Re: [Qemu-devel] [PATCH v4] hw/pc: Support system flash memory with -pflash parameter

[Jordan Justen]

On Sat, Jul 23, 2011 at 14:25, Anthony Liguori <address@hidden> wrote:
> On 07/23/2011 03:19 PM, Jordan Justen wrote:
>>
>> On Sat, Jul 23, 2011 at 08:51, Anthony Liguori<address@hidden>
>>  wrote:
>>>
>>> On 07/08/2011 02:37 PM, Jordan Justen wrote:
>>>>
>>>> If -pflash is specified and -bios is specified then pflash will
>>>> be mapped just below the system rom using hw/pflash_cfi01.c.
>>>>
>>>> If -pflash is specified on the command line, but -bios is
>>>> not specified, then 'bios.bin' will NOT be loaded, and
>>>> instead the -pflash flash image will be mapped just below
>>>> 4GB in place of the normal rom image.
>>>
>>> This is way too tied to the pc platform to be this generic.
>>>
>>> I think a better approach would be to default to having unit=0 of
>>> IF_PFLASH
>>> default to a read-only BDS that points to bios.bin.  -bios would just be
>>> a
>>> short cut to use a different file name but you should be able to override
>>> with -drive too.
>>>
>>> And to really simplify things, you could add a readonly flag to -bios
>>> such
>>> that you could do:
>>>
>>> -bios foo.img,readonly=off
>>>
>>> Which is what I think you're looking for semantically.
>>
>> There seemed to be some feedback on the list interested in preserving
>> a read-only firmware, and just adding a flash region.
>>
>> So, for example, the firmware could be read from a common system
>> location like is generally done with bios.bin today, and VM instance
>> specific flash region could still be added.
>
> You can have multiple flash regions.

So, is your recommendation that we support N pflash images in
x86/x86-64?  Instance/index 0 is mapped just under 4GB, and the rest
follow below this?

This seems like a good plan, although I can't see a usage for more
than 2 instances.

