KVM: selftests: Add "-c" parameter to dirty log test

It's only used to override the existing dirty ring size/count.  If
with a bigger ring count, we test async of dirty ring.  If with a
smaller ring count, we test ring full code path.  Async is default.

It has no use for non-dirty-ring tests.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20201001012241.6208-1-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
index 85c5d07..b1f8731 100644 (file)
--- a/tools/testing/selftests/kvm/dirty_log_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -183,6 +183,7 @@ static enum log_mode_t host_log_mode_option = LOG_MODE_ALL;
 /* Logging mode for current run */
 static enum log_mode_t host_log_mode;
 static pthread_t vcpu_thread;
+static uint32_t test_dirty_ring_count = TEST_DIRTY_RING_COUNT;
 
 static void vcpu_kick(void)
 {
@@ -257,7 +258,7 @@ static void dirty_ring_create_vm_done(struct kvm_vm *vm)
         * Switch to dirty ring mode after VM creation but before any
         * of the vcpu creation.
         */
-       vm_enable_dirty_ring(vm, TEST_DIRTY_RING_COUNT *
+       vm_enable_dirty_ring(vm, test_dirty_ring_count *
                             sizeof(struct kvm_dirty_gfn));
 }
 
@@ -279,7 +280,7 @@ static uint32_t dirty_ring_collect_one(struct kvm_dirty_gfn *dirty_gfns,
        uint32_t count = 0;
 
        while (true) {
-               cur = &dirty_gfns[*fetch_index % TEST_DIRTY_RING_COUNT];
+               cur = &dirty_gfns[*fetch_index % test_dirty_ring_count];
                if (!dirty_gfn_is_dirtied(cur))
                        break;
                TEST_ASSERT(cur->slot == slot, "Slot number didn't match: "
@@ -803,6 +804,9 @@ static void help(char *name)
        printf("usage: %s [-h] [-i iterations] [-I interval] "
               "[-p offset] [-m mode]\n", name);
        puts("");
+       printf(" -c: specify dirty ring size, in number of entries\n");
+       printf("     (only useful for dirty-ring test; default: %"PRIu32")\n",
+              TEST_DIRTY_RING_COUNT);
        printf(" -i: specify iteration counts (default: %"PRIu64")\n",
               TEST_HOST_LOOP_N);
        printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
@@ -858,8 +862,11 @@ int main(int argc, char *argv[])
        guest_mode_init(VM_MODE_P40V48_4K, true, true);
 #endif
 
-       while ((opt = getopt(argc, argv, "hi:I:p:m:M:")) != -1) {
+       while ((opt = getopt(argc, argv, "c:hi:I:p:m:M:")) != -1) {
                switch (opt) {
+               case 'c':
+                       test_dirty_ring_count = strtol(optarg, NULL, 10);
+                       break;
                case 'i':
                        iterations = strtol(optarg, NULL, 10);
                        break;