KVM: selftests: Add missing close and munmap in __vm_mem_region_delete()

Deleting a memslot (when freeing a VM) is not closing the backing fd,
nor it's unmapping the alias mapping. Fix by adding the missing close
and munmap.
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Reviewed-by: Oliver Upton <oupton@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221017195834.2295901-4-ricarkol@google.com

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -586,6 +586,12 @@ static void __vm_mem_region_delete(struct kvm_vm *vm,
 	sparsebit_free(&region->unused_phy_pages);
 	ret = munmap(region->mmap_start, region->mmap_size);
 	TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
+	if (region->fd >= 0) {
+		/* There's an extra map when using shared memory. */
+		ret = munmap(region->mmap_alias, region->mmap_size);
+		TEST_ASSERT(!ret, __KVM_SYSCALL_ERROR("munmap()", ret));
+		close(region->fd);
+	}
 
 	free(region);
 }