[Qemu-devel] [PATCH 0/3] multiboot: Fix offset of bootloader name

[Qemu-devel] [PATCH 0/3] multiboot: Fix offset of bootloader name

[Kevin Wolf]

This fixes a recent Multiboot load regression (see patch 2) that we
noticed while hacking on the advent calendar image for December 24.

Kevin Wolf (3):
  tests/multiboot: Update reference output
  multiboot: Fix offset of bootloader name
  tests/multiboot: Add test for modules

 hw/i386/multiboot.c         | 16 +++++++------
 tests/multiboot/Makefile    |  5 ++++-
 tests/multiboot/libc.c      | 12 ++++++++++
 tests/multiboot/libc.h      |  1 +
 tests/multiboot/mmap.out    | 37 +++++++++++++++---------------
 tests/multiboot/module.txt  |  1 +
 tests/multiboot/modules.c   | 55 +++++++++++++++++++++++++++++++++++++++++++++
 tests/multiboot/modules.out | 38 +++++++++++++++++++++++++++++++
 tests/multiboot/run_test.sh |  9 +++++++-
 9 files changed, 146 insertions(+), 28 deletions(-)
 create mode 100644 tests/multiboot/module.txt
 create mode 100644 tests/multiboot/modules.c
 create mode 100644 tests/multiboot/modules.out

-- 
1.8.3.1

[Qemu-devel] [PATCH 1/3] tests/multiboot: Update reference output

[Kevin Wolf]

The changes look okay (larger PCI hole, some rounding differences), so
just update the reference output of the test case.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/multiboot/mmap.out | 37 ++++++++++++++++++-------------------
 1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/tests/multiboot/mmap.out b/tests/multiboot/mmap.out
index e70b6eb..003e109 100644
--- a/tests/multiboot/mmap.out
+++ b/tests/multiboot/mmap.out
@@ -4,14 +4,14 @@
 === Running test case: mmap.elf  ===
 
 Lower memory: 639k
-Upper memory: 130040k
+Upper memory: 129920k
 
 e820 memory map:
 0x0 - 0x9fc00: type 1 [entry size: 20]
 0x9fc00 - 0xa0000: type 2 [entry size: 20]
 0xf0000 - 0x100000: type 2 [entry size: 20]
-0x100000 - 0x7ffe000: type 1 [entry size: 20]
-0x7ffe000 - 0x8000000: type 2 [entry size: 20]
+0x100000 - 0x7fe0000: type 1 [entry size: 20]
+0x7fe0000 - 0x8000000: type 2 [entry size: 20]
 0xfffc0000 - 0x100000000: type 2 [entry size: 20]
 
 mmap start:       0x9000
@@ -22,32 +22,31 @@ real mmap end:    0x9090
 === Running test case: mmap.elf -m 1.1M ===
 
 Lower memory: 639k
-Upper memory: 96k
+Upper memory: 104k
 
 e820 memory map:
 0x0 - 0x9fc00: type 1 [entry size: 20]
 0x9fc00 - 0xa0000: type 2 [entry size: 20]
 0xf0000 - 0x100000: type 2 [entry size: 20]
-0x100000 - 0x118000: type 1 [entry size: 20]
-0x118000 - 0x11a000: type 2 [entry size: 20]
+0x100000 - 0x11a000: type 1 [entry size: 20]
 0xfffc0000 - 0x100000000: type 2 [entry size: 20]
 
 mmap start:       0x9000
-mmap end:         0x9090
-real mmap end:    0x9090
+mmap end:         0x9078
+real mmap end:    0x9078
 
 
 === Running test case: mmap.elf -m 2G ===
 
 Lower memory: 639k
-Upper memory: 2096120k
+Upper memory: 2096000k
 
 e820 memory map:
 0x0 - 0x9fc00: type 1 [entry size: 20]
 0x9fc00 - 0xa0000: type 2 [entry size: 20]
 0xf0000 - 0x100000: type 2 [entry size: 20]
-0x100000 - 0x7fffe000: type 1 [entry size: 20]
-0x7fffe000 - 0x80000000: type 2 [entry size: 20]
+0x100000 - 0x7ffe0000: type 1 [entry size: 20]
+0x7ffe0000 - 0x80000000: type 2 [entry size: 20]
 0xfffc0000 - 0x100000000: type 2 [entry size: 20]
 
 mmap start:       0x9000
@@ -58,16 +57,16 @@ real mmap end:    0x9090
 === Running test case: mmap.elf -m 4G ===
 
