Remap vmspace0 from the vkernel

vkernel_remap.c

static void
recreate_kva(void)
{
        void *base;
        void *try;

        try = (void *)KvaStart;
        base = try;
        base = mmap(try, KERNEL_KVA_SIZE, PROT_READ|PROT_WRITE,
                        MAP_FILE|MAP_SHARED|MAP_VPAGETABLE,
                        MemImageFd, 0);
        if (base != try) {
                err(1, "Unable to mmap() kernel virtual memory!");
                /* NOT REACHED */
        }
        madvise(base, KERNEL_KVA_SIZE, MADV_NOSYNC);

        printf("XXX KVM mapped at %p-%p\n", (void *)KvaStart, (void *)KvaEnd);
        mcontrol(base, KERNEL_KVA_SIZE, MADV_SETMAP,
                        0 | VPTE_R | VPTE_W | VPTE_V);
}