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From: Parav Pandit <parav@nvidia.com>
To: Jason Wang <jasowang@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>
Cc: "virtualization@lists.linux-foundation.org" 
	<virtualization@lists.linux-foundation.org>,
	Eli Cohen <elic@nvidia.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: RE: [PATCH linux-next v3 6/6] vdpa_sim_net: Add support for user supported devices
Date: Fri, 15 Jan 2021 06:27:26 +0000
Message-ID: <BY5PR12MB4322309C33E4871C11535F3CDCA70@BY5PR12MB4322.namprd12.prod.outlook.com> (raw)
In-Reply-To: <01213588-d4af-820a-bcf8-c28b8a80c346@redhat.com>



> From: Jason Wang <jasowang@redhat.com>
> Sent: Friday, January 15, 2021 11:09 AM
> 
> 
> On 2021/1/14 下午3:58, Parav Pandit wrote:
> >
> >> From: Jason Wang <jasowang@redhat.com>
> >> Sent: Thursday, January 14, 2021 9:48 AM
> >>
> >> On 2021/1/7 上午11:48, Parav Pandit wrote:
> >>>> From: Michael S. Tsirkin <mst@redhat.com>
> >>>> Sent: Tuesday, January 5, 2021 6:53 PM
> >>>>
> >>>> On Tue, Jan 05, 2021 at 12:30:15PM +0000, Parav Pandit wrote:
> >>>>>> From: Michael S. Tsirkin <mst@redhat.com>
> >>>>>> Sent: Tuesday, January 5, 2021 5:45 PM
> >>>>>>
> >>>>>> On Tue, Jan 05, 2021 at 12:02:33PM +0000, Parav Pandit wrote:
> >>>>>>>> From: Michael S. Tsirkin <mst@redhat.com>
> >>>>>>>> Sent: Tuesday, January 5, 2021 5:19 PM
> >>>>>>>>
> >>>>>>>> On Tue, Jan 05, 2021 at 12:32:03PM +0200, Parav Pandit wrote:
> >>>>>>>>> Enable user to create vdpasim net simulate devices.
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> $ vdpa dev add mgmtdev vdpasim_net name foo2
> >>>>>>>>>
> >>>>>>>>> Show the newly created vdpa device by its name:
> >>>>>>>>> $ vdpa dev show foo2
> >>>>>>>>> foo2: type network mgmtdev vdpasim_net vendor_id 0
> max_vqs 2
> >>>>>>>>> max_vq_size 256
> >>>>>>>>>
> >>>>>>>>> $ vdpa dev show foo2 -jp
> >>>>>>>>> {
> >>>>>>>>>       "dev": {
> >>>>>>>>>           "foo2": {
> >>>>>>>>>               "type": "network",
> >>>>>>>>>               "mgmtdev": "vdpasim_net",
> >>>>>>>>>               "vendor_id": 0,
> >>>>>>>>>               "max_vqs": 2,
> >>>>>>>>>               "max_vq_size": 256
> >>>>>>>>>           }
> >>>>>>>>>       }
> >>>>>>>>> }
> >>>>>>>> I'd like an example of how do device specific (e.g. net
> >>>>>>>> specific) interfaces tie in to this.
> >>>>>>> Not sure I follow your question.
> >>>>>>> Do you mean how to set mac address or mtu of this vdpa device of
> >>>>>>> type
> >>>>>> net?
> >>>>>>> If so, dev add command will be extended shortly in subsequent
> >>>>>>> series to
> >>>>>> set this net specific attributes.
> >>>>>>> (I did mention in the next steps in cover letter).
> >>>>>>>
> >>>>>>>>> +static int __init vdpasim_net_init(void) {
> >>>>>>>>> +	int ret;
> >>>>>>>>> +
> >>>>>>>>> +	if (macaddr) {
> >>>>>>>>> +		mac_pton(macaddr, macaddr_buf);
> >>>>>>>>> +		if (!is_valid_ether_addr(macaddr_buf))
> >>>>>>>>> +			return -EADDRNOTAVAIL;
> >>>>>>>>> +	} else {
> >>>>>>>>> +		eth_random_addr(macaddr_buf);
> >>>>>>>>>    	}
> >>>>>>>> Hmm so all devices start out with the same MAC until changed?
> >>>>>>>> And how is the change effected?
> >>>>>>> Post this patchset and post we have iproute2 vdpa in the tree,
> >>>>>>> will add the
> >>>>>> mac address as the input attribute during "vdpa dev add" command.
> >>>>>>> So that each different vdpa device can have user specified
> >>>>>>> (different) mac
> >>>>>> address.
> >>>>>>
> >>>>>> For now maybe just avoid VIRTIO_NET_F_MAC then for new devices
> >>>> then?
> >>>>> That would require book keeping existing net vdpa_sim devices
> >>>>> created to
> >>>> avoid setting VIRTIO_NET_F_MAC.
> >>>>> Such book keeping code will be short lived anyway.
> >>>>> Not sure if its worth it.
> >>>>> Until now only one device was created. So not sure two vdpa
> >>>>> devices with
> >>>> same mac address will be a real issue.
> >>>>> When we add mac address attribute in add command, at that point
> >>>>> also
> >>>> remove the module parameter macaddr.
> >>>>
> >>>> Will that be mandatory? I'm not to happy with a UAPI we intend to
> >>>> break straight away ...
> >>> No. Specifying mac address shouldn't be mandatory. UAPI wont' be
> >> broken.
> >>
> >>
> >> If it's not mandatory. Does it mean the vDPA parent need to use its
> >> own logic to generate a validate mac? I'm not sure this is what
> >> management (libvirt want).
> >>
> > There are few use cases that I see with PFs, VFs and SFs supporting vdpa
> devices.
> >
> > 1. User wants to use the VF only for vdpa purpose. Here user got the VF
> which was pre-setup by the sysadmin.
> > In this case whatever MAC assigned to the VF can be used by its vdpa
> device.
> > Here, user doesn't need to pass the mac address during vdpa device
> creation time.
> > This is done as the same MAC has been setup in the ACL rules on the switch
> side.
> > Non VDPA users of a VF typically use the VF this way for Netdev and rdma
> functionality.
> > They might continue same way for vdpa application as well.
> > Here VF mac is either set using
> > (a) devlink port function set hw_addr command or using
> > (b) ip link set vf mac
> > So vdpa tool didn't pass the mac. (optional).
> > Though VIRTIO_NET_F_MAC is still valid.
> >
> > 2. User may want to create one or more vdpa device out of the mgmt.
> device.
> > Here user wants to more/full control of all features, overriding what
> sysadmin has setup as MAC of the VF/SF.
> > In this case user will specify the MAC via mgmt tool.
> > (a) This is also used by those vdpa devices which doesn't have eswitch
> offloads.
> > (b) This will work with eswitch offloads as well who does source learning.
> > (c) User chose to use the vdpa device of a VF while VF Netdev and rdma
> device are used by hypervisor for something else as well.
> > VIRTIO_NET_F_MAC remains valid in all 2.{a,b,c}.
> >
> > 3. A  vendor mgmt. device always expects it user to provide mac for its
> vdpa devices.
> > So when it is not provided, it can fail with error message string in extack or
> clear the VIRTIO_NET_F_MAC and let it work using virtio spec's 5.1.5 point 5
> to proceed.
> >
> > As common denominator of all above cases, if QEMU or user pass the MAC
> during creation, it will almost always work.
> > Advance user and QEMU with switchdev mode support who has done
> 1.a/1.b, will omit it.
> > I do not know how deep integration of QEMU exist with the switchdev
> mode support.
> >
> > With that mac, mtu as optional input fields provide the necessary flexibility
> for different stacks to take appropriate shape as they desire.
> 
> 
> Thanks for the clarification. I think we'd better document the above in the
> patch that introduces the mac setting from management API.

Yes. Will do.
Thanks.

  reply index

Thread overview: 79+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-12  6:39 [PATCH 0/7] Introduce vdpa management tool Parav Pandit
2020-11-12  6:39 ` [PATCH 1/7] vdpa: Add missing comment for virtqueue count Parav Pandit
2020-11-12  6:40 ` [PATCH 2/7] vdpa: Use simpler version of ida allocation Parav Pandit
2020-11-12  6:40 ` [PATCH 3/7] vdpa: Extend routine to accept vdpa device name Parav Pandit
2020-11-12  6:40 ` [PATCH 4/7] vdpa: Define vdpa parent device, ops and a netlink interface Parav Pandit
2020-11-12  6:40 ` [PATCH 5/7] vdpa: Enable a user to add and delete a vdpa device Parav Pandit
2020-11-12  6:40 ` [PATCH 6/7] vdpa: Enable user to query vdpa device info Parav Pandit
2020-11-12  6:40 ` [PATCH 7/7] vdpa/vdpa_sim: Enable user to create vdpasim net devices Parav Pandit
2020-11-16  9:41 ` [PATCH 0/7] Introduce vdpa management tool Stefan Hajnoczi
2020-11-17 19:41   ` Parav Pandit
2020-11-16 22:23 ` Jakub Kicinski
2020-11-17 19:51   ` Parav Pandit
2020-12-16  9:13     ` Michael S. Tsirkin
     [not found]       ` <20201216080610.08541f44@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
2020-12-16 16:54         ` Parav Pandit
2020-12-16 19:57           ` Michael S. Tsirkin
2020-12-17 12:13             ` Parav Pandit
2020-11-27  3:53 ` Jason Wang
     [not found]   ` <CACycT3sYScObb9nN3g7L3cesjE7sCZWxZ5_5R1usGU9ePZEeqA@mail.gmail.com>
2020-11-30  3:36     ` [External] " Jason Wang
2020-11-30  7:07       ` Yongji Xie
2020-12-01  6:25         ` Jason Wang
2020-12-01  9:55           ` Yongji Xie
2020-12-01 11:32             ` Parav Pandit
2020-12-01 14:18               ` Yongji Xie
2020-12-01 15:58                 ` Parav Pandit
2020-12-02  3:29                   ` Yongji Xie
2020-12-02  4:53                     ` Parav Pandit
2020-12-02  5:51                       ` Jason Wang
2020-12-02  6:24                         ` Parav Pandit
2020-12-02  7:55                           ` Jason Wang
2020-12-02  9:27                         ` Yongji Xie
2020-12-02  9:21                       ` Yongji Xie
2020-12-02 11:13                         ` Parav Pandit
2020-12-02 13:18                           ` Yongji Xie
2020-12-02  5:48             ` Jason Wang
2020-12-08 22:47   ` David Ahern
2021-01-19  4:21     ` Parav Pandit
2020-12-16  9:16 ` Michael S. Tsirkin
2021-01-04  3:31 ` [PATCH linux-next v2 " Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 1/7] vdpa_sim_net: Make mac address array static Parav Pandit
2021-01-04  7:00     ` Jason Wang
2021-01-04  3:31   ` [PATCH linux-next v2 2/7] vdpa_sim_net: Add module param to disable default vdpa net device Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 3/7] vdpa: Extend routine to accept vdpa device name Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 4/7] vdpa: Define vdpa mgmt device, ops and a netlink interface Parav Pandit
2021-01-04  7:03     ` Jason Wang
2021-01-04  7:24       ` Parav Pandit
2021-01-05  4:10         ` Jason Wang
2021-01-05  6:33           ` Parav Pandit
2021-01-05  8:36             ` Jason Wang
2021-01-04  3:31   ` [PATCH linux-next v2 5/7] vdpa: Enable a user to add and delete a vdpa device Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 6/7] vdpa: Enable user to query vdpa device info Parav Pandit
2021-01-04  3:31   ` [PATCH linux-next v2 7/7] vdpa_sim_net: Add support for user supported devices Parav Pandit
2021-01-04  7:05     ` Jason Wang
2021-01-04  7:21       ` Parav Pandit
2021-01-05  4:06         ` Jason Wang
2021-01-05  6:22           ` Parav Pandit
2021-01-05 10:31 ` [PATCH linux-next v3 0/6] Introduce vdpa management tool Parav Pandit
2021-01-05 10:31   ` [PATCH linux-next v3 1/6] vdpa_sim_net: Make mac address array static Parav Pandit
2021-01-07 13:45     ` Stefano Garzarella
2021-01-05 10:31   ` [PATCH linux-next v3 2/6] vdpa: Extend routine to accept vdpa device name Parav Pandit
2021-01-05 10:32   ` [PATCH linux-next v3 3/6] vdpa: Define vdpa mgmt device, ops and a netlink interface Parav Pandit
2021-01-05 10:32   ` [PATCH linux-next v3 4/6] vdpa: Enable a user to add and delete a vdpa device Parav Pandit
2021-01-05 10:32   ` [PATCH linux-next v3 5/6] vdpa: Enable user to query vdpa device info Parav Pandit
2021-01-05 10:32   ` [PATCH linux-next v3 6/6] vdpa_sim_net: Add support for user supported devices Parav Pandit
2021-01-05 11:48     ` Michael S. Tsirkin
2021-01-05 12:02       ` Parav Pandit
2021-01-05 12:14         ` Michael S. Tsirkin
2021-01-05 12:30           ` Parav Pandit
2021-01-05 13:23             ` Michael S. Tsirkin
2021-01-07  3:48               ` Parav Pandit
2021-01-12  4:14                 ` Parav Pandit
2021-01-14  4:17                 ` Jason Wang
2021-01-14  7:58                   ` Parav Pandit
2021-01-15  5:38                     ` Jason Wang
2021-01-15  6:27                       ` Parav Pandit [this message]
2021-01-19 11:09                         ` Jason Wang
2021-01-20  3:21                           ` Parav Pandit
2021-01-20  3:46                             ` Parav Pandit
2021-01-18 18:03                       ` Parav Pandit
2021-01-20  7:53                         ` Michael S. Tsirkin

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