 Lower memory: 639k
-Upper memory: 3668984k
+Upper memory: 3144576k
 
 e820 memory map:
 0x0 - 0x9fc00: type 1 [entry size: 20]
 0x9fc00 - 0xa0000: type 2 [entry size: 20]
 0xf0000 - 0x100000: type 2 [entry size: 20]
-0x100000 - 0xdfffe000: type 1 [entry size: 20]
-0xdfffe000 - 0xe0000000: type 2 [entry size: 20]
+0x100000 - 0xbffe0000: type 1 [entry size: 20]
+0xbffe0000 - 0xc0000000: type 2 [entry size: 20]
 0xfffc0000 - 0x100000000: type 2 [entry size: 20]
-0x100000000 - 0x120000000: type 1 [entry size: 20]
+0x100000000 - 0x140000000: type 1 [entry size: 20]
 
 mmap start:       0x9000
 mmap end:         0x90a8
@@ -77,16 +76,16 @@ real mmap end:    0x90a8
 === Running test case: mmap.elf -m 8G ===
 
 Lower memory: 639k
-Upper memory: 3668984k
+Upper memory: 3144576k
 
 e820 memory map:
 0x0 - 0x9fc00: type 1 [entry size: 20]
 0x9fc00 - 0xa0000: type 2 [entry size: 20]
 0xf0000 - 0x100000: type 2 [entry size: 20]
-0x100000 - 0xdfffe000: type 1 [entry size: 20]
-0xdfffe000 - 0xe0000000: type 2 [entry size: 20]
+0x100000 - 0xbffe0000: type 1 [entry size: 20]
+0xbffe0000 - 0xc0000000: type 2 [entry size: 20]
 0xfffc0000 - 0x100000000: type 2 [entry size: 20]
-0x100000000 - 0x220000000: type 1 [entry size: 20]
+0x100000000 - 0x240000000: type 1 [entry size: 20]
 
 mmap start:       0x9000
 mmap end:         0x90a8
-- 
1.8.3.1

[Qemu-devel] [PATCH 2/3] multiboot: Fix offset of bootloader name

[Kevin Wolf]

This fixes a bug introduced in commit 5eba5a66 ('Add bootloader name to
multiboot implementation').

The calculation of the bootloader name offset didn't consider space
occupied by module command lines, so some unlucky module got its command
line partially overwritten with a "qemu" string.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/i386/multiboot.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c
index f86d351..1adbe9e 100644
--- a/hw/i386/multiboot.c
+++ b/hw/i386/multiboot.c
@@ -156,6 +156,7 @@ int load_multiboot(FWCfgState *fw_cfg,
     MultibootState mbs;
     uint8_t bootinfo[MBI_SIZE];
     uint8_t *mb_bootinfo_data;
+    uint32_t cmdline_len;
 
     /* Ok, let's see if it is a multiboot image.
        The header is 12x32bit long, so the latest entry may be 8192 - 48. */
@@ -258,27 +259,28 @@ int load_multiboot(FWCfgState *fw_cfg,
     mbs.offset_mbinfo = mbs.mb_buf_size;
 
     /* Calculate space for cmdlines, bootloader name, and mb_mods */
-    mbs.mb_buf_size += strlen(kernel_filename) + 1;
-    mbs.mb_buf_size += strlen(kernel_cmdline) + 1;
-    mbs.mb_buf_size += strlen(bootloader_name) + 1;
+    cmdline_len = strlen(kernel_filename) + 1;
+    cmdline_len += strlen(kernel_cmdline) + 1;
     if (initrd_filename) {
         const char *r = initrd_filename;
-        mbs.mb_buf_size += strlen(r) + 1;
+        cmdline_len += strlen(r) + 1;
         mbs.mb_mods_avail = 1;
         while (*(r = get_opt_value(NULL, 0, r))) {
            mbs.mb_mods_avail++;
            r++;
         }
-        mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
     }
 
+    mbs.mb_buf_size += cmdline_len;
+    mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
+    mbs.mb_buf_size += strlen(bootloader_name) + 1;
+
     mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
 
