Re: [PATCH-for-11.0 v6 05/13] hw/nvram/fw_cfg: Propagate I/O MemoryRegion to fw_cfg_init_io_dma()

[Zhao Liu <zhao1.liu@intel.com>]

On Wed, Dec 03, 2025 at 07:09:33AM +0100, Philippe Mathieu-Daudé wrote:
> Date: Wed,  3 Dec 2025 07:09:33 +0100
> From: Philippe Mathieu-Daudé <philmd@linaro.org>
> Subject: [PATCH-for-11.0 v6 05/13] hw/nvram/fw_cfg: Propagate I/O
>  MemoryRegion to fw_cfg_init_io_dma()
> X-Mailer: git-send-email 2.51.0
> 
> To allow callers to use I/O MemoryRegion different than the
> global get_system_io(), pass it as argument.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  include/hw/nvram/fw_cfg.h | 4 ++--
>  hw/i386/fw_cfg.c          | 3 ++-
>  hw/i386/microvm.c         | 3 ++-
>  hw/i386/pc.c              | 3 ++-
>  hw/nvram/fw_cfg.c         | 5 ++---
>  5 files changed, 10 insertions(+), 8 deletions(-)

...

> diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c
> index 94d22a232ac..69f04d74a15 100644
> --- a/hw/i386/microvm.c
> +++ b/hw/i386/microvm.c
> @@ -289,6 +289,7 @@ static void microvm_memory_init(MicrovmMachineState *mms)
>      X86MachineState *x86ms = X86_MACHINE(mms);
>      MemoryRegion *ram_below_4g, *ram_above_4g;
>      MemoryRegion *system_memory = get_system_memory();
> +    MemoryRegion *io_memory = get_system_io();
>      FWCfgState *fw_cfg;
>      ram_addr_t lowmem = 0xc0000000; /* 3G */
>      int i;
> @@ -319,7 +320,7 @@ static void microvm_memory_init(MicrovmMachineState *mms)
>          e820_add_entry(0x100000000ULL, x86ms->above_4g_mem_size, E820_RAM);
>      }
>  
> -    fw_cfg = fw_cfg_init_io_dma(FW_CFG_IO_BASE, FW_CFG_IO_BASE + 4,
> +    fw_cfg = fw_cfg_init_io_dma(io_memory, FW_CFG_IO_BASE, FW_CFG_IO_BASE + 4,

It seems here we can use get_system_io() directly :).

Otherwise,

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>

>                                  &address_space_memory);
>  
>      fw_cfg_add_i16(fw_cfg, FW_CFG_NB_CPUS, machine->smp.cpus);