linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Leon Romanovsky <leon@kernel.org>
To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
Cc: Max Gurtovoy <mgurtovoy@nvidia.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
	"alex.williamson@redhat.com" <alex.williamson@redhat.com>,
	"jgg@nvidia.com" <jgg@nvidia.com>, Linuxarm <linuxarm@huawei.com>,
	liulongfang <liulongfang@huawei.com>,
	"Zengtao (B)" <prime.zeng@hisilicon.com>,
	yuzenghui <yuzenghui@huawei.com>,
	Jonathan Cameron <jonathan.cameron@huawei.com>,
	"Wangzhou (B)" <wangzhou1@hisilicon.com>
Subject: Re: [RFC v2 1/4] hisi-acc-vfio-pci: add new vfio_pci driver for HiSilicon ACC devices
Date: Mon, 5 Jul 2021 21:27:37 +0300	[thread overview]
Message-ID: <YONPGcwjGH+gImDj@unreal> (raw)
In-Reply-To: <834a009bba0d4db1b7a1c32e8f20611d@huawei.com>

On Mon, Jul 05, 2021 at 10:18:59AM +0000, Shameerali Kolothum Thodi wrote:
> 
> 
> > -----Original Message-----
> > From: Max Gurtovoy [mailto:mgurtovoy@nvidia.com]
> > Sent: 05 July 2021 10:42
> > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>;
> > Leon Romanovsky <leon@kernel.org>
> > Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org;
> > linux-crypto@vger.kernel.org; alex.williamson@redhat.com; jgg@nvidia.com;
> > Linuxarm <linuxarm@huawei.com>; liulongfang <liulongfang@huawei.com>;
> > Zengtao (B) <prime.zeng@hisilicon.com>; yuzenghui
> > <yuzenghui@huawei.com>; Jonathan Cameron
> > <jonathan.cameron@huawei.com>; Wangzhou (B) <wangzhou1@hisilicon.com>
> > Subject: Re: [RFC v2 1/4] hisi-acc-vfio-pci: add new vfio_pci driver for HiSilicon
> > ACC devices
> > 
> > 
> > On 7/5/2021 11:47 AM, Shameerali Kolothum Thodi wrote:
> > >
> > >> -----Original Message-----
> > >> From: Leon Romanovsky [mailto:leon@kernel.org]
> > >> Sent: 04 July 2021 08:04
> > >> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> > >> Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org;
> > >> linux-crypto@vger.kernel.org; alex.williamson@redhat.com;
> > jgg@nvidia.com;
> > >> mgurtovoy@nvidia.com; Linuxarm <linuxarm@huawei.com>; liulongfang
> > >> <liulongfang@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>;
> > >> yuzenghui <yuzenghui@huawei.com>; Jonathan Cameron
> > >> <jonathan.cameron@huawei.com>; Wangzhou (B)
> > <wangzhou1@hisilicon.com>
> > >> Subject: Re: [RFC v2 1/4] hisi-acc-vfio-pci: add new vfio_pci driver for
> > HiSilicon
> > >> ACC devices
> > >>
> > >> On Fri, Jul 02, 2021 at 10:58:46AM +0100, Shameer Kolothum wrote:
> > >>> Add a vendor-specific vfio_pci driver for HiSilicon ACC devices.
> > >>> This will be extended in follow-up patches to add support for
> > >>> vfio live migration feature.
> > >>>
> > >>> Signed-off-by: Shameer Kolothum
> > >> <shameerali.kolothum.thodi@huawei.com>
> > >>> ---
> > >>>   drivers/vfio/pci/Kconfig             |   9 +++
> > >>>   drivers/vfio/pci/Makefile            |   2 +
> > >>>   drivers/vfio/pci/hisi_acc_vfio_pci.c | 100
> > +++++++++++++++++++++++++++
> > >>>   3 files changed, 111 insertions(+)
> > >>>   create mode 100644 drivers/vfio/pci/hisi_acc_vfio_pci.c
> > >> <...>
> > >>
> > >>> +static const struct vfio_device_ops hisi_acc_vfio_pci_ops = {
> > >>> +	.name		= "hisi-acc-vfio-pci",
> > >>> +	.open		= hisi_acc_vfio_pci_open,
> > >>> +	.release	= vfio_pci_core_release,
> > >>> +	.ioctl		= vfio_pci_core_ioctl,
> > >>> +	.read		= vfio_pci_core_read,
> > >>> +	.write		= vfio_pci_core_write,
> > >>> +	.mmap		= vfio_pci_core_mmap,
> > >>> +	.request	= vfio_pci_core_request,
> > >>> +	.match		= vfio_pci_core_match,
> > >>> +	.reflck_attach	= vfio_pci_core_reflck_attach,
> > >> I don't remember what was proposed in vfio-pci-core conversion patches,
> > >> but would expect that default behaviour is to fallback to vfio_pci_core_*
> > API
> > >> if ".release/.ioctl/e.t.c" are not redefined.
> > > Yes, that would be nice, but don't think it does that in latest(v4).
> > >
> > > Hi Max,
> > > Could we please consider fall back to the core defaults, may be check and
> > assign defaults
> > > in vfio_pci_core_register_device() ?
> > 
> > I don't see why we should do this.
> > 
> > vfio_pci_core.ko is just a library driver. It shouldn't decide for the
> > vendor driver ops.
> > 
> > If a vendor driver would like to use its helper functions - great.
> > 
> > If it wants to override it - great.
> > 
> > If it wants to leave some op as NULL - it can do it also.
> 
> Based on the documentation of the vfio_device_ops callbacks,
> It looks like we already have a precedence in the case of reflck_attach
> callback where it uses the vfio core default one, if it is not implemented.

