s390/kvm: split kvm mem slots at 4TB

/*

 * KVM does only support memory slots up to KVM_MEM_MAX_NR_PAGES pages

 * as the dirty bitmap must be managed by bitops that take an int as

 * position indicator. If we have a guest beyond that we will split off

 * new subregions. The split must happen on a segment boundary (1MB).

 * position indicator. This would end at an unaligned  address

 * (0x7fffff00000). As future variants might provide larger pages

 * and to make all addresses properly aligned, let us split at 4TB.

 */

#define KVM_MEM_MAX_NR_PAGES ((1ULL << 31) - 1)

#define SEG_MSK (~0xfffffULL)

#define KVM_SLOT_MAX_BYTES ((KVM_MEM_MAX_NR_PAGES * TARGET_PAGE_SIZE) & SEG_MSK)

#define KVM_SLOT_MAX_BYTES (4UL * TiB)

static CPUWatchpoint hw_watchpoint;

/*