From d61a12cb9af5b355a38e0c0106e91224b49195ce Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 13 Dec 2022 00:16:42 +0000 Subject: [PATCH] KVM: selftests: Fix divide-by-zero bug in memslot_perf_test MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Check that the number of pages per slot is non-zero in get_max_slots() prior to computing the remaining number of pages. clang generates code that uses an actual DIV for calculating the remaining, which causes a #DE if the total number of pages is less than the number of slots. traps: memslot_perf_te[97611] trap divide error ip:4030c4 sp:7ffd18ae58f0 error:0 in memslot_perf_test[401000+cb000] Fixes: a69170c65acd ("KVM: selftests: memslot_perf_test: Report optimal memory slots") Signed-off-by: Sean Christopherson Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20221213001653.3852042-4-seanjc@google.com> Signed-off-by: Paolo Bonzini --- tools/testing/selftests/kvm/memslot_perf_test.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/kvm/memslot_perf_test.c b/tools/testing/selftests/kvm/memslot_perf_test.c index e698306..e6587e1 100644 --- a/tools/testing/selftests/kvm/memslot_perf_test.c +++ b/tools/testing/selftests/kvm/memslot_perf_test.c @@ -265,6 +265,9 @@ static uint64_t get_max_slots(struct vm_data *data, uint32_t host_page_size) slots = data->nslots; while (--slots > 1) { pages_per_slot = mempages / slots; + if (!pages_per_slot) + continue; + rempages = mempages % pages_per_slot; if (check_slot_pages(host_page_size, guest_page_size, pages_per_slot, rempages)) -- 2.7.4