From e660f3651e349f658fe393917bab3ef8da44448c Mon Sep 17 00:00:00 2001 From: Laszlo Ersek 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 RH-Acked-by: Luiz Capitulino RH-Acked-by: dgibson 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 Reviewed-by: Paolo Bonzini Signed-off-by: Luiz Capitulino (cherry picked from commit 2f859f80c2077e00237ea1dfae2523ebd8377f5f) Signed-off-by: Miroslav Rezanina --- 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