[Qemu-devel] [RFC PATCH v9 16/23] replay: bottom halves

[Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>]

This patch introduces bottom half event for replay queue. It saves the events
into the queue and process them at the checkpoints and instructions execution.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
---
 async.c                  |   24 +++++++++++++++++++++++-
 dma-helpers.c            |    4 +++-
 hw/ide/ahci.c            |    4 +++-
 hw/ide/core.c            |    4 +++-
 hw/timer/arm_timer.c     |    2 +-
 hw/usb/hcd-uhci.c        |    2 +-
 include/block/aio.h      |   18 ++++++++++++++++++
 include/qemu/main-loop.h |    1 +
 main-loop.c              |    5 +++++
 replay/replay-events.c   |   16 ++++++++++++++++
 replay/replay-internal.h |    1 +
 replay/replay.h          |    2 ++
 stubs/replay.c           |    4 ++++
 13 files changed, 81 insertions(+), 6 deletions(-)

diff --git a/async.c b/async.c
index a84f122..91f2ae6 100644
--- a/async.c
+++ b/async.c
@@ -27,6 +27,7 @@
 #include "block/thread-pool.h"
 #include "qemu/main-loop.h"
 #include "qemu/atomic.h"
+#include "replay/replay.h"
 
 /***********************************************************/
 /* bottom halves (can be seen as timers which expire ASAP) */
@@ -39,6 +40,8 @@ struct QEMUBH {
     bool scheduled;
     bool idle;
     bool deleted;
+    bool replay;
+    uint64_t id;
 };
 
 QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
@@ -56,6 +59,21 @@ QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
     return bh;
 }
 
+QEMUBH *aio_bh_new_replay(AioContext *ctx, QEMUBHFunc *cb, void *opaque,
+                          uint64_t id)
+{
+    QEMUBH *bh = aio_bh_new(ctx, cb, opaque);
+    bh->replay = true;
+    bh->id = id;
+    return bh;
+}
+
+void aio_bh_call(void *opaque)
+{
+    QEMUBH *bh = (QEMUBH *)opaque;
+    bh->cb(bh->opaque);
+}
+
 /* Multiple occurrences of aio_bh_poll cannot be called concurrently */
 int aio_bh_poll(AioContext *ctx)
 {
@@ -77,7 +95,11 @@ int aio_bh_poll(AioContext *ctx)
             if (!bh->idle)
                 ret = 1;
             bh->idle = 0;
-            bh->cb(bh->opaque);
+            if (!bh->replay) {
+                aio_bh_call(bh);
+            } else {
+                replay_add_bh_event(bh, bh->id);
+            }
         }
     }
 
diff --git a/dma-helpers.c b/dma-helpers.c
index 6918572..357d7e9 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -13,6 +13,7 @@
 #include "qemu/range.h"
 #include "qemu/thread.h"
 #include "qemu/main-loop.h"
+#include "replay/replay.h"
 
 /* #define DEBUG_IOMMU */
 
@@ -96,7 +97,8 @@ static void continue_after_map_failure(void *opaque)
 {
     DMAAIOCB *dbs = (DMAAIOCB *)opaque;
 
-    dbs->bh = qemu_bh_new(reschedule_dma, dbs);
+    dbs->bh = qemu_bh_new_replay(reschedule_dma, dbs,
+                                 replay_get_current_step());
     qemu_bh_schedule(dbs->bh);
 }
 
diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 5651372..13d7f84 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -33,6 +33,7 @@
 #include "internal.h"
 #include <hw/ide/pci.h>
 #include <hw/ide/ahci.h>
+#include "replay/replay.h"
 
