Re: [Qemu-devel] [RFC] extensions to the -m memory option

[Peter Crosthwaite]

On Sat, May 30, 2015 at 3:32 AM, Paolo Bonzini <address@hidden> wrote:
>
>
> On 30/05/2015 11:55, Peter Crosthwaite wrote:
>> I think the same is true of NOR.
>
> NOR is sized according to the capacity of its backing file, at least in
> the PC case.
>

So that might be the exception to the rule. I assume that is this (pc_sysfw.c):

        snprintf(name, sizeof name, "system.flash%d", unit);
        system_flash = pflash_cfi01_register(phys_addr, NULL /* qdev */, name,
                                             size, blk, sector_size,
                                             size >> sector_bits,
                                             1      /* width */,
                                             0x0000 /* id0 */,
                                             0x0000 /* id1 */,
                                             0x0000 /* id2 */,
                                             0x0000 /* id3 */,
                                             0      /* be */);

This ID fields are 0'd out and a generic flash is created matching the
blk dev geometry. So this does what you says it does.

A bit of grepping around, there are a good number of embedded boards
(ARM is heavily represented) where the board specifies the flash
specifically. Here is one for versatilepb:

hw/arm/versatilepb.c:#define VERSATILE_FLASH_SIZE (64 * 1024 * 1024)

hw/arm/versatilepb.c:    if
(!pflash_cfi01_register(VERSATILE_FLASH_ADDR, NULL, "versatile.flash",
hw/arm/versatilepb.c-                          VERSATILE_FLASH_SIZE,
hw/arm/versatilepb.c-                          dinfo ?
blk_by_legacy_dinfo(dinfo) : NULL,
hw/arm/versatilepb.c-                          VERSATILE_FLASH_SECT_SIZE,
hw/arm/versatilepb.c-                          VERSATILE_FLASH_SIZE /
VERSATILE_FLASH_SECT_SIZE,
hw/arm/versatilepb.c-                          4, 0x0089, 0x0018,
0x0000, 0x0, 0)) {

Vexpress does something very similar but using QOM setters instead.
The IDs are set to something very specific indicating a chosen part
rather than a generic pflash.

Consequently we have the mixed semantic of blk sometimes dictating the
device size and other times not. For ARM, it is generally the not
case.

Regards,
Peter

> Paolo
>