Re: [Qemu-devel] [PATCH v8 2/5] loader: All a custom SddressSpace when loading ROMs

[Alistair Francis]

On Tue, Jul 12, 2016 at 9:56 AM, Peter Maydell <address@hidden> wrote:
> On 2 July 2016 at 02:07, Alistair Francis <address@hidden> wrote:
>> When loading ROMs allow the caller to specify an AddressSpace to use for
>> the load.
>>
>> Signed-off-by: Alistair Francis <address@hidden>
>> ---
>> V8:
>>  - Introduce an RFC version of AddressSpace loading support
>>
>>  hw/core/loader.c     | 18 ++++++++++++------
>>  include/hw/elf_ops.h |  2 +-
>>  include/hw/loader.h  | 10 ++++++----
>>  3 files changed, 19 insertions(+), 11 deletions(-)
>>
>> diff --git a/hw/core/loader.c b/hw/core/loader.c
>> index 53e0e41..fcbcfbf 100644
>> --- a/hw/core/loader.c
>> +++ b/hw/core/loader.c
>> @@ -777,6 +777,7 @@ struct Rom {
>>
>>      uint8_t *data;
>>      MemoryRegion *mr;
>> +    AddressSpace *as;
>>      int isrom;
>>      char *fw_dir;
>>      char *fw_file;
>> @@ -833,7 +834,8 @@ static void *rom_set_mr(Rom *rom, Object *owner, const 
>> char *name)
>>
>>  int rom_add_file(const char *file, const char *fw_dir,
>>                   hwaddr addr, int32_t bootindex,
>> -                 bool option_rom, MemoryRegion *mr)
>> +                 bool option_rom, MemoryRegion *mr,
>> +                 AddressSpace *as)
>
> We seem to add this argument to the function but never use it?

I have fixed that.

>
> I think specifying both mr and as should be an error.

Agreed, it is now an error.

>
>>  {
>>      MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
>>      Rom *rom;
>> @@ -969,7 +971,7 @@ MemoryRegion *rom_add_blob(const char *name, const void 
>> *blob, size_t len,
>>   * memory ownership of "data", so we don't have to allocate and copy the 
>> buffer.
>>   */
>>  int rom_add_elf_program(const char *name, void *data, size_t datasize,
>> -                        size_t romsize, hwaddr addr)
>> +                        size_t romsize, hwaddr addr, AddressSpace *as)
>>  {
>>      Rom *rom;
>>
>> @@ -979,18 +981,19 @@ int rom_add_elf_program(const char *name, void *data, 
>> size_t datasize,
>>      rom->datasize = datasize;
>>      rom->romsize  = romsize;
>>      rom->data     = data;
>> +    rom->as       = as;
>>      rom_insert(rom);
>>      return 0;
>>  }
>>
>>  int rom_add_vga(const char *file)
>>  {
>> -    return rom_add_file(file, "vgaroms", 0, -1, true, NULL);
>> +    return rom_add_file(file, "vgaroms", 0, -1, true, NULL, NULL);
>>  }
>>
>>  int rom_add_option(const char *file, int32_t bootindex)
>>  {
>> -    return rom_add_file(file, "genroms", 0, bootindex, true, NULL);
>> +    return rom_add_file(file, "genroms", 0, bootindex, true, NULL, NULL);
>>  }
>>
>>  static void rom_reset(void *unused)
>> @@ -1008,7 +1011,8 @@ static void rom_reset(void *unused)
>>              void *host = memory_region_get_ram_ptr(rom->mr);
>>              memcpy(host, rom->data, rom->datasize);
>>          } else {
>> -            cpu_physical_memory_write_rom(&address_space_memory,
>> +            cpu_physical_memory_write_rom(rom->as ? rom->as :
>> +                                                    &address_space_memory,
>>                                            rom->addr, rom->data, 
>> rom->datasize);
>>          }
>>          if (rom->isrom) {
>> @@ -1031,12 +1035,13 @@ int rom_check_and_register_reset(void)
>>      hwaddr addr = 0;
>>      MemoryRegionSection section;
>>      Rom *rom;
>> +    AddressSpace *as = NULL;
>>
>>      QTAILQ_FOREACH(rom, &roms, next) {
>>          if (rom->fw_file) {
>>              continue;
>>          }
>> -        if (addr > rom->addr) {
>> +        if ((addr > rom->addr) && (as == rom->as)) {
>>              fprintf(stderr, "rom: requested regions overlap "
>>                      "(rom %s. free=0x" TARGET_FMT_plx
>>                      ", addr=0x" TARGET_FMT_plx ")\n",
>> @@ -1048,6 +1053,7 @@ int rom_check_and_register_reset(void)
>>          section = memory_region_find(get_system_memory(), rom->addr, 1);
>
> (An unrelated bug but I've just noticed that this code doesn't
> make sense for ROMs which go into a memory region rather than
> at an address in the system address space.)

