This set of patches is a development based on the ones from Vijaya: the general idea is similar but I have tried to improve the interface for defining the page size a bit. I've also tweaked patches 2 and 3 to address code review comments.
The basic idea here is that: * the target CPU implementation has to opt into variable page size by defining TARGET_PAGE_BITS_VARY, and then calling set_preferred_target_page_bits() in its realize function with whatever the CPU as instantiated actually requires * the machine also has to opt in, by specifying a new MachineClass field which states the value they guarantee will be no greater than the preferred page size for any CPU they create * we finalize the decision about page size in cpu_exec_init_all() (and then later attempts to create CPUs which can't cope with that decision are failed) I would ideally have liked to finalize things much later, but this is in practice hugely difficult because so many things (in particular all the address space/memory system code) assume the target page size is known. Note that setting minimum_page-bits for a machine is a migration compatibility break (the RAM migration format assumes both sides have the same idea of a page size). Mismatches will probably result in an unhelpfully obscure migration failure. (Possibly we could have the migration send the page size if it was different from TARGET_PAGE_BITS_MIN so we at least got a nice error?) This could in theory be extended to the user-mode binaries, but for the moment I have just required them to define a fixed TARGET_PAGE_BITS. NB: I have only very lightly tested these and haven't attempted to measure performance at all. There is an assert() in the definition of TARGET_PAGE_BITS which is good for making sure it isn't used before it's valid but not so good for speed. thanks -- PMM Peter Maydell (3): cpu: Support a target CPU having a variable page size target-arm: Make page size a runtime setting hw/arm/virt: Set minimum_page_bits to 12 Vijaya Kumar K (3): migration: Remove static allocation of xzblre cache buffer exec.c: Remove static allocation of sub_section of sub_page translate-all.c: Compute L1 page table properties at runtime exec.c | 47 ++++++++++++++++++++++++++++++++--- hw/arm/virt.c | 2 ++ include/exec/cpu-all.h | 8 ++++++ include/hw/boards.h | 7 ++++++ include/qemu-common.h | 13 ++++++++++ migration/ram.c | 4 ++- target-arm/cpu.c | 24 ++++++++++++++++++ target-arm/cpu.h | 9 ++++--- translate-all.c | 67 +++++++++++++++++++++++++++++++++----------------- vl.c | 10 ++++++++ 10 files changed, 160 insertions(+), 31 deletions(-) -- 1.9.1
