From: Cornelia Huck <cohuck@redhat.com>
To: Eric Farman <farman@linux.ibm.com>
Cc: Jared Rossi <jrossi@linux.ibm.com>,
Halil Pasic <pasic@linux.ibm.com>,
linux-s390@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: [RFC PATCH v2 0/4] vfio-ccw: Fix interrupt handling for HALT/CLEAR
Date: Tue, 26 May 2020 11:55:41 +0200 [thread overview]
Message-ID: <20200526115541.4a11accc.cohuck@redhat.com> (raw)
In-Reply-To: <20200513142934.28788-1-farman@linux.ibm.com>
On Wed, 13 May 2020 16:29:30 +0200
Eric Farman <farman@linux.ibm.com> wrote:
> There was some suggestion earlier about locking the FSM, but I'm not
> seeing any problems with that. Rather, what I'm noticing is that the
> flow between a synchronous START and asynchronous HALT/CLEAR have
> different impacts on the FSM state. Consider:
>
> CPU 1 CPU 2
>
> SSCH (set state=CP_PENDING)
> INTERRUPT (set state=IDLE)
> CSCH (no change in state)
> SSCH (set state=CP_PENDING)
> INTERRUPT (set state=IDLE)
> INTERRUPT (set state=IDLE)
A different question (not related to how we want to fix this): How
easily can you trigger this bug? Is this during normal testing with a
bit of I/O stress, or do you have a special test case?
next prev parent reply other threads:[~2020-05-26 9:55 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 14:29 [RFC PATCH v2 0/4] vfio-ccw: Fix interrupt handling for HALT/CLEAR Eric Farman
2020-05-13 14:29 ` [RFC PATCH v2 1/4] vfio-ccw: Do not reset FSM state for unsolicited interrupts Eric Farman
2020-05-13 14:29 ` [RFC PATCH v2 2/4] vfio-ccw: Utilize scsw actl to serialize start operations Eric Farman
2020-05-13 14:29 ` [RFC PATCH v2 3/4] vfio-ccw: Expand SCSW usage to HALT and CLEAR Eric Farman
2020-05-13 14:29 ` [RFC PATCH v2 4/4] vfio-ccw: Clean up how to react to a failed START Eric Farman
2020-05-14 13:46 ` [RFC PATCH v2 0/4] vfio-ccw: Fix interrupt handling for HALT/CLEAR Halil Pasic
2020-05-15 13:09 ` Eric Farman
2020-05-15 14:55 ` Halil Pasic
2020-05-15 15:58 ` Cornelia Huck
2020-05-15 17:41 ` Halil Pasic
2020-05-15 18:19 ` Eric Farman
2020-05-15 18:12 ` Eric Farman
2020-05-15 18:37 ` Halil Pasic
2020-05-18 22:01 ` Eric Farman
2020-05-15 19:35 ` Halil Pasic
2020-05-18 16:09 ` Cornelia Huck
2020-05-18 21:57 ` Eric Farman
2020-05-19 11:23 ` Cornelia Huck
2020-05-18 22:09 ` Halil Pasic
2020-05-19 11:36 ` Cornelia Huck
2020-05-19 12:10 ` Halil Pasic
2020-05-26 9:55 ` Cornelia Huck [this message]
2020-05-26 11:08 ` Eric Farman
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