From: fred.konrad@greensocs.com
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, quintela@redhat.com,
mark.burton@greensocs.com, dgilbert@redhat.com,
amit.shah@redhat.com, pbonzini@redhat.com, vilanova@ac.upc.edu,
fred.konrad@greensocs.com
Subject: [Qemu-devel] [RFC PATCH v4 12/13] cexe: synchronize icount on the next event.
Date: Wed, 25 Jun 2014 10:26:47 +0200 [thread overview]
Message-ID: <1403684808-23248-13-git-send-email-fred.konrad@greensocs.com> (raw)
In-Reply-To: <1403684808-23248-1-git-send-email-fred.konrad@greensocs.com>
From: KONRAD Frederic <fred.konrad@greensocs.com>
We don't want to warp on host clock as it is not deterministic for replay.
So this patch warp icount on the next QEMU_VIRTUAL_CLOCK event if reverse
execution is enabled.
The normal behaviour is kept when reverse execution is disabled.
Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
---
cpus.c | 19 +++++++++++++++++--
include/qemu/timer.h | 8 ++++++++
include/reverse-execution.h | 2 ++
main-loop.c | 10 ++++++++++
stubs/Makefile.objs | 1 +
stubs/cexe-stub.c | 32 ++++++++++++++++++++++++++++++++
stubs/cpu-get-icount.c | 8 ++++++++
7 files changed, 78 insertions(+), 2 deletions(-)
create mode 100644 stubs/cexe-stub.c
diff --git a/cpus.c b/cpus.c
index e86045e..77d4700 100644
--- a/cpus.c
+++ b/cpus.c
@@ -321,8 +321,10 @@ static int64_t qemu_icount_round(int64_t count)
return (count + (1 << icount_time_shift) - 1) >> icount_time_shift;
}
-static void icount_warp_rt(void *opaque)
+void icount_warp_rt(void *opaque)
{
+ int64_t next_vm_deadline = -1;
+
/* The icount_warp_timer is rescheduled soon after vm_clock_warp_start
* changes from -1 to another value, so the race here is okay.
*/
@@ -330,6 +332,13 @@ static void icount_warp_rt(void *opaque)
return;
}
+ if (cexe_is_enabled()) {
+ /*
+ * We need this because the standard warp_delta is not deterministic.
+ */
+ next_vm_deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
+ }
+
seqlock_write_lock(&timers_state.vm_clock_seqlock);
if (runstate_is_running()) {
int64_t clock = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
@@ -346,7 +355,13 @@ static void icount_warp_rt(void *opaque)
int64_t delta = cur_time - cur_icount;
warp_delta = MIN(warp_delta, delta);
}
- timers_state.qemu_icount_bias += warp_delta;
+ if (cexe_is_enabled()) {
+ if (next_vm_deadline > 0) {
+ timers_state.qemu_icount_bias += next_vm_deadline;
+ }
+ } else {
+ timers_state.qemu_icount_bias += warp_delta;
+ }
}
vm_clock_warp_start = -1;
seqlock_write_unlock(&timers_state.vm_clock_seqlock);
diff --git a/include/qemu/timer.h b/include/qemu/timer.h
index 0ae7f28..de2641a 100644
--- a/include/qemu/timer.h
+++ b/include/qemu/timer.h
@@ -754,6 +754,14 @@ int64_t cpu_get_icount(int with_bias);
int64_t cpu_get_clock(void);
int64_t cpu_icount_to_ns(int64_t icount);
+/**
+ * void icount_warp_rt:
+ *
+ * Move icount to the realtime clock or to the next QEMU_VIRTUAL_CLOCK event
+ * when reverse execution is enabled.
+ */
+void icount_warp_rt(void *opaque);
+
/*******************************************/
/* host CPU ticks (if available) */
diff --git a/include/reverse-execution.h b/include/reverse-execution.h
index bf42003..739572e 100644
--- a/include/reverse-execution.h
+++ b/include/reverse-execution.h
@@ -25,6 +25,8 @@
#ifndef REVERSE_EXECUTION
#define REVERSE_EXECUTION
+#include "qom/cpu.h"
+
void cexe_setup(void);
void cexe_step_backward(CPUState *cpu, uint64_t steps);
void cexe_stop_stepping_back_mode(void);
diff --git a/main-loop.c b/main-loop.c
index 8a85493..6130438 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -34,6 +34,8 @@
#include "qemu/compatfd.h"
+#include "reverse-execution.h"
+
/* If we have signalfd, we mask out the signals we want to handle and then
* use signalfd to listen for them. We rely on whatever the current signal
* handler is to dispatch the signals when we receive them.
@@ -489,6 +491,14 @@ int main_loop_wait(int nonblocking)
qemu_clock_run_all_timers();
+ /*
+ * Sometimes deadlock can appears because there is no pending event on
+ * virtual clock.
+ */
+ if (cexe_is_enabled()) {
+ icount_warp_rt(NULL);
+ }
+
return ret;
}
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index 528e161..5e362f6 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -39,3 +39,4 @@ stub-obj-$(CONFIG_WIN32) += fd-register.o
stub-obj-y += cpus.o
stub-obj-y += kvm.o
stub-obj-y += qmp_pc_dimm_device_list.o
+stub-obj-y += cexe-stub.o
diff --git a/stubs/cexe-stub.c b/stubs/cexe-stub.c
new file mode 100644
index 0000000..7723998
--- /dev/null
+++ b/stubs/cexe-stub.c
@@ -0,0 +1,32 @@
+/*
+ * cexe-stub.c
+ *
+ * Copyright (C) 2014 : GreenSocs Ltd
+ * http://www.greensocs.com/ , email: info@greensocs.com
+ *
+ * Developed by :
+ * Frederic Konrad <fred.konrad@greensocs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <stdbool.h>
+
+bool cexe_is_enabled(void);
+
+bool cexe_is_enabled(void)
+{
+ return false;
+}
diff --git a/stubs/cpu-get-icount.c b/stubs/cpu-get-icount.c
index 1968de7..231e659 100644
--- a/stubs/cpu-get-icount.c
+++ b/stubs/cpu-get-icount.c
@@ -7,3 +7,11 @@ int64_t cpu_get_icount(int with_bias)
{
abort();
}
+
+void icount_warp_rt(void *opaque)
+{
+ /*
+ * Should not happen, as cexe_is_enabled() always return false.
+ */
+ abort();
+}
--
1.9.0
next prev parent reply other threads:[~2014-06-25 8:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-25 8:26 [Qemu-devel] [RFC PATCH v4 00/13] Reverse execution fred.konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 01/13] icount: put icount variables into TimerState fred.konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 02/13] migration: migrate icount fields fred.konrad
2014-06-25 12:17 ` Juan Quintela
2014-06-25 15:17 ` Frederic Konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 03/13] migration: make qemu_savevm_state public fred.konrad
2014-06-25 12:18 ` Juan Quintela
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 04/13] icount: introduce icount timer fred.konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 05/13] icount: check for icount clock deadline when cpu loop exits fred.konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 06/13] icount: make icount extra computed on icount clock as well fred.konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 07/13] timer: add cpu_icount_to_ns function fred.konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 08/13] trace-events: add reverse-execution events fred.konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 09/13] introduce reverse execution mechanism fred.konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 10/13] gdbstub: allow reverse execution in gdb stub fred.konrad
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 11/13] cpu-exec: trigger a debug request when rexec stops fred.konrad
2014-06-25 8:26 ` fred.konrad [this message]
2014-06-25 8:26 ` [Qemu-devel] [RFC PATCH v4 13/13] cexe: allow to enable reverse execution fred.konrad
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