Commit 578f3c7b authored by Laszlo Ersek's avatar Laszlo Ersek Committed by Peter Maydell
Browse files

arm: add fw_cfg to "virt" board 



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.

Because MMIO access is slow on ARM KVM, we enable the guest, with
fw_cfg_init_mem_wide(), to transfer up to 8 bytes with a single access.
This has been measured to speed up transfers up to 7.5-fold, relative to
single byte data access, on both ARM KVM and x86_64 TCG.

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. The DTB properties follow the documentation in
the Linux source file "Documentation/devicetree/bindings/arm/fw-cfg.txt".

fw_cfg automatically exports a number of files to the guest; for example,
"bootorder" (see fw_cfg_machine_reset()).

Signed-off-by: default avatarLaszlo Ersek <lersek@redhat.com>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 1419250305-31062-9-git-send-email-pbonzini@redhat.com
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent 6c87e3d5

hw/arm/virt.c

+21 −0
Original line number Diff line number Diff line
@@ -68,6 +68,7 @@ enum { 
    VIRT_UART,

    VIRT_MMIO,

    VIRT_RTC,

    VIRT_FW_CFG,

};



typedef struct MemMapEntry {
@@ -125,6 +126,7 @@ static const MemMapEntry a15memmap[] = { 
    [VIRT_GIC_CPU] =    { 0x08010000, 0x00010000 },

    [VIRT_UART] =       { 0x09000000, 0x00001000 },

    [VIRT_RTC] =        { 0x09010000, 0x00001000 },

    [VIRT_FW_CFG] =     { 0x09020000, 0x0000000a },

    [VIRT_MMIO] =       { 0x0a000000, 0x00000200 },

    /* ...repeating for a total of NUM_VIRTIO_TRANSPORTS, each of that size */

    /* 0x10000000 .. 0x40000000 reserved for PCI */
@@ -537,6 +539,23 @@ 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;

    hwaddr size = vbi->memmap[VIRT_FW_CFG].size;

    char *nodename;



    fw_cfg_init_mem_wide(base + 8, base, 8);



    nodename = g_strdup_printf("/fw-cfg@%" PRIx64, base);

    qemu_fdt_add_subnode(vbi->fdt, nodename);

    qemu_fdt_setprop_string(vbi->fdt, nodename,

                            "compatible", "qemu,fw-cfg-mmio");

    qemu_fdt_setprop_sized_cells(vbi->fdt, nodename, "reg",

                                 2, base, 2, size);

    g_free(nodename);

}



static void *machvirt_dtb(const struct arm_boot_info *binfo, int *fdt_size)

{

    const VirtBoardInfo *board = (const VirtBoardInfo *)binfo;
@@ -627,6 +646,8 @@ 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;