[Qemu-devel] [RFC PATCH v3 25/49] replay: interrupts and exceptions

[Pavel Dovgalyuk]

This patch includes modifications of common cpu files. All interrupts and
exceptions occured during recording are written into the replay log.
These events allow correct replaying the execution by kicking cpu thread
when one of these events is found in the log.

Signed-off-by: Pavel Dovgalyuk <address@hidden>
---
 cpu-exec.c               |   14 +++++++++++---
 replay/replay-internal.h |    4 ++++
 replay/replay.c          |   42 ++++++++++++++++++++++++++++++++++++++++++
 replay/replay.h          |   14 ++++++++++++++
 4 files changed, 71 insertions(+), 3 deletions(-)

diff --git a/cpu-exec.c b/cpu-exec.c
index 13c0ec6..fcde7ce 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -23,6 +23,7 @@
 #include "qemu/atomic.h"
 #include "sysemu/qtest.h"
 #include "qemu/main-loop.h"
+#include "replay/replay.h"
 
 void cpu_loop_exit(CPUState *cpu)
 {
@@ -314,8 +315,14 @@ int cpu_exec(CPUArchState *env)
                     ret = cpu->exception_index;
                     break;
 #else
-                    cc->do_interrupt(cpu);
-                    cpu->exception_index = -1;
+                    if (replay_exception()) {
+                        cc->do_interrupt(cpu);
+                        cpu->exception_index = -1;
+                    } else if (!replay_has_interrupt()) {
+                        /* give a chance to iothread in replay mode */
+                        ret = EXCP_REPLAY;
+                        break;
+                    }
 #endif
                 }
             }
@@ -323,7 +330,8 @@ int cpu_exec(CPUArchState *env)
             next_tb = 0; /* force lookup of first TB */
             for(;;) {
                 interrupt_request = cpu->interrupt_request;
-                if (unlikely(interrupt_request)) {
+                if (unlikely((interrupt_request & CPU_INTERRUPT_DEBUG)
+                             || (interrupt_request && replay_interrupt()))) {
                     if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) {
                         /* Mask out external interrupts for this step. */
                         interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK;
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index 6e7d96f..4c8c785 100755
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -15,6 +15,10 @@
 #include <stdio.h>
 #include "sysemu/sysemu.h"
 
+/* for software interrupt */
+#define EVENT_INTERRUPT             15
+/* for emulated exceptions */
+#define EVENT_EXCEPTION             23
 /* for async events */
 #define EVENT_ASYNC                 24
 /* for instruction event */
diff --git a/replay/replay.c b/replay/replay.c
index 10c67f7..6988994 100755
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -158,3 +158,45 @@ uint64_t replay_get_current_step(void)
     }
     return replay_state.current_step;
 }
+
+bool replay_exception(void)
+{
+    if (replay_mode == REPLAY_MODE_RECORD) {
+        replay_save_instructions();
+        replay_put_event(EVENT_EXCEPTION);
+        return true;
+    } else if (replay_mode == REPLAY_MODE_PLAY) {
+        if (skip_async_events(EVENT_EXCEPTION)) {
+            replay_has_unread_data = 0;
+            return true;
+        }
+        return false;
+    }
+
+    return true;
+}
+
+bool replay_interrupt(void)
+{
+    if (replay_mode == REPLAY_MODE_RECORD) {
+        replay_save_instructions();
+        replay_put_event(EVENT_INTERRUPT);
+        return true;
+    } else if (replay_mode == REPLAY_MODE_PLAY) {
+        if (skip_async_events(EVENT_INTERRUPT)) {
+            replay_has_unread_data = 0;
+            return true;
+        }
+        return false;
+    }
+
+    return true;
+}
+
+bool replay_has_interrupt(void)
+{
+    if (replay_mode == REPLAY_MODE_PLAY) {
+        return skip_async_events(EVENT_INTERRUPT);
+    }
+    return false;
+}
diff --git a/replay/replay.h b/replay/replay.h
index b764df7..37edf54 100755
--- a/replay/replay.h
+++ b/replay/replay.h
@@ -35,4 +35,18 @@ bool replay_has_async_request(void);
 /*! Returns non-zero if next event is instruction. */
 bool replay_has_instruction(void);
 
+/* Interrupts and exceptions */
+
+/*! Called by exception handler to write or read
+    exception processing events. */
+bool replay_exception(void);
+/*! Called by interrupt handlers to write or read
+    interrupt processing events.
+    \return true if interrupt should be processed */
+bool replay_interrupt(void);
+/*! Tries to read interrupt event from the file.
+    Returns true, when interrupt request is pending */
+bool replay_has_interrupt(void);
+
+
 #endif