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

[Anthony Liguori <anthony@codemonkey.ws>]

On 07/23/2011 05:06 PM, Jordan Justen wrote:
> On Sat, Jul 23, 2011 at 14:25, Anthony Liguori<anthony@codemonkey.ws>  wrote:
>> 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.
>
> 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?

No.  There should be a flash device, pflash index 0 is fine, but it 
should be mapped under 4GB and also in the legacy BIOS space.

This is the PC firmware flash.  By default it should be read-only and it 
should be created by using ${prefix}/share/bios.bin.  But it should be 
possible to override both the filename and the read-only flag.

In terms of other flash devices, I don't think it's that simple.  Flash 
is tied to the mobo layout so I don't think index > 0 really makes sense 
unless you allow a specific mapping address.  I doubt that's terribly 
useful.

Regards,

Anthony Liguori

>
> 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<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);
>>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>