cachepc

commit 5975ec7b44887ad54417218251e669cca14bde80
parent 80df08a54cfe9d531e932374cad55cc052a8a73d
Author: Louis Burda <quent.burda@gmail.com>
Date:   Wed, 25 Jan 2023 19:16:45 +0100

Debug copy_to_user occasionally failing in kvm-step

Diffstat:
M
Makefile
 | 
1
+
M
cachepc/event.c
 | 
25
++++++++++++++++++++-----
M
cachepc/event.h
 | 
4
++--
M
cachepc/kvm.c
 | 
26
++------------------------
M
test/kvm-step.c
 | 
6
++++--

5 files changed, 29 insertions(+), 33 deletions(-)
diff --git a/Makefile b/Makefile
@@ -57,6 +57,7 @@ load:
 prep:
 	sudo sh -c "echo 0 > /proc/sys/kernel/watchdog"
 	sudo cpupower frequency-set -d 3.7GHz -u 3.7GHz
+	sudo sh -c "echo 1 > /proc/irq/127/smp_affinity"
 
 util/%: util/%.c $(CACHEPC_UAPI)
 
diff --git a/cachepc/event.c b/cachepc/event.c
@@ -169,7 +169,7 @@ cachepc_event_is_done(uint64_t id)
 }
 
 int
-cachepc_handle_poll_event_ioctl(struct cpc_event __user *event)
+cachepc_poll_event_ioctl(void __user *arg_user)
 {
 	int err;
 
@@ -182,10 +182,19 @@ cachepc_handle_poll_event_ioctl(struct cpc_event __user *event)
 	}
 	read_unlock(&cachepc_event_lock);
 
+	err = 0;
 	write_lock(&cachepc_event_lock);
 	if (cachepc_event_avail) {
-		err = copy_to_user(event, &cachepc_event, sizeof(struct cpc_event));
+		CPC_DBG("Event Poll: Event is avail %px %llu %llu\n", arg_user,
+			cachepc_last_event_sent, cachepc_last_event_acked);
+		err = copy_to_user(arg_user, &cachepc_event, sizeof(cachepc_event));
+		if (err != 0) {
+			CPC_ERR("copy_to_user %i %lu\n", err, sizeof(cachepc_event));
+			err = -EFAULT;
+		}
 	} else {
+		CPC_DBG("Event Poll: Event was avail %llu %llu\n",
+			cachepc_last_event_sent, cachepc_last_event_acked);
 		err = -EAGAIN;
 	}
 	if (!err) cachepc_event_avail = false;
@@ -195,18 +204,24 @@ cachepc_handle_poll_event_ioctl(struct cpc_event __user *event)
 }
 
 int
-cachepc_handle_ack_event_ioctl(uint64_t eventid)
+cachepc_ack_event_ioctl(void __user *arg_user)
 {
+	uint64_t eventid;
 	int err;
 
+	if (!arg_user) return -EINVAL;
+
+	if (copy_from_user(&eventid, arg_user, sizeof(eventid)))
+		return -EFAULT;
+
+	err = 0;
 	write_lock(&cachepc_event_lock);
 	if (!eventid || eventid == cachepc_last_event_sent) {
 		if (cachepc_event.type == CPC_EVENT_PAUSE)
 			cachepc_pause_vm = false;
-		err = 0;
 		cachepc_last_event_acked = cachepc_last_event_sent;
 	} else {
-		err = 1;
+		err = -EFAULT;
 		CPC_WARN("Acked event (%llu) does not match sent (%llu)\n",
 			eventid, cachepc_last_event_sent);
 	}
diff --git a/cachepc/event.h b/cachepc/event.h
@@ -17,5 +17,5 @@ int cachepc_send_track_page_event(uint64_t gfn_prev, uint64_t gfn, uint64_t reti
 
 bool cachepc_event_is_done(uint64_t id);
 
-int cachepc_handle_poll_event_ioctl(struct cpc_event *user);
-int cachepc_handle_ack_event_ioctl(uint64_t eventid);
+int cachepc_poll_event_ioctl(void __user *arg_user);
+int cachepc_ack_event_ioctl(void __user *arg_user);
diff --git a/cachepc/kvm.c b/cachepc/kvm.c
@@ -110,9 +110,6 @@ static int cachepc_kvm_track_mode_ioctl(void __user *arg_user);
 // static int cachepc_kvm_track_range_end_ioctl(void __user *arg_user);
 // static int cachepc_kvm_track_exec_cur_ioctl(void __user *arg_user);
 
-static int cachepc_kvm_poll_event_ioctl(void __user *arg_user);
-static int cachepc_kvm_ack_event_ioctl(void __user *arg_user);
-
 static int cachepc_kvm_req_pause_ioctl(void __user *arg_user);
 
 void
@@ -586,25 +583,6 @@ cachepc_kvm_track_mode_ioctl(void __user *arg_user)
 // }
 
 int
-cachepc_kvm_poll_event_ioctl(void __user *arg_user)
-{
-	return cachepc_handle_poll_event_ioctl(arg_user);
-}
-
-int
-cachepc_kvm_ack_event_ioctl(void __user *arg_user)
-{
-	uint64_t eventid;
-
-	if (!arg_user) return -EINVAL;
-
-	if (copy_from_user(&eventid, arg_user, sizeof(eventid)))
-		return -EFAULT;
-
-	return cachepc_handle_ack_event_ioctl(eventid);
-}
-
-int
 cachepc_kvm_req_pause_ioctl(void __user *arg_user)
 {
 	if (arg_user) return -EINVAL;
@@ -646,9 +624,9 @@ cachepc_kvm_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
 	case KVM_CPC_TRACK_MODE:
 		return cachepc_kvm_track_mode_ioctl(arg_user);
 	case KVM_CPC_POLL_EVENT:
-		return cachepc_kvm_poll_event_ioctl(arg_user);
+		return cachepc_poll_event_ioctl(arg_user);
 	case KVM_CPC_ACK_EVENT:
-		return cachepc_kvm_ack_event_ioctl(arg_user);
+		return cachepc_ack_event_ioctl(arg_user);
 	// case KVM_CPC_TRACK_PAGE:
 	// 	return cachepc_kvm_track_page_ioctl(arg_user);
 	// case KVM_CPC_TRACK_RANGE_START:
diff --git a/test/kvm-step.c b/test/kvm-step.c
@@ -19,11 +19,11 @@
 #define SECONDARY_CORE 3
 
 static int child;
+static struct cpc_event event;
 
 uint64_t
 monitor(struct kvm *kvm, bool baseline)
 {
-	struct cpc_event event;
 	uint8_t counts[64];
 	int ret;
 
@@ -44,6 +44,8 @@ monitor(struct kvm *kvm, bool baseline)
 		event.step.retinst);
 	print_counts(counts);
 	printf("\n");
+	print_counts_raw(counts);
+	printf("\n");
 
 	ret = ioctl(kvm_dev, KVM_CPC_ACK_EVENT, &event.id);
 	if (ret) err(1, "ioctl KVM_CPC_ACK_EVENT");
@@ -54,6 +56,7 @@ monitor(struct kvm *kvm, bool baseline)
 void
 kill_child(void)
 {
+	printf("Killing vm..\n");
 	kill(child, SIGKILL);
 }
 
@@ -64,7 +67,6 @@ main(int argc, const char **argv)
 	struct guest guest;
 	struct kvm kvm;
 	uint8_t baseline[L1_SETS];
-	struct cpc_event event;
 	uint64_t eventcnt;
 	uint32_t arg;
 	int ret;