 #define DEBUG_AHCI 0
 
@@ -1243,7 +1244,8 @@ static void ahci_cmd_done(IDEDMA *dma)
 
     if (!ad->check_bh) {
         /* maybe we still have something to process, check later */
-        ad->check_bh = qemu_bh_new(ahci_check_cmd_bh, ad);
+        ad->check_bh = qemu_bh_new_replay(ahci_check_cmd_bh, ad,
+                                          replay_get_current_step());
         qemu_bh_schedule(ad->check_bh);
     }
 }
diff --git a/hw/ide/core.c b/hw/ide/core.c
index ac3f015..d6af700 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -32,6 +32,7 @@
 #include "sysemu/dma.h"
 #include "hw/block/block.h"
 #include "sysemu/block-backend.h"
+#include "replay/replay.h"
 
 #include <hw/ide/internal.h>
 
@@ -448,7 +449,8 @@ BlockAIOCB *ide_issue_trim(BlockBackend *blk,
 
     iocb = blk_aio_get(&trim_aiocb_info, blk, cb, opaque);
     iocb->blk = blk;
-    iocb->bh = qemu_bh_new(ide_trim_bh_cb, iocb);
+    iocb->bh = qemu_bh_new_replay(ide_trim_bh_cb, iocb,
+                                  replay_get_current_step());
     iocb->ret = 0;
     iocb->qiov = qiov;
     iocb->i = -1;
diff --git a/hw/timer/arm_timer.c b/hw/timer/arm_timer.c
index 1452910..97784a0 100644
--- a/hw/timer/arm_timer.c
+++ b/hw/timer/arm_timer.c
@@ -168,7 +168,7 @@ static arm_timer_state *arm_timer_init(uint32_t freq)
     s->freq = freq;
     s->control = TIMER_CTRL_IE;
 
-    bh = qemu_bh_new(arm_timer_tick, s);
+    bh = qemu_bh_new_replay(arm_timer_tick, s, 0);
     s->timer = ptimer_init(bh);
     vmstate_register(NULL, -1, &vmstate_arm_timer, s);
     return s;
diff --git a/hw/usb/hcd-uhci.c b/hw/usb/hcd-uhci.c
index f903de7..47ff9f4 100644
--- a/hw/usb/hcd-uhci.c
+++ b/hw/usb/hcd-uhci.c
@@ -1221,7 +1221,7 @@ static int usb_uhci_common_initfn(PCIDevice *dev)
                               USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL);
         }
     }
-    s->bh = qemu_bh_new(uhci_bh, s);
+    s->bh = qemu_bh_new_replay(uhci_bh, s, 0);
     s->frame_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, uhci_frame_timer, s);
     s->num_ports_vmstate = NB_PORTS;
     QTAILQ_INIT(&s->queues);
diff --git a/include/block/aio.h b/include/block/aio.h
index 82cdf78..ed76b43 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -35,6 +35,8 @@ struct BlockAIOCB {
     const AIOCBInfo *aiocb_info;
     BlockDriverState *bs;
     BlockCompletionFunc *cb;
+    bool replay;
+    uint64_t replay_step;
     void *opaque;
     int refcnt;
 };
@@ -144,6 +146,17 @@ void aio_context_release(AioContext *ctx);
 QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque);
 
 /**
+ * aio_bh_new_replay: Allocate a new bottom half structure for replay.
+ *
+ * This function calls aio_bh_new function and also fills replay parameters
+ * of the BH structure. BH created with this function in record/replay mode
+ * are executed through the replay queue only at checkpoints and instructions
+ * executions.
+ */
+QEMUBH *aio_bh_new_replay(AioContext *ctx, QEMUBHFunc *cb, void *opaque,
+                          uint64_t id);
+
+/**
  * aio_notify: Force processing of pending events.
  *
  * Similar to signaling a condition variable, aio_notify forces
@@ -159,6 +172,11 @@ QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque);
 void aio_notify(AioContext *ctx);
 
 /**
+ * aio_bh_call: Executes callback function of the specified BH.
+ */
+void aio_bh_call(void *opaque);
+
+/**
  * aio_bh_poll: Poll bottom halves for an AioContext.
  *
  * These are internal functions used by the QEMU main loop.
diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
index 62c68c0..f5a98fe 100644
--- a/include/qemu/main-loop.h
+++ b/include/qemu/main-loop.h
@@ -306,6 +306,7 @@ void qemu_iohandler_fill(GArray *pollfds);
 void qemu_iohandler_poll(GArray *pollfds, int rc);
 
 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque);
+QEMUBH *qemu_bh_new_replay(QEMUBHFunc *cb, void *opaque, uint64_t id);
 void qemu_bh_schedule_idle(QEMUBH *bh);
 
 #endif
diff --git a/main-loop.c b/main-loop.c
index 06aad06..87ebad4 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -514,3 +514,8 @@ QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
 {
     return aio_bh_new(qemu_aio_context, cb, opaque);
 }
+
+QEMUBH *qemu_bh_new_replay(QEMUBHFunc *cb, void *opaque, uint64_t id)
+{
+    return aio_bh_new_replay(qemu_aio_context, cb, opaque, id);
+}
diff --git a/replay/replay-events.c b/replay/replay-events.c
index 7b4d773..2fb73be 100755
--- a/replay/replay-events.c
+++ b/replay/replay-events.c
@@ -35,6 +35,9 @@ static bool events_enabled = false;
 static void replay_run_event(Event *event)
 {
     switch (event->event_kind) {
+    case REPLAY_ASYNC_EVENT_BH:
+        aio_bh_call(event->opaque);
+        break;
     default:
         error_report("Replay: invalid async event ID (%d) in the queue",
                     event->event_kind);
@@ -133,10 +136,18 @@ static void replay_save_event(Event *event, int checkpoint)
 
         /* save event-specific data */
         switch (event->event_kind) {
+        case REPLAY_ASYNC_EVENT_BH:
+            replay_put_qword(event->id);
+            break;
         }
     }
 }
 
+void replay_add_bh_event(void *bh, uint64_t id)
+{
+    replay_add_event_internal(REPLAY_ASYNC_EVENT_BH, bh, NULL, id);
+}
+
 /* Called with replay mutex locked */
 void replay_save_events(int checkpoint)
 {
@@ -168,6 +179,11 @@ static Event *replay_read_event(int checkpoint)
 
     /* Events that has not to be in the queue */
     switch (read_event_kind) {
+    case REPLAY_ASYNC_EVENT_BH:
+        if (read_id == -1) {
+            read_id = replay_get_qword();
+        }
+        break;
     default:
         error_report("Unknown ID %d of replay event", read_event_kind);
         exit(1);
diff --git a/replay/replay-internal.h b/replay/replay-internal.h
index fb27b48..91c966c 100755
--- a/replay/replay-internal.h
+++ b/replay/replay-internal.h
@@ -39,6 +39,7 @@ enum ReplayEvents {
 /* Asynchronous events IDs */
 
 enum ReplayAsyncEventKind {
+    REPLAY_ASYNC_EVENT_BH,
     REPLAY_ASYNC_COUNT
 };
 
diff --git a/replay/replay.h b/replay/replay.h
index f4bdb31..0c41f4e 100755
--- a/replay/replay.h
+++ b/replay/replay.h
@@ -95,5 +95,7 @@ bool replay_checkpoint(ReplayCheckpoint checkpoint);
 void replay_disable_events(void);
 /*! Returns true when saving events is enabled */
 bool replay_events_enabled(void);
+/*! Adds BH event to the queue */
+void replay_add_bh_event(void *bh, uint64_t id);
 
 #endif
diff --git a/stubs/replay.c b/stubs/replay.c
index 1be3575..268f3e0 100755
--- a/stubs/replay.c
+++ b/stubs/replay.c
@@ -21,3 +21,7 @@ int runstate_is_running(void)
 {
     return 0;
 }
+
+void replay_add_bh_event(void *bh, uint64_t id)
+{
+}