From 35ae11fd146384d222f3bb1f17eed1970cc92c36 Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Fri, 6 Feb 2009 19:09:48 -0800 Subject: xen: Use host-provided E820 map Rather than simply using a flat memory map from Xen, use its provided E820 map. This allows the domain builder to tell the domain to reserve space for more pages than those initially provided at domain-build time. It also allows the host to specify holes in the address space (for PCI-passthrough, for example). Signed-off-by: Ian Campbell Signed-off-by: Jeremy Fitzhardinge --- arch/x86/xen/setup.c | 38 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 328b003..dd2eb2a 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -19,6 +19,7 @@ #include #include +#include #include #include #include @@ -107,13 +108,46 @@ static unsigned long __init xen_return_unused_memory(unsigned long max_pfn, 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; + int i; 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); + + rc = HYPERVISOR_memory_op(XENMEM_memory_map, &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; - - e820_add_region(0, PFN_PHYS((u64)max_pfn), E820_RAM); + 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) + continue; + if (end > mem_end) { + /* Truncate region to max_mem. */ + map[i].size -= end - mem_end; + } + } + if (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 -- cgit v1.1