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[85.223.141.74]) by smtp.gmail.com with ESMTPSA id j2sm1581215lfm.56.2019.03.22.04.09.22 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 22 Mar 2019 04:09:23 -0700 (PDT) Subject: Re: [Xen-devel][PATCH] Input: xen-kbdfront - signal the backend that we disconnect To: Juergen Gross , xen-devel@lists.xenproject.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, dmitry.torokhov@gmail.com, boris.ostrovsky@oracle.com Cc: Volodymyr_Babchuk@epam.com, Oleksandr Andrushchenko References: <20190315092348.32613-1-andr2000@gmail.com> <32add426-ae36-ecc9-aa3e-6169fe04f231@suse.com> From: Oleksandr Andrushchenko Message-ID: <9b814fc6-d130-ec63-65a1-fbfd957de52b@gmail.com> Date: Fri, 22 Mar 2019 13:09:22 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <32add426-ae36-ecc9-aa3e-6169fe04f231@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/22/19 1:03 PM, Juergen Gross wrote: > On 15/03/2019 10:23, Oleksandr Andrushchenko wrote: >> From: Oleksandr Andrushchenko >> >> While disconnecting from the backend we clean up shared resources >> (event channel, ring buffer), but never let the backend know about >> that. This may lead to inconsistent backend state and/or shared >> resources use. >> Fix this by explicitly letting the backend know that frontend has >> destroyed shared resources by changing its Xen bus state accordingly. >> >> Signed-off-by: Oleksandr Andrushchenko >> --- >> drivers/input/misc/xen-kbdfront.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c >> index 24bc5c5d876f..ecb6e719e0e2 100644 >> --- a/drivers/input/misc/xen-kbdfront.c >> +++ b/drivers/input/misc/xen-kbdfront.c >> @@ -488,6 +488,8 @@ static int xenkbd_connect_backend(struct xenbus_device *dev, >> >> static void xenkbd_disconnect_backend(struct xenkbd_info *info) >> { >> + xenbus_switch_state(info->xbdev, XenbusStateClosing); >> + >> if (info->irq >= 0) >> unbind_from_irqhandler(info->irq, info); >> info->irq = -1; >> > As already stated for the related netfront patch: I'm not sure this > is really what we want. Have you tested xl save/restore or migration > of the guest with your patch applied? Well, it comes out that this is not enough and needs much more work, so please let's abandon this patch > > Juergen Thank you, Oleksandr