Re: [Qemu-devel] [PATCH] Add bootloader name to multiboot implementation

[Drew DeVault <sircmpwn@gmail.com>]

cc-ing a few people I found in the blame for the relevant files. Mind 
taking a look at this patch?

Thanks!

On 11/04/2014 12:49 PM, Drew DeVault wrote:
> Ping: http://patchwork.ozlabs.org/patch/404885/
>
> Does anyone know someone I can cc on this? This part of the code doesn't
> have a dedicated maintainer.
>
> On 10/29/2014 11:52 PM, Drew DeVault wrote:
>> The name is set to "qemu".
>>
>> Signed-off-by: Drew DeVault <sir@cmpwn.com>
>> ---
>> For the future, it may be useful to add a command line flag for
>> setting this to
>> some user-specified value. I also considered naming it
>> "qemu-system-i386" or
>> "qemu-system-x86_64" (as appropriate), but couldn't find an easy way
>> to get
>> those strings and decided it didn't matter.
>>
>>   hw/i386/multiboot.c | 32 +++++++++++++++++++++++++++-----
>>   1 file changed, 27 insertions(+), 5 deletions(-)
>>
>> diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c
>> index 985ca1e..f86d351 100644
>> --- a/hw/i386/multiboot.c
>> +++ b/hw/i386/multiboot.c
>> @@ -54,6 +54,7 @@ enum {
>>       MBI_MODS_COUNT  = 20,
>>       MBI_MODS_ADDR   = 24,
>>       MBI_MMAP_ADDR   = 48,
>> +    MBI_BOOTLOADER  = 64,
>>
>>       MBI_SIZE        = 88,
>>
>> @@ -74,6 +75,7 @@ enum {
>>       MULTIBOOT_FLAGS_CMDLINE     = 1 << 2,
>>       MULTIBOOT_FLAGS_MODULES     = 1 << 3,
>>       MULTIBOOT_FLAGS_MMAP        = 1 << 6,
>> +    MULTIBOOT_FLAGS_BOOTLOADER  = 1 << 9,
>>   };
>>
>>   typedef struct {
>> @@ -87,6 +89,8 @@ typedef struct {
>>       hwaddr offset_mbinfo;
>>       /* offset in buffer for cmdlines in bytes */
>>       hwaddr offset_cmdlines;
>> +    /* offset in buffer for bootloader name in bytes */
>> +    hwaddr offset_bootloader;
>>       /* offset of modules in bytes */
>>       hwaddr offset_mods;
>>       /* available slots for mb modules infos */
>> @@ -95,6 +99,8 @@ typedef struct {
>>       int mb_mods_count;
>>   } MultibootState;
>>
>> +const char *bootloader_name = "qemu";
>> +
>>   static uint32_t mb_add_cmdline(MultibootState *s, const char *cmdline)
>>   {
>>       hwaddr p = s->offset_cmdlines;
>> @@ -105,6 +111,16 @@ static uint32_t mb_add_cmdline(MultibootState *s,
>> const char *cmdline)
>>       return s->mb_buf_phys + p;
>>   }
>>
>> +static uint32_t mb_add_bootloader(MultibootState *s, const char
>> *bootloader)
>> +{
>> +    hwaddr p = s->offset_bootloader;
>> +    char *b = (char *)s->mb_buf + p;
>> +
>> +    memcpy(b, bootloader, strlen(bootloader) + 1);
>> +    s->offset_bootloader += strlen(b) + 1;
>> +    return s->mb_buf_phys + p;
>> +}
>> +
>>   static void mb_add_mod(MultibootState *s,
>>                          hwaddr start, hwaddr end,
>>                          hwaddr cmdline_phys)
>> @@ -241,9 +257,10 @@ int load_multiboot(FWCfgState *fw_cfg,
>>       mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_kernel_size);
>>       mbs.offset_mbinfo = mbs.mb_buf_size;
>>
>> -    /* Calculate space for cmdlines and mb_mods */
>> +    /* 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;
>>       if (initrd_filename) {
>>           const char *r = initrd_filename;
>>           mbs.mb_buf_size += strlen(r) + 1;
>> @@ -257,9 +274,11 @@ int load_multiboot(FWCfgState *fw_cfg,
>>
>>       mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
>>
>> -    /* enlarge mb_buf to hold cmdlines and 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;
>> +    /* 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;
>>
>>       if (initrd_filename) {
>>           char *next_initrd, not_last;
>> @@ -306,6 +325,8 @@ int load_multiboot(FWCfgState *fw_cfg,
>>                kernel_filename, kernel_cmdline);
>>       stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
>>
>> +    stl_p(bootinfo + MBI_BOOTLOADER, mb_add_bootloader(&mbs,
>> bootloader_name));
>> +
>>       stl_p(bootinfo + MBI_MODS_ADDR,  mbs.mb_buf_phys +
>> mbs.offset_mbinfo);
>>       stl_p(bootinfo + MBI_MODS_COUNT, mbs.mb_mods_count); /*
>> mods_count */
>>
>> @@ -314,7 +335,8 @@ int load_multiboot(FWCfgState *fw_cfg,
>>                                   | MULTIBOOT_FLAGS_BOOT_DEVICE
>>                                   | MULTIBOOT_FLAGS_CMDLINE
>>                                   | MULTIBOOT_FLAGS_MODULES
>> -                                | MULTIBOOT_FLAGS_MMAP);
>> +                                | MULTIBOOT_FLAGS_MMAP
>> +                                | MULTIBOOT_FLAGS_BOOTLOADER);
>>       stl_p(bootinfo + MBI_BOOT_DEVICE, 0x8000ffff); /* XXX: use the
>> -boot switch? */
>>       stl_p(bootinfo + MBI_MMAP_ADDR,   ADDR_E820_MAP);
>>
>>