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). I did think about also adding a "default_ram" field so each board could default to the same amount of RAM that real hardware has, but since we allocate RAM up front rather than only when accessed, this would push the initial default allocated RAM size up from 128MB to 1GB on models like the PBX A9, and it didn't seem very friendly to do that. I'm happy to be persuaded back again, though :-) This patchset was prompted by bugs like: https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/584480 https://bugs.launchpad.net/ubuntu/+source/rootstock/+bug/570588 Peter Maydell (2): Allow boards to specify maximum RAM size hw: Add maximum RAM specifications for ARM devboard models hw/boards.h | 1 + hw/integratorcp.c | 1 + hw/realview.c | 11 +++++++++++ hw/versatilepb.c | 5 +++++ vl.c | 16 +++++++++++++++- 5 files changed, 33 insertions(+), 1 deletions(-)