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Subject: Re: [PATCH v4 2/3] xen/events: don't unmask an event channel when an
 eoi is pending
To:     Juergen Gross <jgross@suse.com>, xen-devel@lists.xenproject.org,
        linux-kernel@vger.kernel.org, ross.lagerwall@citrix.com
Cc:     Stefano Stabellini <sstabellini@kernel.org>,
        stable@vger.kernel.org, Julien Grall <julien@xen.org>,
        Julien Grall <jgrall@amazon.com>
References: <20210306161833.4552-1-jgross@suse.com>
 <20210306161833.4552-3-jgross@suse.com>
From:   Boris Ostrovsky <boris.ostrovsky@oracle.com>
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On 3/6/21 11:18 AM, Juergen Gross wrote:
> An event channel should be kept masked when an eoi is pending for it.
> When being migrated to another cpu it might be unmasked, though.
>
> In order to avoid this keep three different flags for each event channel
> to be able to distinguish "normal" masking/unmasking from eoi related
> masking/unmasking and temporary masking. The event channel should only
> be able to generate an interrupt if all flags are cleared.
>
> Cc: stable@vger.kernel.org
> Fixes: 54c9de89895e0a36047 ("xen/events: add a new late EOI evtchn framework")
> Reported-by: Julien Grall <julien@xen.org>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> Reviewed-by: Julien Grall <jgrall@amazon.com>
> ---
> V2:
> - introduce a lock around masking/unmasking
> - merge patch 3 into this one (Jan Beulich)
> V4:
> - don't set eoi masking flag in lateeoi_mask_ack_dynirq()


Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>


Ross, are you planning to test this?


-boris