     /* enlarge mb_buf to hold cmdlines, bootloader, mb-info structs */
     mbs.mb_buf            = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
     mbs.offset_cmdlines   = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
-    mbs.offset_bootloader = mbs.offset_cmdlines + strlen(kernel_filename) + 1 
-                            + strlen(kernel_cmdline) + 1;
+    mbs.offset_bootloader = mbs.offset_cmdlines + cmdline_len;
 
     if (initrd_filename) {
         char *next_initrd, not_last;
-- 
1.8.3.1

[Qemu-devel] [PATCH 3/3] tests/multiboot: Add test for modules

[Kevin Wolf]

This test case is meant to detect corruptions of the Multiboot modules
as well as the multiboot modules list and the module command lines.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 tests/multiboot/Makefile    |  5 ++++-
 tests/multiboot/libc.c      | 12 ++++++++++
 tests/multiboot/libc.h      |  1 +
 tests/multiboot/module.txt  |  1 +
 tests/multiboot/modules.c   | 55 +++++++++++++++++++++++++++++++++++++++++++++
 tests/multiboot/modules.out | 38 +++++++++++++++++++++++++++++++
 tests/multiboot/run_test.sh |  9 +++++++-
 7 files changed, 119 insertions(+), 2 deletions(-)
 create mode 100644 tests/multiboot/module.txt
 create mode 100644 tests/multiboot/modules.c
 create mode 100644 tests/multiboot/modules.out

diff --git a/tests/multiboot/Makefile b/tests/multiboot/Makefile
index 34cdd81..36f01dc 100644
--- a/tests/multiboot/Makefile
+++ b/tests/multiboot/Makefile
@@ -6,11 +6,14 @@ LD=ld
 LDFLAGS=-melf_i386 -T link.ld
 LIBS=$(shell $(CC) $(CCFLAGS) -print-libgcc-file-name)
 
-all: mmap.elf
+all: mmap.elf modules.elf
 
 mmap.elf: start.o mmap.o libc.o
 	$(LD) $(LDFLAGS) -o $@ $^ $(LIBS)
 
+modules.elf: start.o modules.o libc.o
+	$(LD) $(LDFLAGS) -o $@ $^ $(LIBS)
+
 %.o: %.c
 	$(CC) $(CCFLAGS) -c -o $@ $^
 
diff --git a/tests/multiboot/libc.c b/tests/multiboot/libc.c
index 05abbd9..6df9bda 100644
--- a/tests/multiboot/libc.c
+++ b/tests/multiboot/libc.c
@@ -22,6 +22,18 @@
 
 #include "libc.h"
 
+void* memcpy(void *dest, const void *src, int n)
+{
+    char *d = dest;
+    const char *s = src;
+
+    while (n--) {
+        *d++ = *s++;
+    }
+
+    return dest;
+}
+
 static void print_char(char c)
 {
     outb(0xe9, c);
diff --git a/tests/multiboot/libc.h b/tests/multiboot/libc.h
index 80eec5b..04c9922 100644
--- a/tests/multiboot/libc.h
+++ b/tests/multiboot/libc.h
@@ -57,5 +57,6 @@ static inline void outb(uint16_t port, uint8_t data)
 /* Misc functions */
 
 void printf(const char *fmt, ...);
+void* memcpy(void *dest, const void *src, int n);
 
