KVM: selftests: Assign guest page size in sync area early in memslot_…

…perf_test

The guest page size in the synchronization area is needed by all test
cases. So it's reasonable to set it in the unified preparation function
(prepare_vm()).

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/r/20230118092133.320003-3-gshan@redhat.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

tools/testing/selftests/kvm/memslot_perf_test.c

@@ -347,6 +347,7 @@ static bool prepare_vm(struct vm_data *data, int nslots, uint64_t *maxslots,
 	virt_map(data->vm, MEM_GPA, MEM_GPA, data->npages);
 
 	sync = (typeof(sync))vm_gpa2hva(data, MEM_SYNC_GPA, NULL);
+	sync->guest_page_size = data->vm->page_size;
 	atomic_init(&sync->start_flag, false);
 	atomic_init(&sync->exit_flag, false);
 	atomic_init(&sync->sync_flag, false);
@@ -808,8 +809,6 @@ static bool test_execute(int nslots, uint64_t *maxslots,
 	}
 
 	sync = (typeof(sync))vm_gpa2hva(data, MEM_SYNC_GPA, NULL);
-
-	sync->guest_page_size = data->vm->page_size;
 	if (tdata->prepare &&
 	    !tdata->prepare(data, sync, maxslots)) {
 		ret = false;