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arm: add fw_cfg to "virt" board

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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: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1419250305-31062-9-git-send-email-pbonzini@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Laszlo Ersek 2014-12-22 13:11:42 +01:00 committed by Peter Maydell
parent 6c87e3d596
commit 578f3c7b08
1 changed files with 21 additions and 0 deletions
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21
hw/arm/virt.c
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@ -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;