-Jordan

> You're introducing two modes.  In one mode, we emulate a flash device and
> expose it for the BIOS ROM.  In the second mode, we don't emulate a device
> but we expose the BIOS ROM based on a file in a shared read-only location.
>
> I'm suggesting always emulating a flash device, but by default make the
> device read-only and have it be loaded from a file in a shared read-only
> location.
>
> That means we have a single code path and a consistent view from a
> management tooling perspective.  IOW, management tools will always see that
> there is a BIOS block device, and they need to worry about making sure that
> BIOS block device is there.
>
>>
>> If the entire firmware is moved to a separate VM instance specific
>> flash, then firmware update also gets complicated.  It is no longer
>> just a matter of updating the qemu firmware package in your distro's
>> package management system.
>
> I think the bit your misunderstanding is that you should default the
> firmware to be created from a common file as a read-only device.
>
> Regards,
>
> Anthony Liguori
>
>>
>> What about taking your idea, but adding a second drive that would be
>> mapped just below the 1st if it is specified with -drive?
>>
>> Thanks,
>>
>> -Jordan
>>
>>>
>>> Regards,
>>>
>>> Anthony Liguori
>>>
>>>>
>>>> Signed-off-by: Jordan Justen<address@hidden>
>>>> Reviewed-by: Aurelien Jarno<address@hidden>
>>>
>>>
>>>
>>>> ---
>>>>  default-configs/i386-softmmu.mak   |    1 +
>>>>  default-configs/x86_64-softmmu.mak |    1 +
>>>>  hw/pc.c                            |  161
>>>> +++++++++++++++++++++++++++---------
>>>>  3 files changed, 125 insertions(+), 38 deletions(-)
>>>>
>>>> diff --git a/default-configs/i386-softmmu.mak
>>>> b/default-configs/i386-softmmu.mak
>>>> index 55589fa..8697cd4 100644
>>>> --- a/default-configs/i386-softmmu.mak
>>>> +++ b/default-configs/i386-softmmu.mak
>>>> @@ -21,3 +21,4 @@ CONFIG_PIIX_PCI=y
>>>>  CONFIG_SOUND=y
>>>>  CONFIG_HPET=y
>>>>  CONFIG_APPLESMC=y
>>>> +CONFIG_PFLASH_CFI01=y
>>>> diff --git a/default-configs/x86_64-softmmu.mak
>>>> b/default-configs/x86_64-softmmu.mak
>>>> index 8895028..eca9284 100644
>>>> --- a/default-configs/x86_64-softmmu.mak
>>>> +++ b/default-configs/x86_64-softmmu.mak
>>>> @@ -21,3 +21,4 @@ CONFIG_PIIX_PCI=y
>>>>  CONFIG_SOUND=y
>>>>  CONFIG_HPET=y
>>>>  CONFIG_APPLESMC=y
>>>> +CONFIG_PFLASH_CFI01=y
>>>> diff --git a/hw/pc.c b/hw/pc.c
>>>> index a3e8539..e25354f 100644
>>>> --- a/hw/pc.c
>>>> +++ b/hw/pc.c
>>>> @@ -41,6 +41,7 @@
>>>>  #include "sysemu.h"
>>>>  #include "blockdev.h"
>>>>  #include "ui/qemu-spice.h"
>>>> +#include "flash.h"
>>>>
>>>>  /* output Bochs bios info messages */
>>>>  //#define DEBUG_BIOS
>>>> @@ -957,70 +958,154 @@ void pc_cpus_init(const char *cpu_model)
>>>>      }
>>>>  }
>>>>
>>>> -void pc_memory_init(const char *kernel_filename,
>>>> -                    const char *kernel_cmdline,
>>>> -                    const char *initrd_filename,
>>>> -                    ram_addr_t below_4g_mem_size,
>>>> -                    ram_addr_t above_4g_mem_size)
>>>> +static void pc_isa_bios_init(ram_addr_t ram_offset, int ram_size)
>>>>  {
>>>> -    char *filename;
>>>> -    int ret, linux_boot, i;
>>>> -    ram_addr_t ram_addr, bios_offset, option_rom_offset;
>>>> -    int bios_size, isa_bios_size;
>>>> -    void *fw_cfg;
>>>> -
>>>> -    linux_boot = (kernel_filename != NULL);
>>>> +    int isa_bios_size;
>>>>
>>>> -    /* allocate RAM */
>>>> -    ram_addr = qemu_ram_alloc(NULL, "pc.ram",
>>>> -                              below_4g_mem_size + above_4g_mem_size);
>>>> -    cpu_register_physical_memory(0, 0xa0000, ram_addr);
>>>> -    cpu_register_physical_memory(0x100000,
>>>> -                 below_4g_mem_size - 0x100000,
>>>> -                 ram_addr + 0x100000);
>>>> -    if (above_4g_mem_size>    0) {
>>>> -        cpu_register_physical_memory(0x100000000ULL, above_4g_mem_size,
>>>> -                                     ram_addr + below_4g_mem_size);
>>>> +    /* map the last 128KB of the BIOS in ISA space */
>>>> +    isa_bios_size = ram_size;
>>>> +    if (isa_bios_size>    (128 * 1024)) {
>>>> +        isa_bios_size = 128 * 1024;
>>>>      }
>>>> +    ram_offset = ram_offset + ram_size - isa_bios_size;
>>>> +    cpu_register_physical_memory(0x100000 - isa_bios_size,
>>>> +                                 isa_bios_size,
>>>> +                                 ram_offset | IO_MEM_ROM);
>>>> +}
>>>> +
>>>> +static int pc_system_rom_init(void)
>>>> +{
>>>> +    int ret;
>>>> +    int bios_size;
>>>> +    ram_addr_t bios_offset;
>>>> +    char *filename;
>>>>
>>>>      /* BIOS load */
>>>> -    if (bios_name == NULL)
>>>> +    if (bios_name == NULL) {
>>>>          bios_name = BIOS_FILENAME;
>>>> +    }
>>>>      filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
>>>>      if (filename) {
>>>>          bios_size = get_image_size(filename);
>>>>      } else {
>>>>          bios_size = -1;
>>>>      }
>>>> -    if (bios_size<= 0 ||
>>>> -        (bios_size % 65536) != 0) {
