diff options
Diffstat (limited to 'i386/i386at')
| -rw-r--r-- | i386/i386at/model_dep.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/i386/i386at/model_dep.c b/i386/i386at/model_dep.c index 4e7093c..f6e797c 100644 --- a/i386/i386at/model_dep.c +++ b/i386/i386at/model_dep.c @@ -261,6 +261,8 @@ void db_reset_cpu(void) void mem_size_init(void) { + vm_offset_t max_phys_size; + /* Physical memory on all PCs starts at physical address 0. XX make it a constant. */ phys_first_addr = 0; @@ -285,12 +287,13 @@ mem_size_init(void) printf("AT386 boot: physical memory from 0x%x to 0x%x\n", phys_first_addr, phys_last_addr); - /* Reserve 1/6 of the memory address space for virtual mappings. + /* Reserve room for virtual mappings. * Yes, this loses memory. Blame i386. */ - if (phys_last_addr > ((VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 6) * 5) { - phys_last_addr = ((VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / 6) * 5; + max_phys_size = VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS - VM_KERNEL_MAP_SIZE; + if (phys_last_addr - phys_first_addr > max_phys_size) { + phys_last_addr = phys_first_addr + max_phys_size; printf("Truncating memory size to %dMiB\n", (phys_last_addr - phys_first_addr) / (1024 * 1024)); - /* TODO Xen: free lost memory */ + /* TODO Xen: be nice, free lost memory */ } phys_first_addr = round_page(phys_first_addr); |