1616,12 @@ static int dump_init(DumpState *s, int fd, bool has_format,

     }

     s->nr_cpus = nr_cpus;

-    s->page_size = TARGET_PAGE_SIZE;

     get_max_mapnr(s);

     uint64_t tmp;

-    tmp = DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT), s->page_size);

-    s->len_dump_bitmap = tmp * s->page_size;

+    tmp = DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT), TARGET_PAGE_SIZE);

+    s->len_dump_bitmap = tmp * TARGET_PAGE_SIZE;

     /* init for kdump-compressed format */

     if (has_format && format != DUMP_GUEST_MEMORY_FORMAT_ELF) {

-- 

1.8.3.1