Re: [PATCH v2 04/30] hw/arm/raspi: Extract the RAM size from the board revision

[BALATON Zoltan]

On Thu, 6 Feb 2020, Philippe Mathieu-Daudé wrote:
> The board revision encode the amount of RAM. Add a helper
> to extract the RAM size, and use it.
> Since the amount of RAM is fixed (it is impossible to physically
> modify to have more or less RAM), do not allow sizes different
> than the one anounced by the manufacturer.
>
> Acked-by: Igor Mammedov <address@hidden>
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> ---
> Cc: Alistair Francis <address@hidden>
>
> hw/arm/raspi.c | 15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/hw/arm/raspi.c b/hw/arm/raspi.c
> index 13d41dfce6..2f5cd32c5e 100644
> --- a/hw/arm/raspi.c
> +++ b/hw/arm/raspi.c
> @@ -13,6 +13,7 @@
>
> #include "qemu/osdep.h"
> #include "qemu/units.h"
> +#include "qemu/cutils.h"
> #include "qapi/error.h"
> #include "cpu.h"
> #include "hw/arm/bcm2836.h"
> @@ -48,6 +49,12 @@ FIELD(REV_CODE, MANUFACTURER,      16, 4);
> FIELD(REV_CODE, MEMORY_SIZE,       20, 3);
> FIELD(REV_CODE, STYLE,             23, 1);
>
> +static uint64_t board_ram_size(uint32_t board_rev)
> +{
> +    assert(FIELD_EX32(board_rev, REV_CODE, STYLE)); /* Only new style */
> +    return 256 * MiB << FIELD_EX32(board_rev, REV_CODE, MEMORY_SIZE);
> +}
> +
> static int board_processor_id(uint32_t board_rev)
> {
>     assert(FIELD_EX32(board_rev, REV_CODE, STYLE)); /* Only new style */
> @@ -190,15 +197,17 @@ static void raspi_init(MachineState *machine, uint32_t 
> board_rev)
> {
>     RasPiState *s = g_new0(RasPiState, 1);
>     int version = board_version(board_rev);
> +    uint64_t ram_size = board_ram_size(board_rev);
>     uint32_t vcram_size;
>     DriveInfo *di;
>     BlockBackend *blk;
>     BusState *bus;
>     DeviceState *carddev;
>
> -    if (machine->ram_size > 1 * GiB) {
> -        error_report("Requested ram size is too large for this machine: "
> -                     "maximum is 1GB");
> +    if (machine->ram_size != ram_size) {
> +        char *size_str = size_to_str(ram_size);
> +        error_report("This machine can only be used with %s", size_str);

Reword error message so it says it has problem with memory as this is not 
clear from the above and user getting it after a command line does not 
have context to tell what the printed number means.

Regards,
BALATON Zoltan


> +        g_free(size_str);
>         exit(1);
>     }