Re: [PATCH] aspeed: Introduce helper for 32-bit hosts limitation

[Alex Bennée]

Cédric Le Goater <clg@kaod.org> writes:

> On 32-bit hosts, RAM has a 2047 MB limit. Use a macro to define the
> default ram size of machines (AST2600 SoC) that can have 2 GB.
>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  hw/arm/aspeed.c | 21 +++++++++------------
>  1 file changed, 9 insertions(+), 12 deletions(-)
>
> diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c
> index 6880998484cd..9fca644d920e 100644
> --- a/hw/arm/aspeed.c
> +++ b/hw/arm/aspeed.c
> @@ -47,6 +47,13 @@ struct AspeedMachineState {
>      char *spi_model;
>  };
>  
> +/* On 32-bit hosts, lower RAM to 1G because of the 2047 MB limit */
> +#if HOST_LONG_BITS == 32
> +#define ASPEED_RAM_SIZE(sz) MIN((sz), 1 * GiB)
> +#else
> +#define ASPEED_RAM_SIZE(sz) (sz)
> +#endif
> +

On the one hand this seems a bit hacky to change the guest definition
based on the host architecture - to revive an ongoing argument about
64-on-32 configurations this seems an even more obvious subset of the
problem because regardless of the hoop jumping we do in code generation
we are limited in how much ram we can allocate.

On the other hand at least this moves the hackiness to one place:

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro