Re: [PATCH V9 8/9] vdpasim: vDPA device simulator

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	KVM list <kvm@vger.kernel.org>,
	virtualization@lists.linux-foundation.org,
	netdev <netdev@vger.kernel.org>,
	Jason Gunthorpe <jgg@mellanox.com>,
	maxime.coquelin@redhat.com, cunming.liang@intel.com,
	zhihong.wang@intel.com, rob.miller@broadcom.com,
	xiao.w.wang@intel.com, lingshan.zhu@intel.com,
	eperezma@redhat.com, lulu@redhat.com, parav@mellanox.com,
	kevin.tian@intel.com, stefanha@redhat.com,
	Randy Dunlap <rdunlap@infradead.org>,
	Christoph Hellwig <hch@infradead.org>,
	aadam@redhat.com, Jiri Pirko <jiri@mellanox.com>,
	shahafs@mellanox.com, hanand@xilinx.com,
	Martin Habets <mhabets@solarflare.com>,
	gdawar@xilinx.com, saugatm@xilinx.com, vmireyno@marvell.com,
	zhangweining@ruijie.com.cn
Subject: Re: [PATCH V9 8/9] vdpasim: vDPA device simulator
Date: Fri, 10 Apr 2020 09:45:09 +0200	[thread overview]
Message-ID: <CAMuHMdUis3O_mJKOb2s=_=Zs61iHus5Aq74N3-xs7kmjN+egoQ@mail.gmail.com> (raw)
In-Reply-To: <20200326140125.19794-9-jasowang@redhat.com>

Hi Jason,

On Thu, Mar 26, 2020 at 3:07 PM Jason Wang <jasowang@redhat.com> wrote:
> This patch implements a software vDPA networking device. The datapath
> is implemented through vringh and workqueue. The device has an on-chip
> IOMMU which translates IOVA to PA. For kernel virtio drivers, vDPA
> simulator driver provides dma_ops. For vhost driers, set_map() methods
> of vdpa_config_ops is implemented to accept mappings from vhost.
>
> Currently, vDPA device simulator will loopback TX traffic to RX. So
> the main use case for the device is vDPA feature testing, prototyping
> and development.
>
> Note, there's no management API implemented, a vDPA device will be
> registered once the module is probed. We need to handle this in the
> future development.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

This is now commit 2c53d0f64c06f458 ("vdpasim: vDPA device simulator").

> --- a/drivers/virtio/vdpa/Kconfig
> +++ b/drivers/virtio/vdpa/Kconfig
> @@ -5,3 +5,22 @@ config VDPA
>           Enable this module to support vDPA device that uses a
>           datapath which complies with virtio specifications with
>           vendor specific control path.
> +
> +menuconfig VDPA_MENU
> +       bool "VDPA drivers"
> +       default n

    *
    * VDPA drivers
    *
    VDPA drivers (VDPA_MENU) [N/y/?] (NEW) ?

    There is no help available for this option.
    Symbol: VDPA_MENU [=n]
    Type  : bool
    Defined at drivers/vdpa/Kconfig:9
     Prompt: VDPA drivers
     Location:
       -> Device Drivers

I think this deserves a help text, so users know if they want to enable this
option or not.

I had a quick look, but couldn't find the meaning of "vdpa" in the whole kernel
source tree.

Thanks!

> +
> +if VDPA_MENU
> +
> +config VDPA_SIM
> +       tristate "vDPA device simulator"
> +       depends on RUNTIME_TESTING_MENU
> +       select VDPA
> +       select VHOST_RING
> +       default n
> +       help
> +         vDPA networking device simulator which loop TX traffic back
> +         to RX. This device is used for testing, prototyping and
> +         development of vDPA.
> +
> +endif # VDPA_MENU

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds