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

[Anthony Liguori <anthony@codemonkey.ws>]

On 07/23/2011 03:19 PM, Jordan Justen wrote:
> On Sat, Jul 23, 2011 at 08:51, Anthony Liguori<anthony@codemonkey.ws>  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.

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<jordan.l.justen@intel.com>
>>> Reviewed-by: Aurelien Jarno<aurelien@aurel32.net>
>>
>>
>>
>>> ---
>>>   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);
>>>
>>
>>
>>
>