>>>> -        goto bios_error;
>>>> +
>>>> +    if (bios_size<= 0 || (bios_size % 65536) != 0) {
>>>> +        ret = -1;
>>>> +    } else {
>>>> +        bios_offset = qemu_ram_alloc(NULL, "pc.bios", bios_size);
>>>> +        ret = rom_add_file_fixed(bios_name, (uint32_t)(-bios_size),
>>>> -1);
>>>>      }
>>>> -    bios_offset = qemu_ram_alloc(NULL, "pc.bios", bios_size);
>>>> -    ret = rom_add_file_fixed(bios_name, (uint32_t)(-bios_size), -1);
>>>> +
>>>>      if (ret != 0) {
>>>> -    bios_error:
>>>>          fprintf(stderr, "qemu: could not load PC BIOS '%s'\n",
>>>> bios_name);
>>>>          exit(1);
>>>>      }
>>>> +
>>>>      if (filename) {
>>>>          qemu_free(filename);
>>>>      }
>>>> -    /* map the last 128KB of the BIOS in ISA space */
>>>> -    isa_bios_size = bios_size;
>>>> -    if (isa_bios_size>    (128 * 1024))
>>>> -        isa_bios_size = 128 * 1024;
>>>> -    cpu_register_physical_memory(0x100000 - isa_bios_size,
>>>> -                                 isa_bios_size,
>>>> -                                 (bios_offset + bios_size -
>>>> isa_bios_size) | IO_MEM_ROM);
>>>>
>>>> -    option_rom_offset = qemu_ram_alloc(NULL, "pc.rom", PC_ROM_SIZE);
>>>> -    cpu_register_physical_memory(PC_ROM_MIN_VGA, PC_ROM_SIZE,
>>>> option_rom_offset);
>>>> +    pc_isa_bios_init(bios_offset, bios_size);
>>>>
>>>>      /* map all the bios at the top of memory */
>>>>      cpu_register_physical_memory((uint32_t)(-bios_size),
>>>>                                   bios_size, bios_offset | IO_MEM_ROM);
>>>>
>>>> +    return bios_size;
>>>> +}
>>>> +
>>>> +static void pc_system_flash_init(DriveInfo *pflash_drv, int rom_size)
>>>> +{
>>>> +    BlockDriverState *bdrv;
>>>> +    int64_t size;
>>>> +    target_phys_addr_t phys_addr;
>>>> +    ram_addr_t addr;
>>>> +    int sector_bits, sector_size;
>>>> +
>>>> +    bdrv = NULL;
>>>> +
>>>> +    bdrv = pflash_drv->bdrv;
>>>> +    size = bdrv_getlength(pflash_drv->bdrv);
>>>> +    sector_bits = 12;
>>>> +    sector_size = 1<<    sector_bits;
>>>> +
>>>> +    if ((size % sector_size) != 0) {
>>>> +        fprintf(stderr,
>>>> +                "qemu: -pflash size must be a multiple of 0x%x\n",
>>>> +                sector_size);
>>>> +        exit(1);
>>>> +    }
>>>> +
>>>> +    phys_addr = 0x100000000ULL - rom_size - size;
>>>> +    addr = qemu_ram_alloc(NULL, "system.flash", size);
>>>> +    DPRINTF("flash addr: 0x%lx\n", (int64_t)phys_addr);
>>>> +    pflash_cfi01_register(phys_addr, addr, bdrv,
>>>> +                          sector_size, size>>    sector_bits,
>>>> +                          4, 0x0000, 0x0000, 0x0000, 0x0000, 0);
>>>> +
>>>> +    if (rom_size == 0) {
>>>> +        pc_isa_bios_init(addr, size);
>>>> +    }
>>>> +}
>>>> +
>>>> +static void pc_system_firmware_init(void)
>>>> +{
>>>> +    int flash_present, rom_present;
>>>> +    int rom_size;
>>>> +    DriveInfo *pflash_drv;
>>>> +
>>>> +    pflash_drv = drive_get(IF_PFLASH, 0, 0);
>>>> +    flash_present = (pflash_drv != NULL);
>>>> +
>>>> +    /* Load rom if -bios is used or if -pflash is not used */
>>>> +    rom_present = ((bios_name != NULL) || !flash_present);
>>>> +
>>>> +    /* If rom is present, then it is mapped just below 4GB */
>>>> +    if (rom_present) {
>>>> +        rom_size = pc_system_rom_init();
>>>> +    } else {
>>>> +        rom_size = 0;
>>>> +    }
>>>> +
>>>> +    /* If flash is present, then it is mapped just below the rom, or
>>>> +     * just below 4GB when rom is not present. */
>>>> +    if (flash_present) {
>>>> +        pc_system_flash_init(pflash_drv, rom_size);
>>>> +    }
>>>> +}
>>>> +
>>>> +void pc_memory_init(const char *kernel_filename,
>>>> +                    const char *kernel_cmdline,
>>>> +                    const char *initrd_filename,
>>>> +                    ram_addr_t below_4g_mem_size,
>>>> +                    ram_addr_t above_4g_mem_size)
>>>> +{
>>>> +    int linux_boot, i;
>>>> +    ram_addr_t ram_addr, option_rom_offset;
>>>> +    void *fw_cfg;
>>>> +
>>>> +    linux_boot = (kernel_filename != NULL);
>>>> +
>>>> +    /* allocate RAM */
>>>> +    ram_addr = qemu_ram_alloc(NULL, "pc.ram",
>>>> +                              below_4g_mem_size + above_4g_mem_size);
>>>> +    cpu_register_physical_memory(0, 0xa0000, ram_addr);
>>>> +    cpu_register_physical_memory(0x100000,
>>>> +                 below_4g_mem_size - 0x100000,
>>>> +                 ram_addr + 0x100000);
>>>> +    if (above_4g_mem_size>    0) {
>>>> +        cpu_register_physical_memory(0x100000000ULL, above_4g_mem_size,
>>>> +                                     ram_addr + below_4g_mem_size);
>>>> +    }
>>>> +
>>>> +    /* Initialize ROM or flash ranges for PC firmware */
>>>> +    pc_system_firmware_init();
>>>> +
>>>> +    option_rom_offset = qemu_ram_alloc(NULL, "pc.rom", PC_ROM_SIZE);
>>>> +    cpu_register_physical_memory(PC_ROM_MIN_VGA, PC_ROM_SIZE,
>>>> option_rom_offset);
>>>> +
>>>>      fw_cfg = bochs_bios_init();
>>>>      rom_set_fw(fw_cfg);
>>>>
>>>
>>>
>>>
>>
>
>