@@ -2435,6 +2435,55 @@ static int find_kvm_machine_type(MachineState *ms)
return type;
}
+static int kvm_setup_dirty_ring(KVMState *s)
+{
+ uint64_t dirty_log_manual_caps;
+ int ret;
+
+ /*
+ * Enable KVM dirty ring if supported, otherwise fall back to
+ * dirty logging mode
+ */
+ ret = kvm_dirty_ring_init(s);
+ if (ret < 0) {
+ return ret;
+ }
+
+ /*
+ * KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is not needed when dirty ring is
+ * enabled. More importantly, KVM_DIRTY_LOG_INITIALLY_SET will assume no
+ * page is wr-protected initially, which is against how kvm dirty ring is
+ * usage - kvm dirty ring requires all pages are wr-protected at the very
+ * beginning. Enabling this feature for dirty ring causes data corruption.
+ *
+ * TODO: Without KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 and kvm clear dirty log,
+ * we may expect a higher stall time when starting the migration. In the
+ * future we can enable KVM_CLEAR_DIRTY_LOG to work with dirty ring too:
+ * instead of clearing dirty bit, it can be a way to explicitly wr-protect
+ * guest pages.
+ */
+ if (!s->kvm_dirty_ring_size) {
+ dirty_log_manual_caps =
+ kvm_check_extension(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
+ dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
+ KVM_DIRTY_LOG_INITIALLY_SET);
+ s->manual_dirty_log_protect = dirty_log_manual_caps;
+ if (dirty_log_manual_caps) {
+ ret = kvm_vm_enable_cap(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, 0,
+ dirty_log_manual_caps);
+ if (ret) {
+ warn_report("Trying to enable capability %"PRIu64" of "
+ "KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 but failed. "
+ "Falling back to the legacy mode. ",
+ dirty_log_manual_caps);
+ s->manual_dirty_log_protect = 0;
+ }
+ }
+ }
+
+ return 0;
+}
+
static int kvm_init(MachineState *ms)
{
MachineClass *mc = MACHINE_GET_CLASS(ms);
@@ -2454,7 +2503,6 @@ static int kvm_init(MachineState *ms)
const KVMCapabilityInfo *missing_cap;
int ret;
int type;
- uint64_t dirty_log_manual_caps;
qemu_mutex_init(&kml_slots_lock);
@@ -2566,47 +2614,11 @@ static int kvm_init(MachineState *ms)
s->coalesced_pio = s->coalesced_mmio &&
kvm_check_extension(s, KVM_CAP_COALESCED_PIO);
- /*
- * Enable KVM dirty ring if supported, otherwise fall back to
- * dirty logging mode
- */
- ret = kvm_dirty_ring_init(s);
+ ret = kvm_setup_dirty_ring(s);
if (ret < 0) {
goto err;
}
- /*
- * KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is not needed when dirty ring is
- * enabled. More importantly, KVM_DIRTY_LOG_INITIALLY_SET will assume no
- * page is wr-protected initially, which is against how kvm dirty ring is
- * usage - kvm dirty ring requires all pages are wr-protected at the very
- * beginning. Enabling this feature for dirty ring causes data corruption.
- *
- * TODO: Without KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 and kvm clear dirty log,
- * we may expect a higher stall time when starting the migration. In the
- * future we can enable KVM_CLEAR_DIRTY_LOG to work with dirty ring too:
- * instead of clearing dirty bit, it can be a way to explicitly wr-protect
- * guest pages.
- */
- if (!s->kvm_dirty_ring_size) {
- dirty_log_manual_caps =
- kvm_check_extension(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2);
- dirty_log_manual_caps &= (KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE |
- KVM_DIRTY_LOG_INITIALLY_SET);
- s->manual_dirty_log_protect = dirty_log_manual_caps;
- if (dirty_log_manual_caps) {
- ret = kvm_vm_enable_cap(s, KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2, 0,
- dirty_log_manual_caps);
- if (ret) {
- warn_report("Trying to enable capability %"PRIu64" of "
- "KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 but failed. "
- "Falling back to the legacy mode. ",
- dirty_log_manual_caps);
- s->manual_dirty_log_protect = 0;
- }
- }
- }
-
#ifdef KVM_CAP_VCPU_EVENTS
s->vcpu_events = kvm_check_extension(s, KVM_CAP_VCPU_EVENTS);
#endif