From 20bccb82ff3ea09bcb7c4ee226d3160cab15f7da Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 24 Oct 2016 16:26:49 +0100 Subject: cpu: Support a target CPU having a variable page size Support target CPUs having a page size which isn't knownn at compile time. To use this, the CPU implementation should: * define TARGET_PAGE_BITS_VARY * not define TARGET_PAGE_BITS * define TARGET_PAGE_BITS_MIN to the smallest value it might possibly want for TARGET_PAGE_BITS * call set_preferred_target_page_bits() in its realize function to indicate the actual preferred target page size for the CPU (and report any error from it) In CONFIG_USER_ONLY, the CPU implementation should continue to define TARGET_PAGE_BITS appropriately for the guest OS page size. Machines which want to take advantage of having the page size something larger than TARGET_PAGE_BITS_MIN must set the MachineClass minimum_page_bits field to a value which they guarantee will be no greater than the preferred page size for any CPU they create. Note that changing the target page size by setting minimum_page_bits is a migration compatibility break for that machine. For debugging purposes, attempts to use TARGET_PAGE_SIZE before it has been finally confirmed will assert. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson --- include/exec/cpu-all.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/exec/cpu-all.h') diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h index b6a705982f..861260d3db 100644 --- a/include/exec/cpu-all.h +++ b/include/exec/cpu-all.h @@ -189,6 +189,15 @@ void address_space_stq(AddressSpace *as, hwaddr addr, uint64_t val, /* page related stuff */ +#ifdef TARGET_PAGE_BITS_VARY +extern bool target_page_bits_decided; +extern int target_page_bits; +#define TARGET_PAGE_BITS ({ assert(target_page_bits_decided); \ + target_page_bits; }) +#else +#define TARGET_PAGE_BITS_MIN TARGET_PAGE_BITS +#endif + #define TARGET_PAGE_SIZE (1 << TARGET_PAGE_BITS) #define TARGET_PAGE_MASK ~(TARGET_PAGE_SIZE - 1) #define TARGET_PAGE_ALIGN(addr) (((addr) + TARGET_PAGE_SIZE - 1) & TARGET_PAGE_MASK) -- cgit 1.4.1