Re: [Qemu-devel] [PATCH v2] vexpress: Add support for the -bios flag to provide firmware

[Peter Crosthwaite]

On Thu, May 29, 2014 at 10:24 PM, Peter Maydell
<address@hidden> wrote:
> From: Grant Likely <address@hidden>
>
> Right now to run firmware inside the QEMU VExpress model requires
> padding out the firmware image to the size of the virtual flash and
> passing it in via the -pflash argument. If the firmware image is passed
> without padding, then QEMU will fail. Also, when passed as a -pflash
> argument, QEMU treats the file as persistent storage and will modify the
> file.
>

A little out of scope, but no support for read-only backing images is
somewhat annoying. Is it feasible to patch the block layer (or perhaps
we need to do something to pflash?) to handle a read-only -pflash file
as init-only data (and then use the normal volatile ram-based storage
once the file is loaded)?

Then the semantics of "don't change my ROM file even if the real
hardware can do it in real life" can just be handled with file perms.

> The -bios flag provides the semantics that we want for providing a
> firmware image. This patch maps the contents of the -bios file into the
> address space at the boot flash location.
>
> Tested with the vexpress-a15 model and the Tianocore port.
>
> Signed-off-by: Grant Likely <address@hidden>
> Tested-by: Roy Franz <address@hidden>
> [PMM: folded long line, removed stray \n from error message,
>  use correct variable for printing image name, exit(1) rather than 0]
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> Grant submitted v1 of this a few months back; it was pretty nearly
> correct, so I've just tidied up the loose ends so we can get it into
> QEMU 2.1. Tested by booting the UEFI blob from
> https://wiki.linaro.org/LEG/Engineering/Kernel/UEFI/VersatileExpress/QEMU
>
>  hw/arm/vexpress.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
>
> diff --git a/hw/arm/vexpress.c b/hw/arm/vexpress.c
> index 33ff422..0f8f175 100644
> --- a/hw/arm/vexpress.c
> +++ b/hw/arm/vexpress.c
> @@ -28,6 +28,7 @@
>  #include "net/net.h"
>  #include "sysemu/sysemu.h"
>  #include "hw/boards.h"
> +#include "hw/loader.h"
>  #include "exec/address-spaces.h"
>  #include "sysemu/blockdev.h"
>  #include "hw/block/flash.h"
> @@ -528,6 +529,18 @@ static void vexpress_common_init(VEDBoardInfo 
> *daughterboard,
>      daughterboard->init(daughterboard, machine->ram_size, machine->cpu_model,
>                          pic);
>
> +    /*
> +     * If a bios file was provided, attempt to map it into memory
> +     */
> +    if (bios_name) {
> +        const char *fn = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
> +        if (!fn || load_image_targphys(fn, map[VE_NORFLASH0],
> +                                       VEXPRESS_FLASH_SIZE) < 0) {
> +            error_report("Could not load rom image '%s'", bios_name);

"ROM"

Otherwise

Reviewed-by: Peter Crosthwaite <address@hidden>

Regards,
Peter

> +            exit(1);
> +        }
> +    }
> +
>      /* Motherboard peripherals: the wiring is the same but the
>       * addresses vary between the legacy and A-Series memory maps.
>       */
> --
> 1.9.2
>
>