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Re: [Qemu-devel] [qemu PATCH 2/2] arm: add fw_cfg to "virt" board
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [qemu PATCH 2/2] arm: add fw_cfg to "virt" board |
Date: |
Fri, 28 Nov 2014 11:43:32 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 |
On 11/28/14 11:38, Andrew Jones wrote:
> 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 <address@hidden>
>> ---
>> 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("/address@hidden" 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.
Why does it need to be aligned?
The selector register is aligned at a 64KB boundary (for independent,
strict reasons).
The data register is not aligned at all, and -- AFAICS -- it need not
be, because it's 1 byte wide. (In fact the ARM-specific
Mmio(Read|Write)XX functions in edk2 enforce natural alignment, and the
above layout passes without problems.)
The full register block is 3 bytes wide. Is that a problem?
Thanks
Laszlo
>
>> + 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
>>
[Qemu-devel] [edk2 PATCH 00/12] consume fw_cfg boot order in ArmVirtualizationQemu, Laszlo Ersek, 2014/11/27
- [Qemu-devel] [edk2 PATCH 01/12] ArmVirtualizationPkg: VirtFdtDxe: forward FwCfg addresses from DTB to PCDs, Laszlo Ersek, 2014/11/27
- [Qemu-devel] [edk2 PATCH 02/12] ArmVirtualizationPkg: introduce QemuFwCfgLib instance for DXE drivers, Laszlo Ersek, 2014/11/27
- [Qemu-devel] [edk2 PATCH 03/12] ArmVirtualizationPkg: clone PlatformIntelBdsLib from ArmPlatformPkg, Laszlo Ersek, 2014/11/27
- [Qemu-devel] [edk2 PATCH 04/12] ArmVirtualizationPkg: PlatformIntelBdsLib: add basic policy, Laszlo Ersek, 2014/11/27
- [Qemu-devel] [edk2 PATCH 05/12] OvmfPkg: extract QemuBootOrderLib, Laszlo Ersek, 2014/11/27
- [Qemu-devel] [edk2 PATCH 07/12] OvmfPkg: introduce VIRTIO_MMIO_TRANSPORT_GUID, Laszlo Ersek, 2014/11/27