On Fri, Nov 28, 2014 at 12:18:27AM +0100, Laszlo Ersek wrote: > fw_cfg already supports exposure over MMIO (used in ppc/mac_newworld.c, > ppc/mac_oldworld.c, sparc/sun4m.c); we can easily add it to the "virt" > board. > > The mmio register block of fw_cfg is advertized in the device tree. As > base address we pick 0x09020000, which conforms to the comment preceding > "a15memmap": it falls in the miscellaneous device I/O range 128MB..256MB, > and it is aligned at 64KB. > > fw_cfg automatically exports a number of files to the guest; for example, > "bootorder" (see fw_cfg_machine_reset()). > > Signed-off-by: Laszlo Ersek <ler...@redhat.com> > --- > hw/arm/virt.c | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/hw/arm/virt.c b/hw/arm/virt.c > index 314e55b..070bd34 100644 > --- a/hw/arm/virt.c > +++ b/hw/arm/virt.c > @@ -68,6 +68,7 @@ enum { > VIRT_UART, > VIRT_MMIO, > VIRT_RTC, > + VIRT_FW_CFG, > }; > > typedef struct MemMapEntry { > @@ -107,6 +108,7 @@ static const MemMapEntry a15memmap[] = { > [VIRT_GIC_CPU] = { 0x08010000, 0x00010000 }, > [VIRT_UART] = { 0x09000000, 0x00001000 }, > [VIRT_RTC] = { 0x09010000, 0x00001000 }, > + [VIRT_FW_CFG] = { 0x09020000, FW_CFG_SIZE + FW_CFG_DATA_SIZE }, > [VIRT_MMIO] = { 0x0a000000, 0x00000200 }, > /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that size > */ > /* 0x10000000 .. 0x40000000 reserved for PCI */ > @@ -519,6 +521,23 @@ static void create_flash(const VirtBoardInfo *vbi) > g_free(nodename); > } > > +static void create_fw_cfg(const VirtBoardInfo *vbi) > +{ > + hwaddr base = vbi->memmap[VIRT_FW_CFG].base; > + char *nodename; > + > + fw_cfg_init(0, 0, base, base + FW_CFG_SIZE); > + > + nodename = g_strdup_printf("/fw-cfg@%" PRIx64, base); > + qemu_fdt_add_subnode(vbi->fdt, nodename); > + qemu_fdt_setprop_string(vbi->fdt, nodename, > + "compatible", "fw-cfg,mmio"); > + qemu_fdt_setprop_sized_cells(vbi->fdt, nodename, "reg", > + 2, base, 2, FW_CFG_SIZE, > + 2, base + FW_CFG_SIZE, 2, FW_CFG_DATA_SIZE);
Overkill suggestion alert, but how about defining something like #define FW_CFG_SIZE_ALIGNED \ MIN(QEMU_ALIGN_UP(FW_CFG_SIZE, FW_CFG_DATA_SIZE), \ QEMU_ALIGN_UP(FW_CFG_SIZE, 4)) and then using that in your memmap size calculation and fw-cfg-data base address calculation. The only reason I suggest this is because it's hard to tell that fw-cfg-data's address will be naturally aligned without hunting down the definition of FW_CFG_DATA_SIZE. And, if it were to change (which it probably never will), then it may not be. > + g_free(nodename); > +} > + > static void *machvirt_dtb(const struct arm_boot_info *binfo, int *fdt_size) > { > const VirtBoardInfo *board = (const VirtBoardInfo *)binfo; > @@ -604,6 +623,8 @@ static void machvirt_init(MachineState *machine) > */ > create_virtio_devices(vbi, pic); > > + create_fw_cfg(vbi); > + > vbi->bootinfo.ram_size = machine->ram_size; > vbi->bootinfo.kernel_filename = machine->kernel_filename; > vbi->bootinfo.kernel_cmdline = machine->kernel_cmdline; > -- > 1.8.3.1 >