diff options
| -rw-r--r-- | arch/x86/xen/setup.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index b1dbdaa23ecc..769c4b01fa32 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -118,16 +118,18 @@ static unsigned long __init xen_return_unused_memory(unsigned long max_pfn, const struct e820map *e820) { phys_addr_t max_addr = PFN_PHYS(max_pfn); - phys_addr_t last_end = 0; + phys_addr_t last_end = ISA_END_ADDRESS; unsigned long released = 0; int i; + /* Free any unused memory above the low 1Mbyte. */ for (i = 0; i < e820->nr_map && last_end < max_addr; i++) { phys_addr_t end = e820->map[i].addr; end = min(max_addr, end); - released += xen_release_chunk(last_end, end); - last_end = e820->map[i].addr + e820->map[i].size; + if (last_end < end) + released += xen_release_chunk(last_end, end); + last_end = max(last_end, e820->map[i].addr + e820->map[i].size); } if (last_end < max_addr) @@ -164,6 +166,7 @@ char * __init xen_memory_setup(void) XENMEM_memory_map; rc = HYPERVISOR_memory_op(op, &memmap); if (rc == -ENOSYS) { + BUG_ON(xen_initial_domain()); memmap.nr_entries = 1; map[0].addr = 0ULL; map[0].size = mem_end; @@ -201,12 +204,13 @@ char * __init xen_memory_setup(void) } /* - * Even though this is normal, usable memory under Xen, reserve - * ISA memory anyway because too many things think they can poke + * In domU, the ISA region is normal, usable memory, but we + * reserve ISA memory anyway because too many things poke * about in there. * - * In a dom0 kernel, this region is identity mapped with the - * hardware ISA area, so it really is out of bounds. + * In Dom0, the host E820 information can leave gaps in the + * ISA range, which would cause us to release those pages. To + * avoid this, we unconditionally reserve them here. */ e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, E820_RESERVED); |