diff options
Diffstat (limited to 'arch/x86/xen/setup.c')
| -rw-r--r-- | arch/x86/xen/setup.c | 112 |
1 files changed, 109 insertions, 3 deletions
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 9729c903404b..105db2501050 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -18,8 +18,10 @@ #include <asm/xen/hypervisor.h> #include <asm/xen/hypercall.h> +#include <xen/xen.h> #include <xen/page.h> #include <xen/interface/callback.h> +#include <xen/interface/memory.h> #include <xen/interface/physdev.h> #include <xen/interface/memory.h> #include <xen/features.h> @@ -34,6 +36,39 @@ extern void xen_sysenter_target(void); extern void xen_syscall_target(void); extern void xen_syscall32_target(void); +/* Amount of extra memory space we add to the e820 ranges */ +phys_addr_t xen_extra_mem_start, xen_extra_mem_size; + +/* + * The maximum amount of extra memory compared to the base size. The + * main scaling factor is the size of struct page. At extreme ratios + * of base:extra, all the base memory can be filled with page + * structures for the extra memory, leaving no space for anything + * else. + * + * 10x seems like a reasonable balance between scaling flexibility and + * leaving a practically usable system. + */ +#define EXTRA_MEM_RATIO (10) + +static __init void xen_add_extra_mem(unsigned long pages) +{ + u64 size = (u64)pages * PAGE_SIZE; + u64 extra_start = xen_extra_mem_start + xen_extra_mem_size; + + if (!pages) + return; + + e820_add_region(extra_start, size, E820_RAM); + sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); + + memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA"); + + xen_extra_mem_size += size; + + xen_max_p2m_pfn = PFN_DOWN(extra_start + size); +} + static unsigned long __init xen_release_chunk(phys_addr_t start_addr, phys_addr_t end_addr) { @@ -105,16 +140,65 @@ static unsigned long __init xen_return_unused_memory(unsigned long max_pfn, /** * machine_specific_memory_setup - Hook for machine specific memory setup. **/ - char * __init xen_memory_setup(void) { + static struct e820entry map[E820MAX] __initdata; + unsigned long max_pfn = xen_start_info->nr_pages; + unsigned long long mem_end; + int rc; + struct xen_memory_map memmap; + unsigned long extra_pages = 0; + unsigned long extra_limit; + int i; + int op; max_pfn = min(MAX_DOMAIN_PAGES, max_pfn); + mem_end = PFN_PHYS(max_pfn); + + memmap.nr_entries = E820MAX; + set_xen_guest_handle(memmap.buffer, map); + + op = xen_initial_domain() ? + XENMEM_machine_memory_map : + XENMEM_memory_map; + rc = HYPERVISOR_memory_op(op, &memmap); + if (rc == -ENOSYS) { + memmap.nr_entries = 1; + map[0].addr = 0ULL; + map[0].size = mem_end; + /* 8MB slack (to balance backend allocations). */ + map[0].size += 8ULL << 20; + map[0].type = E820_RAM; + rc = 0; + } + BUG_ON(rc); e820.nr_map = 0; + xen_extra_mem_start = mem_end; + for (i = 0; i < memmap.nr_entries; i++) { + unsigned long long end = map[i].addr + map[i].size; + + if (map[i].type == E820_RAM) { + if (map[i].addr < mem_end && end > mem_end) { + /* Truncate region to max_mem. */ + u64 delta = end - mem_end; + + map[i].size -= delta; + extra_pages += PFN_DOWN(delta); + + end = mem_end; + } + } - e820_add_region(0, PFN_PHYS((u64)max_pfn), E820_RAM); + if (end > xen_extra_mem_start) + xen_extra_mem_start = end; + + /* If region is non-RAM or below mem_end, add what remains */ + if ((map[i].type != E820_RAM || map[i].addr < mem_end) && + map[i].size > 0) + e820_add_region(map[i].addr, map[i].size, map[i].type); + } /* * Even though this is normal, usable memory under Xen, reserve @@ -136,7 +220,29 @@ char * __init xen_memory_setup(void) sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); - xen_return_unused_memory(xen_start_info->nr_pages, &e820); + extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820); + + /* + * Clamp the amount of extra memory to a EXTRA_MEM_RATIO + * factor the base size. On non-highmem systems, the base + * size is the full initial memory allocation; on highmem it + * is limited to the max size of lowmem, so that it doesn't + * get completely filled. + * + * In principle there could be a problem in lowmem systems if + * the initial memory is also very large with respect to + * lowmem, but we won't try to deal with that here. + */ + extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)), + max_pfn + extra_pages); + + if (extra_limit >= max_pfn) + extra_pages = extra_limit - max_pfn; + else + extra_pages = 0; + + if (!xen_initial_domain()) + xen_add_extra_mem(extra_pages); return "Xen"; } |