Archipelago » qemu

/*

 * Legacy layout for s390:

 * Older S390 KVM requires the topmost vma of the RAM to be

 * smaller than an system defined value, which is at least 256GB.

 * Larger systems have larger values. We put the guest between

 * the end of data segment (system break) and this value. We

 * use 32GB as a base to have enough room for the system break

 * to grow. We also have to use MAP parameters that avoid

 * read-only mapping of guest pages.

 */

static void *legacy_s390_alloc(ram_addr_t size)

{

    void *mem;

    mem = mmap((void *) 0x800000000ULL, size,

               PROT_EXEC|PROT_READ|PROT_WRITE,

               MAP_SHARED | MAP_ANONYMOUS | MAP_FIXED, -1, 0);

    if (mem == MAP_FAILED) {

        fprintf(stderr, "Allocating RAM failed\n");

        abort();

    }

    return mem;

}

void *kvm_arch_vmalloc(ram_addr_t size)

{

    /* Can we use the standard allocation ? */

    if (kvm_check_extension(kvm_state, KVM_CAP_S390_GMAP) &&

        kvm_check_extension(kvm_state, KVM_CAP_S390_COW)) {

        return NULL;

    } else {

        return legacy_s390_alloc(size);

    }

}