From: Oleksandr Andrushchenko <Oleksandr_Andrushchenko@epam.com>
To: Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"boris.ostrovsky@oracle.com" <boris.ostrovsky@oracle.com>,
"julien@xen.org" <julien@xen.org>,
"jbeulich@suse.com" <jbeulich@suse.com>,
Oleksandr Andrushchenko <andr2000@gmail.com>
Subject: Re: [PATCH 2/2] xen-pciback: prepare for the split for stub and PV
Date: Thu, 23 Sep 2021 09:09:56 +0000 [thread overview]
Message-ID: <98e432f0-6be1-6394-1c06-ac5e726c708d@epam.com> (raw)
In-Reply-To: <7880dee9-7372-5a25-db55-018f21e8b08c@suse.com>
On 23.09.21 12:05, Juergen Gross wrote:
> On 23.09.21 11:02, Oleksandr Andrushchenko wrote:
>>
>> On 23.09.21 00:10, Stefano Stabellini wrote:
>>> On Wed, 22 Sep 2021, Oleksandr Andrushchenko wrote:
>>>> --- a/drivers/xen/xen-pciback/xenbus.c
>>>> +++ b/drivers/xen/xen-pciback/xenbus.c
>>>> @@ -743,6 +743,9 @@ const struct xen_pcibk_backend *__read_mostly xen_pcibk_backend;
>>>> int __init xen_pcibk_xenbus_register(void)
>>>> {
>>>> + if (!xen_pcibk_pv_support())
>>>> + return 0;
>>> Is this truly enough to stop the PV backend from initializing? Have you
>>> actually tested it to make sure? If it works, amazing! I am quite happy
>>> about this approach :-)
>>
>> Well, I put some logs into the driver and saw nothing obvious pointing
>>
>> to any backend activities (probably this is also because I don't have any
>>
>> frontend). I see that the xenbus driver is not registered. In XenStore I see:
>>
>> root@dom0:~# xenstore-ls -f | grep pci
>> /local/domain/0/backend/pci = ""
>> /local/domain/0/backend/pci/2 = ""
>> /local/domain/0/backend/pci/2/0 = ""
>> /local/domain/0/backend/pci/2/0/frontend = "/local/domain/2/device/pci/0"
>> /local/domain/0/backend/pci/2/0/frontend-id = "2"
>> /local/domain/0/backend/pci/2/0/online = "1"
>> /local/domain/0/backend/pci/2/0/state = "1"
>> /local/domain/0/backend/pci/2/0/domain = "DomU"
>> /local/domain/0/backend/pci/2/0/key-0 = "0000:03:00.0"
>> /local/domain/0/backend/pci/2/0/dev-0 = "0000:03:00.0"
>> /local/domain/0/backend/pci/2/0/opts-0 = "msitranslate=0,power_mgmt=0,permissive=0,rdm_policy=strict"
>> /local/domain/0/backend/pci/2/0/state-0 = "1"
>> /local/domain/0/backend/pci/2/0/num_devs = "1"
>> /local/domain/2/device/pci = ""
>> /local/domain/2/device/pci/0 = ""
>> /local/domain/2/device/pci/0/backend = "/local/domain/0/backend/pci/2/0"
>> /local/domain/2/device/pci/0/backend-id = "0"
>> /local/domain/2/device/pci/0/state = "1"
>> /libxl/pci = ""
>> /libxl/pci/0000-03-00-0 = ""
>> /libxl/pci/0000-03-00-0/domid = "2"
>>
>> But IIUIC these come from the toolstack
>>
>> @Juergen, do you know how to check if the backend is indeed not running
>>
>> or the above should be enough to prove?
>
> I don't see how the backend could be running without being registered
> with xenbus. It won't receive any watches, so there is no way a
> connection with a frontend could be established.
This is my understanding too, so the only change I've put in patch I removed
register/unregister. It seems this is just enough and the patch should be ok as is
>
>
> Juergen
>
Thank you,
Oleksandr
next prev parent reply other threads:[~2021-09-23 9:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-22 10:14 [PATCH 1/2] xen-pciback: allow compiling on other archs than x86 Oleksandr Andrushchenko
2021-09-22 10:14 ` [PATCH 2/2] xen-pciback: prepare for the split for stub and PV Oleksandr Andrushchenko
2021-09-22 21:10 ` Stefano Stabellini
2021-09-23 9:02 ` Oleksandr Andrushchenko
2021-09-23 9:05 ` Juergen Gross
2021-09-23 9:09 ` Oleksandr Andrushchenko [this message]
2021-09-23 15:48 ` Stefano Stabellini
2021-09-22 21:07 ` [PATCH 1/2] xen-pciback: allow compiling on other archs than x86 Stefano Stabellini
2021-09-23 7:36 ` Oleksandr Andrushchenko
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