 #endif
diff --git a/tests/multiboot/module.txt b/tests/multiboot/module.txt
new file mode 100644
index 0000000..54c1d27
--- /dev/null
+++ b/tests/multiboot/module.txt
@@ -0,0 +1 @@
+This is a test file that is used as a multiboot module.
diff --git a/tests/multiboot/modules.c b/tests/multiboot/modules.c
new file mode 100644
index 0000000..531601f
--- /dev/null
+++ b/tests/multiboot/modules.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2015 Kevin Wolf <kwolf@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "libc.h"
+#include "multiboot.h"
+
+int test_main(uint32_t magic, struct mb_info *mbi)
+{
+    struct mb_module *mod;
+    unsigned int i;
+
+    (void) magic;
+
+    printf("Module list with %d entries at %x\n",
+           mbi->mods_count, mbi->mods_addr);
+
+    for (i = 0, mod = (struct mb_module*) mbi->mods_addr;
+         i < mbi->mods_count;
+         i++, mod++)
+    {
+        char buf[1024];
+        unsigned int size = mod->mod_end - mod->mod_start;
+
+        printf("[%p] Module: %x - %x (%d bytes) '%s'\n",
+               mod, mod->mod_start, mod->mod_end, size, mod->string);
+
+        /* Print test file, but remove the newline at the end */
+        if (size < sizeof(buf)) {
+            memcpy(buf, (void*) mod->mod_start, size);
+            buf[size - 1] = '\0';
+            printf("         Content: '%s'\n", buf);
+        }
+    }
+
+    return 0;
+}
diff --git a/tests/multiboot/modules.out b/tests/multiboot/modules.out
new file mode 100644
index 0000000..1636708
--- /dev/null
+++ b/tests/multiboot/modules.out
@@ -0,0 +1,38 @@
+
+
+
+=== Running test case: modules.elf  ===
+
+Module list with 0 entries at 102000
+
+
+=== Running test case: modules.elf -initrd module.txt ===
+
+Module list with 1 entries at 102000
+[102000] Module: 103000 - 103038 (56 bytes) 'module.txt'
+         Content: 'This is a test file that is used as a multiboot module.'
+
+
+=== Running test case: modules.elf -initrd module.txt argument ===
+
+Module list with 1 entries at 102000
+[102000] Module: 103000 - 103038 (56 bytes) 'module.txt argument'
+         Content: 'This is a test file that is used as a multiboot module.'
+
+
+=== Running test case: modules.elf -initrd module.txt argument,,with,,commas ===
+
+Module list with 1 entries at 102000
+[102000] Module: 103000 - 103038 (56 bytes) 'module.txt argument,with,commas'
+         Content: 'This is a test file that is used as a multiboot module.'
+
+
+=== Running test case: modules.elf -initrd module.txt,module.txt argument,module.txt ===
+
+Module list with 3 entries at 102000
+[102000] Module: 103000 - 103038 (56 bytes) 'module.txt'
+         Content: 'This is a test file that is used as a multiboot module.'
+[102010] Module: 104000 - 104038 (56 bytes) 'module.txt argument'
+         Content: 'This is a test file that is used as a multiboot module.'
+[102020] Module: 105000 - 105038 (56 bytes) 'module.txt'
+         Content: 'This is a test file that is used as a multiboot module.'
diff --git a/tests/multiboot/run_test.sh b/tests/multiboot/run_test.sh
index 97a9a49..78d7edf 100755
--- a/tests/multiboot/run_test.sh
+++ b/tests/multiboot/run_test.sh
@@ -48,10 +48,17 @@ mmap() {
     run_qemu mmap.elf -m 8G
 }
 
+modules() {
+    run_qemu modules.elf
+    run_qemu modules.elf -initrd module.txt
+    run_qemu modules.elf -initrd "module.txt argument"
+    run_qemu modules.elf -initrd "module.txt argument,,with,,commas"
+    run_qemu modules.elf -initrd "module.txt,module.txt argument,module.txt"
+}
 
 make all
 
-for t in mmap; do
+for t in mmap modules; do
 
     echo > test.log
     $t
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH 2/3] multiboot: Fix offset of bootloader name

[Max Reitz]

On 2015-01-15 at 06:26, Kevin Wolf wrote:
> This fixes a bug introduced in commit 5eba5a66 ('Add bootloader name to
> multiboot implementation').
>
> The calculation of the bootloader name offset didn't consider space
> occupied by module command lines, so some unlucky module got its command
> line partially overwritten with a "qemu" string.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>   hw/i386/multiboot.c | 16 +++++++++-------
>   1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c
> index f86d351..1adbe9e 100644
> --- a/hw/i386/multiboot.c
> +++ b/hw/i386/multiboot.c
> @@ -156,6 +156,7 @@ int load_multiboot(FWCfgState *fw_cfg,
>       MultibootState mbs;
>       uint8_t bootinfo[MBI_SIZE];
>       uint8_t *mb_bootinfo_data;
> +    uint32_t cmdline_len;
>   
>       /* Ok, let's see if it is a multiboot image.
>          The header is 12x32bit long, so the latest entry may be 8192 - 48. */
> @@ -258,27 +259,28 @@ int load_multiboot(FWCfgState *fw_cfg,
>       mbs.offset_mbinfo = mbs.mb_buf_size;
>   
>       /* Calculate space for cmdlines, bootloader name, and mb_mods */
> -    mbs.mb_buf_size += strlen(kernel_filename) + 1;
> -    mbs.mb_buf_size += strlen(kernel_cmdline) + 1;
> -    mbs.mb_buf_size += strlen(bootloader_name) + 1;
> +    cmdline_len = strlen(kernel_filename) + 1;
> +    cmdline_len += strlen(kernel_cmdline) + 1;
>       if (initrd_filename) {
>           const char *r = initrd_filename;
> -        mbs.mb_buf_size += strlen(r) + 1;
> +        cmdline_len += strlen(r) + 1;
>           mbs.mb_mods_avail = 1;
>           while (*(r = get_opt_value(NULL, 0, r))) {
>              mbs.mb_mods_avail++;
>              r++;
>           }
> -        mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
>       }
>   
> +    mbs.mb_buf_size += cmdline_len;
> +    mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
> +    mbs.mb_buf_size += strlen(bootloader_name) + 1;

I would have swapped these two lines to reflect their order in mb_buf, 
but it's fine either way.

> +
>       mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
>   
>       /* enlarge mb_buf to hold cmdlines, bootloader, mb-info structs */
>       mbs.mb_buf            = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
>       mbs.offset_cmdlines   = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
> -    mbs.offset_bootloader = mbs.offset_cmdlines + strlen(kernel_filename) + 1
> -                            + strlen(kernel_cmdline) + 1;
> +    mbs.offset_bootloader = mbs.offset_cmdlines + cmdline_len;
>   
>       if (initrd_filename) {
>           char *next_initrd, not_last;

Reviewed-by: Max Reitz <mreitz@redhat.com>

Re: [Qemu-devel] [PATCH 0/3] multiboot: Fix offset of bootloader name

[Drew DeVault]

On 01/15/2015 04:26 AM, Kevin Wolf wrote:
> This fixes a recent Multiboot load regression (see patch 2) that we
> noticed while hacking on the advent calendar image for December 24.

These changes all look fine to me.

Re: [Qemu-devel] [PATCH 3/3] tests/multiboot: Add test for modules

[Max Reitz]

On 2015-01-15 at 06:26, Kevin Wolf wrote:
> This test case is meant to detect corruptions of the Multiboot modules
> as well as the multiboot modules list and the module command lines.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>   tests/multiboot/Makefile    |  5 ++++-
>   tests/multiboot/libc.c      | 12 ++++++++++
>   tests/multiboot/libc.h      |  1 +
>   tests/multiboot/module.txt  |  1 +
>   tests/multiboot/modules.c   | 55 +++++++++++++++++++++++++++++++++++++++++++++
>   tests/multiboot/modules.out | 38 +++++++++++++++++++++++++++++++
>   tests/multiboot/run_test.sh |  9 +++++++-
>   7 files changed, 119 insertions(+), 2 deletions(-)
>   create mode 100644 tests/multiboot/module.txt
>   create mode 100644 tests/multiboot/modules.c
>   create mode 100644 tests/multiboot/modules.out
>
> diff --git a/tests/multiboot/Makefile b/tests/multiboot/Makefile
> index 34cdd81..36f01dc 100644
> --- a/tests/multiboot/Makefile
> +++ b/tests/multiboot/Makefile
> @@ -6,11 +6,14 @@ LD=ld
>   LDFLAGS=-melf_i386 -T link.ld
>   LIBS=$(shell $(CC) $(CCFLAGS) -print-libgcc-file-name)
>   
> -all: mmap.elf
> +all: mmap.elf modules.elf
>   
>   mmap.elf: start.o mmap.o libc.o
>   	$(LD) $(LDFLAGS) -o $@ $^ $(LIBS)
>   
> +modules.elf: start.o modules.o libc.o
> +	$(LD) $(LDFLAGS) -o $@ $^ $(LIBS)
> +
>   %.o: %.c
>   	$(CC) $(CCFLAGS) -c -o $@ $^
>   
> diff --git a/tests/multiboot/libc.c b/tests/multiboot/libc.c
> index 05abbd9..6df9bda 100644
> --- a/tests/multiboot/libc.c
> +++ b/tests/multiboot/libc.c
> @@ -22,6 +22,18 @@
>   
>   #include "libc.h"
>   
> +void* memcpy(void *dest, const void *src, int n)

This should be "void *memcpy". There are three more occurences of this 
in this patch (see checkpatch output).

