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From: "Pavel Dovgaluk" <Pavel.Dovgaluk@ispras.ru>
References: <20141126103841.7772.11864.stgit@PASHA-ISP>
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	<5475B3AB.1040402@redhat.com>
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Date: Thu, 27 Nov 2014 12:11:21 +0300
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Subject: Re: [Qemu-devel] [RFC PATCH v5 22/31] timer: introduce new
	QEMU_CLOCK_VIRTUAL_RT clock
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To: 'Paolo Bonzini' <pbonzini@redhat.com>, qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, peter.crosthwaite@xilinx.com, rbilson@qnx.com, alex.bennee@linaro.org, mark.burton@greensocs.com, real@ispras.ru, batuzovk@ispras.ru, maria.klimushenkova@ispras.ru, afaerber@suse.de, fred.konrad@greensocs.com

> From: Paolo Bonzini [mailto:pbonzini@redhat.com]
> On 26/11/2014 11:40, Pavel Dovgalyuk wrote:
> > + * @QEMU_CLOCK_VIRTUAL_RT: realtime clock used for icount warp
> > + *
> > + * This clock runs as a realtime clock, but is used for icount warp
> > + * and thus should be traced with record/replay to make warp =
function
> > + * behave deterministically.
> >   */
>=20
> I think it should also stop/restart across "stop" and "cont" commands,
> similar to QEMU_CLOCK_VIRTUAL.  This is as simple as changing
> get_clock() to cpu_get_clock().
>=20
> This way, QEMU_CLOCK_VIRTUAL_RT is "what QEMU_CLOCK_VIRTUAL does =
without
> -icount".  This makes a lot of sense and can be merged in 2.3
> independent of the rest of the series.

I've updated QEMU to master and started testing changed that you =
proposed.

And one more problem came out here. The problem is related to patch =
60e68042cf70f271308dc6b4b22b609d054af929

It changes x86_cpu_has_work function. And this function instead of just =
checking the CPU state changes it:

-    return ((cs->interrupt_request & (CPU_INTERRUPT_HARD |
-                                      CPU_INTERRUPT_POLL)) &&
+#if !defined(CONFIG_USER_ONLY)
+    if (cs->interrupt_request & CPU_INTERRUPT_POLL) {
+        apic_poll_irq(cpu->apic_state);
+        cpu_reset_interrupt(cs, CPU_INTERRUPT_POLL);
+    }
+#endif
+
+    return ((cs->interrupt_request & CPU_INTERRUPT_HARD) &&

These changes break the deterministic execution, because cpu_has_work() =
may be called at
any moment of the execution.

When POLL interrupt request is processed by x86_cpu_exec_interrupt =
function, as it were before,
everything is ok, because I ensure that these calls occur at the same =
moments in record/replay.

Pavel Dovgalyuk