From: Oleksandr Andrushchenko <Oleksandr_Andrushchenko@epam.com>
To: Jan Beulich <jbeulich@suse.com>,
Oleksandr Andrushchenko <andr2000@gmail.com>
Cc: "boris.ostrovsky@oracle.com" <boris.ostrovsky@oracle.com>,
"jgross@suse.com" <jgross@suse.com>,
"julien@xen.org" <julien@xen.org>,
"sstabellini@kernel.org" <sstabellini@kernel.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 1/2] xen-pciback: prepare for the split for stub and PV
Date: Mon, 27 Sep 2021 07:35:33 +0000 [thread overview]
Message-ID: <accd0220-a9d7-145b-6632-9dee085ffc65@epam.com> (raw)
In-Reply-To: <e472468a-625e-6c4d-a9c2-85594e2ff908@suse.com>
On 27.09.21 10:26, Jan Beulich wrote:
> On 27.09.2021 08:58, Oleksandr Andrushchenko wrote:
>> From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
>>
>> Currently PCI backend implements multiple functionalities at a time.
>> To name a few:
>> 1. It is used as a database for assignable PCI devices, e.g. xl
>> pci-assignable-{add|remove|list} manipulates that list. So, whenever
>> the toolstack needs to know which PCI devices can be passed through
>> it reads that from the relevant sysfs entries of the pciback.
>> 2. It is used to hold the unbound PCI devices list, e.g. when passing
>> through a PCI device it needs to be unbound from the relevant device
>> driver and bound to pciback (strictly speaking it is not required
>> that the device is bound to pciback, but pciback is again used as a
>> database of the passed through PCI devices, so we can re-bind the
>> devices back to their original drivers when guest domain shuts down)
>> 3. Device reset for the devices being passed through
>> 4. Para-virtualised use-cases support
>>
>> The para-virtualised part of the driver is not always needed as some
>> architectures, e.g. Arm or x86 PVH Dom0, are not using backend-frontend
>> model for PCI device passthrough. For such use-cases make the very
>> first step in splitting the xen-pciback driver into two parts: Xen
>> PCI stub and PCI PV backend drivers.
>>
>> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
>>
>> ---
>> Changes since v3:
>> - Move CONFIG_XEN_PCIDEV_STUB to the second patch
> I'm afraid this wasn't fully done:
>
>> --- a/drivers/xen/xen-pciback/Makefile
>> +++ b/drivers/xen/xen-pciback/Makefile
>> @@ -1,5 +1,6 @@
>> # SPDX-License-Identifier: GPL-2.0
>> obj-$(CONFIG_XEN_PCIDEV_BACKEND) += xen-pciback.o
>> +obj-$(CONFIG_XEN_PCIDEV_STUB) += xen-pciback.o
> While benign when added here, this addition still doesn't seem to
> belong here.
My bad. So, it seems without CONFIG_XEN_PCIDEV_STUB the change seems
to be non-functional. With CONFIG_XEN_PCIDEV_STUB we fail to build on 32-bit
architectures...
What would be the preference here? Stefano suggested that we still define
CONFIG_XEN_PCIDEV_STUB, but in disabled state, e.g. we add tristate to it
in the second patch
Another option is just to squash the two patches.
>
> Jan
>
next prev parent reply other threads:[~2021-09-27 7:35 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-27 6:58 [PATCH v4 1/2] xen-pciback: prepare for the split for stub and PV Oleksandr Andrushchenko
2021-09-27 6:58 ` [PATCH v4 2/2] xen-pciback: allow compiling on other archs than x86 Oleksandr Andrushchenko
2021-09-27 7:26 ` [PATCH v4 1/2] xen-pciback: prepare for the split for stub and PV Jan Beulich
2021-09-27 7:35 ` Oleksandr Andrushchenko [this message]
2021-09-27 7:48 ` Jan Beulich
2021-09-27 7:54 ` Juergen Gross
2021-09-28 4:18 ` Stefano Stabellini
2021-09-28 4:53 ` Oleksandr Andrushchenko
2021-09-28 6:42 ` Jan Beulich
2021-09-28 6:56 ` Oleksandr Andrushchenko
2021-09-28 6:59 ` Juergen Gross
2021-09-28 7:17 ` Oleksandr Andrushchenko
2021-09-28 7:20 ` Juergen Gross
2021-09-28 7:24 ` Oleksandr Andrushchenko
2021-09-28 7:26 ` Juergen Gross
2021-09-28 7:20 ` Stefano Stabellini
2021-09-28 7:24 ` Oleksandr Andrushchenko
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