> +{
> +    char *d = dest;
> +    const char *s = src;
> +
> +    while (n--) {
> +        *d++ = *s++;
> +    }
> +
> +    return dest;
> +}
> +
>   static void print_char(char c)
>   {
>       outb(0xe9, c);
> diff --git a/tests/multiboot/libc.h b/tests/multiboot/libc.h
> index 80eec5b..04c9922 100644
> --- a/tests/multiboot/libc.h
> +++ b/tests/multiboot/libc.h
> @@ -57,5 +57,6 @@ static inline void outb(uint16_t port, uint8_t data)
>   /* Misc functions */
>   
>   void printf(const char *fmt, ...);
> +void* memcpy(void *dest, const void *src, int n);
>   
>   #endif
> diff --git a/tests/multiboot/module.txt b/tests/multiboot/module.txt
> new file mode 100644
> index 0000000..54c1d27
> --- /dev/null
> +++ b/tests/multiboot/module.txt
> @@ -0,0 +1 @@
> +This is a test file that is used as a multiboot module.
> diff --git a/tests/multiboot/modules.c b/tests/multiboot/modules.c
> new file mode 100644
> index 0000000..531601f
> --- /dev/null
> +++ b/tests/multiboot/modules.c
> @@ -0,0 +1,55 @@
> +/*
> + * Copyright (c) 2015 Kevin Wolf <kwolf@redhat.com>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include "libc.h"
> +#include "multiboot.h"
> +
> +int test_main(uint32_t magic, struct mb_info *mbi)
> +{
> +    struct mb_module *mod;
> +    unsigned int i;
> +
> +    (void) magic;
> +
> +    printf("Module list with %d entries at %x\n",
> +           mbi->mods_count, mbi->mods_addr);
> +
> +    for (i = 0, mod = (struct mb_module*) mbi->mods_addr;
> +         i < mbi->mods_count;
> +         i++, mod++)
> +    {
> +        char buf[1024];
> +        unsigned int size = mod->mod_end - mod->mod_start;
> +
> +        printf("[%p] Module: %x - %x (%d bytes) '%s'\n",
> +               mod, mod->mod_start, mod->mod_end, size, mod->string);
> +
> +        /* Print test file, but remove the newline at the end */
> +        if (size < sizeof(buf)) {
> +            memcpy(buf, (void*) mod->mod_start, size);
> +            buf[size - 1] = '\0';
> +            printf("         Content: '%s'\n", buf);
> +        }
> +    }
> +
> +    return 0;
> +}
> diff --git a/tests/multiboot/modules.out b/tests/multiboot/modules.out
> new file mode 100644
> index 0000000..1636708
> --- /dev/null
> +++ b/tests/multiboot/modules.out
> @@ -0,0 +1,38 @@
> +
> +
> +
> +=== Running test case: modules.elf  ===
> +
> +Module list with 0 entries at 102000
> +
> +
> +=== Running test case: modules.elf -initrd module.txt ===
> +
> +Module list with 1 entries at 102000

"1 entries"? Critical! ;-)

Reviewed-by: Max Reitz <mreitz@redhat.com>

I cannot give an R-b for the first patch simply because I don't have 
enough RAM to test it.

Max

Re: [Qemu-devel] [PATCH 0/3] multiboot: Fix offset of bootloader name

[Paolo Bonzini]

On 15/01/2015 12:26, Kevin Wolf wrote:
> This fixes a recent Multiboot load regression (see patch 2) that we
> noticed while hacking on the advent calendar image for December 24.
> 
> Kevin Wolf (3):
>   tests/multiboot: Update reference output
>   multiboot: Fix offset of bootloader name
>   tests/multiboot: Add test for modules
> 
>  hw/i386/multiboot.c         | 16 +++++++------
>  tests/multiboot/Makefile    |  5 ++++-
>  tests/multiboot/libc.c      | 12 ++++++++++
>  tests/multiboot/libc.h      |  1 +
>  tests/multiboot/mmap.out    | 37 +++++++++++++++---------------
>  tests/multiboot/module.txt  |  1 +
>  tests/multiboot/modules.c   | 55 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/multiboot/modules.out | 38 +++++++++++++++++++++++++++++++
>  tests/multiboot/run_test.sh |  9 +++++++-
>  9 files changed, 146 insertions(+), 28 deletions(-)
>  create mode 100644 tests/multiboot/module.txt
>  create mode 100644 tests/multiboot/modules.c
>  create mode 100644 tests/multiboot/modules.out
> 

Thanks, I'll put this in the next pull request.

Paolo