The reflck_attach pattern is pretty common pattern in the kernel to provide fallback.

> 
> Also I would imagine that in majority use cases the vendor drivers will be
> defaulting to core functions. 

Right, this is whole idea of having core functionality in one place, if
vendor wants/needs, he will overwrite.

> 
> I think, in any case, it would be good to update the Documentation based on
> which way we end up doing this.

The request to update Documentation can be seen as an example of
choosing not-good API decisions. Expectation to see all drivers to
use same callbacks with same vfio-core function calls sounds strange
to me.

Thanks

> 
> Thanks,
> Shameer 
> 
>  
> > 
> > 
> > >
> > > Thanks,
> > > Shameer

  reply	other threads:[~2021-07-05 18:27 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-02  9:58 [RFC v2 0/4] vfio/hisilicon: add acc live migration driver Shameer Kolothum
2021-07-02  9:58 ` [RFC v2 1/4] hisi-acc-vfio-pci: add new vfio_pci driver for HiSilicon ACC devices Shameer Kolothum
2021-07-02 20:29   ` Alex Williamson
2021-07-05  7:20     ` Shameerali Kolothum Thodi
2021-07-04  7:03   ` Leon Romanovsky
2021-07-05  8:47     ` Shameerali Kolothum Thodi
2021-07-05  9:41       ` Max Gurtovoy
2021-07-05 10:18         ` Shameerali Kolothum Thodi
2021-07-05 18:27           ` Leon Romanovsky [this message]
2021-07-05 18:32             ` Jason Gunthorpe
2021-07-06  3:59               ` Leon Romanovsky
2021-07-06  4:39               ` Christoph Hellwig
2021-07-06 11:51                 ` Jason Gunthorpe
2021-07-02  9:58 ` [RFC v2 2/4] hisi_acc_vfio_pci: Override ioctl method to limit BAR2 region size Shameer Kolothum
2021-07-02 20:29   ` Alex Williamson
2021-07-05  7:22     ` Shameerali Kolothum Thodi
2021-07-02  9:58 ` [RFC v2 3/4] crypto: hisilicon/qm - Export mailbox functions for common use Shameer Kolothum
2021-07-04  9:34   ` Max Gurtovoy
2021-07-05 10:23     ` Shameerali Kolothum Thodi
2021-07-02  9:58 ` [RFC v2 4/4] hisi_acc_vfio_pci: Add support for vfio live migration Shameer Kolothum
2022-02-02 13:14 ` [RFC v2 0/4] vfio/hisilicon: add acc live migration driver Jason Gunthorpe
2022-02-02 14:34   ` Shameerali Kolothum Thodi
2022-02-02 15:39     ` Jason Gunthorpe
2022-02-02 16:10       ` Shameerali Kolothum Thodi
2022-02-02 17:03         ` Jason Gunthorpe
2022-02-02 19:05           ` Joao Martins
2022-02-03 15:18             ` Jason Gunthorpe
2022-02-04 19:53               ` Joao Martins
2022-02-04 23:07                 ` Jason Gunthorpe
2022-02-11 17:28                   ` Joao Martins
2022-02-11 17:49                     ` Jason Gunthorpe
2022-02-11 21:43                       ` Joao Martins
2022-02-12  0:01                         ` Jason Gunthorpe
2022-02-14 13:34                           ` Joao Martins
2022-02-14 14:06                             ` Jason Gunthorpe
2022-02-15 16:00                               ` Joao Martins
2022-02-15 16:21                                 ` Jason Gunthorpe
2022-02-22 11:55                                   ` Joao Martins
2022-02-23  1:03                                     ` Jason Gunthorpe
2022-02-25 19:18                                       ` Joao Martins
2022-02-25 20:44                                         ` Jason Gunthorpe
2022-02-28 13:01                                           ` Joao Martins
2022-02-28 21:01                                             ` Jason Gunthorpe
2022-03-01 13:06                                               ` Joao Martins
2022-03-01 13:54                                                 ` Jason Gunthorpe
2022-03-01 14:27                                                   ` Joao Martins
2022-03-11 13:51                                             ` iommufd(+vfio-compat) dirty tracking (Was: Re: [RFC v2 0/4] vfio/hisilicon: add acc live migration driver) Joao Martins
2022-03-15 19:29                                               ` Jason Gunthorpe
2022-03-16 16:36                                                 ` iommufd(+vfio-compat) dirty tracking Joao Martins
2022-03-16 20:37                                                   ` Joao Martins
2022-03-18 17:12                                                     ` Joao Martins
2022-03-18 17:34                                                       ` Jason Gunthorpe
2022-02-02 17:30     ` [RFC v2 0/4] vfio/hisilicon: add acc live migration driver Alex Williamson
2022-02-02 18:04       ` Jason Gunthorpe
2022-02-18 16:37 ` Jason Gunthorpe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YONPGcwjGH+gImDj@unreal \
    --to=leon@kernel.org \
    --cc=alex.williamson@redhat.com \
    --cc=jgg@nvidia.com \
    --cc=jonathan.cameron@huawei.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxarm@huawei.com \
    --cc=liulongfang@huawei.com \
    --cc=mgurtovoy@nvidia.com \
    --cc=prime.zeng@hisilicon.com \
    --cc=shameerali.kolothum.thodi@huawei.com \
    --cc=wangzhou1@hisilicon.com \
    --cc=yuzenghui@huawei.com \
    --subject='Re: [RFC v2 1/4] hisi-acc-vfio-pci: add new vfio_pci driver for HiSilicon ACC devices' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).