[Qemu-devel] Re: [PATCH v2 0/5] Let boards state maximum RAM limits in QEMUMachine struct

[Blue Swirl]

On Mon, Mar 28, 2011 at 4:44 PM, Peter Maydell <address@hidden> wrote:
> This fairly simple patchset adds a new 'max_ram' field to the QEMUMachine
> structure so that a board model can specify the maximum RAM it will accept.
> We can then produce a friendly diagnostic message when the user tries to
> start qemu with a '-m' option asking for more RAM than that. (Currently
> most of the ARM devboard models respond with an obscure guest crash when
> the guest tries to access RAM and finds device registers instead.)
>
> If no maximum size is specified we default to the old behaviour of
> "do not impose any limit".
>
> The advantage of doing this in vl.c rather than in each board (apart
> from avoiding code duplication) is that we can distinguish between
> "the user asked for more RAM than we support" (an error) and "the global
> default RAM size is more than our maximum" (just cap the RAM size to
> the board maximum).
>
> Changes in v2:
>  * use target_physaddr_t rather than ram_addr_t for max_ram, so
>   we can specify maximum ram sizes for 64 bit target boards
>  * new patches 3,4 which update sun4m to use the generic max_ram, so
>   we can delete the sun4m-specific code which was doing the same job
>  * patch 5 does some tidy-up of sun4m init functions; not strictly
>   related but the assert() at least is enabled by the cleanup done
>   in patch 3.
>
> The number of changed lines in sun4m.c is a bit alarming but it's
> almost all just moving code around...

Very nice patch set!