From 75bbe5e5ec2867f098a31bfd553a1fb084289cc2 Mon Sep 17 00:00:00 2001 From: Pavel Dovgalyuk Date: Fri, 27 May 2022 13:46:13 +0300 Subject: [PATCH] replay: notify vCPU when BH is scheduled vCPU execution should be suspended when new BH is scheduled. This is needed to avoid guest timeouts caused by the long cycles of the execution. In replay mode execution may hang when vCPU sleeps and block event comes to the queue. This patch adds notification which wakes up vCPU or interrupts execution of guest code. Signed-off-by: Pavel Dovgalyuk Reviewed-by: Richard Henderson -- v2: changed first_cpu to current_cpu (suggested by Richard Henderson) v4: moved vCPU notification to aio_bh_enqueue (suggested by Paolo Bonzini) Message-Id: <165364837317.688121.17680519919871405281.stgit@pasha-ThinkPad-X280> Signed-off-by: Paolo Bonzini --- include/sysemu/cpu-timers.h | 1 + softmmu/icount.c | 8 ++++++++ stubs/icount.c | 4 ++++ util/async.c | 8 ++++++++ 4 files changed, 21 insertions(+) diff --git a/include/sysemu/cpu-timers.h b/include/sysemu/cpu-timers.h index ed6ee5c46c..2e786fe7fb 100644 --- a/include/sysemu/cpu-timers.h +++ b/include/sysemu/cpu-timers.h @@ -59,6 +59,7 @@ int64_t icount_round(int64_t count); /* if the CPUs are idle, start accounting real time to virtual clock. */ void icount_start_warp_timer(void); void icount_account_warp_timer(void); +void icount_notify_exit(void); /* * CPU Ticks and Clock diff --git a/softmmu/icount.c b/softmmu/icount.c index 5ca271620d..1cafec5014 100644 --- a/softmmu/icount.c +++ b/softmmu/icount.c @@ -486,3 +486,11 @@ void icount_configure(QemuOpts *opts, Error **errp) qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + NANOSECONDS_PER_SECOND / 10); } + +void icount_notify_exit(void) +{ + if (icount_enabled() && current_cpu) { + qemu_cpu_kick(current_cpu); + qemu_clock_notify(QEMU_CLOCK_VIRTUAL); + } +} diff --git a/stubs/icount.c b/stubs/icount.c index f13c43568b..6df8c2bf7d 100644 --- a/stubs/icount.c +++ b/stubs/icount.c @@ -43,3 +43,7 @@ void icount_account_warp_timer(void) { abort(); } + +void icount_notify_exit(void) +{ +} diff --git a/util/async.c b/util/async.c index 554ba70cca..63434ddae4 100644 --- a/util/async.c +++ b/util/async.c @@ -33,6 +33,7 @@ #include "block/raw-aio.h" #include "qemu/coroutine_int.h" #include "qemu/coroutine-tls.h" +#include "sysemu/cpu-timers.h" #include "trace.h" /***********************************************************/ @@ -84,6 +85,13 @@ static void aio_bh_enqueue(QEMUBH *bh, unsigned new_flags) } aio_notify(ctx); + /* + * Workaround for record/replay. + * vCPU execution should be suspended when new BH is set. + * This is needed to avoid guest timeouts caused + * by the long cycles of the execution. + */ + icount_notify_exit(); } /* Only called from aio_bh_poll() and aio_ctx_finalize() */