I'll add a patch to fix this as well.

>
>>          rom->isrom = int128_nz(section.size) && 
>> memory_region_is_rom(section.mr);
>>          memory_region_unref(section.mr);
>> +        as = rom->as;
>>      }
>
> I don't think this attempt at checking is going to actually
> catch all the overlap cases if you allow multiple address
> spaces. The rom_insert() code orders roms in this
> list purely by load address, so you could get cases like
>  [AS A, 0..0x1000], [AS B, 0..0x1000], [AS A, 0x500..0x1000]
> where entries 1 and 3 overlap but won't get caught.
> You probably need to order the list by AS first and then
> by address, and then adjust this code accordingly.

I have changed the ordering now to be by AddressSpace and load address.

Thanks,

Alistair

>
>>      qemu_register_reset(rom_reset, NULL);
>>      roms_loaded = 1;
>> diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h
>> index db70c11..1339677 100644
>> --- a/include/hw/elf_ops.h
>> +++ b/include/hw/elf_ops.h
>> @@ -405,7 +405,7 @@ static int glue(load_elf, SZ)(const char *name, int fd,
>>              snprintf(label, sizeof(label), "phdr #%d: %s", i, name);
>>
>>              /* rom_add_elf_program() seize the ownership of 'data' */
>> -            rom_add_elf_program(label, data, file_size, mem_size, addr);
>> +            rom_add_elf_program(label, data, file_size, mem_size, addr, 
>> NULL);
>>
>>              total_size += mem_size;
>>              if (addr < low)
>> diff --git a/include/hw/loader.h b/include/hw/loader.h
>> index 4879b63..18eb0f2 100644
>> --- a/include/hw/loader.h
>> +++ b/include/hw/loader.h
>> @@ -118,14 +118,14 @@ extern bool rom_file_has_mr;
>>
>>  int rom_add_file(const char *file, const char *fw_dir,
>>                   hwaddr addr, int32_t bootindex,
>> -                 bool option_rom, MemoryRegion *mr);
>> +                 bool option_rom, MemoryRegion *mr, AddressSpace *as);
>>  MemoryRegion *rom_add_blob(const char *name, const void *blob, size_t len,
>>                             size_t max_len, hwaddr addr,
>>                             const char *fw_file_name,
>>                             FWCfgReadCallback fw_callback,
>>                             void *callback_opaque);
>>  int rom_add_elf_program(const char *name, void *data, size_t datasize,
>> -                        size_t romsize, hwaddr addr);
>> +                        size_t romsize, hwaddr addr, AddressSpace *as);
>>  int rom_check_and_register_reset(void);
>>  void rom_set_fw(FWCfgState *f);
>>  void rom_set_order_override(int order);
>> @@ -135,11 +135,13 @@ void *rom_ptr(hwaddr addr);
>>  void hmp_info_roms(Monitor *mon, const QDict *qdict);
>>
>>  #define rom_add_file_fixed(_f, _a, _i)          \
>> -    rom_add_file(_f, NULL, _a, _i, false, NULL)
>> +    rom_add_file(_f, NULL, _a, _i, false, NULL, NULL)
>>  #define rom_add_blob_fixed(_f, _b, _l, _a)      \
>>      rom_add_blob(_f, _b, _l, _l, _a, NULL, NULL, NULL)
>>  #define rom_add_file_mr(_f, _mr, _i)            \
>> -    rom_add_file(_f, NULL, 0, _i, false, _mr)
>> +    rom_add_file(_f, NULL, 0, _i, false, _mr, NULL)
>> +#define rom_add_file_as(_f, _as, _i)            \
>> +    rom_add_file(_f, NULL, 0, _i, false, NULL, _as)
>>
>>  #define PC_ROM_MIN_VGA     0xc0000
>>  #define PC_ROM_MIN_OPTION  0xc8000
>> --
>> 2.7.4
>>
>
> thanks
> -- PMM
>