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From: Jorgen Hansen <jhansen@vmware.com>
To: 'Stefano Garzarella' <sgarzare@redhat.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jason Wang <jasowang@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Dexuan Cui <decui@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Sasha Levin <sashal@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	"virtualization@lists.linux-foundation.org" 
	<virtualization@lists.linux-foundation.org>
Subject: RE: [PATCH net-next 12/14] vsock/vmci: register vmci_transport only when VMCI guest/host are active
Date: Mon, 11 Nov 2019 16:27:28 +0000
Message-ID: <MWHPR05MB3376266BC6AE9E6E0B75F1A1DA740@MWHPR05MB3376.namprd05.prod.outlook.com> (raw)
In-Reply-To: <20191023095554.11340-13-sgarzare@redhat.com>

> From: Stefano Garzarella [mailto:sgarzare@redhat.com]
> Sent: Wednesday, October 23, 2019 11:56 AM
> 
> To allow other transports to be loaded with vmci_transport,
> we register the vmci_transport as G2H or H2G only when a VMCI guest
> or host is active.
> 
> To do that, this patch adds a callback registered in the vmci driver
> that will be called when a new host or guest become active.
> This callback will register the vmci_transport in the VSOCK core.
> If the transport is already registered, we ignore the error coming
> from vsock_core_register().

So today this is mainly an issue for the VMCI vsock transport, because
VMCI autoloads with vsock (and with this solution it can continue to
do that, so none of our old products break due to changed behavior,
which is great). Shouldn't vhost behave similar, so that any module
that registers a h2g transport only does so if it is in active use?


> --- a/drivers/misc/vmw_vmci/vmci_host.c
> +++ b/drivers/misc/vmw_vmci/vmci_host.c
> @@ -108,6 +108,11 @@ bool vmci_host_code_active(void)
>  	     atomic_read(&vmci_host_active_users) > 0);
>  }
> 
> +int vmci_host_users(void)
> +{
> +	return atomic_read(&vmci_host_active_users);
> +}
> +
>  /*
>   * Called on open of /dev/vmci.
>   */
> @@ -338,6 +343,8 @@ static int vmci_host_do_init_context(struct
> vmci_host_dev *vmci_host_dev,
>  	vmci_host_dev->ct_type = VMCIOBJ_CONTEXT;
>  	atomic_inc(&vmci_host_active_users);
> 
> +	vmci_call_vsock_callback(true);
> +

Since we don't unregister the transport if user count drops back to 0, we could
just call this the first time, a VM is powered on after the module is loaded.

>  	retval = 0;
> 
>  out:


  parent reply index

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-23  9:55 [PATCH net-next 00/14] vsock: add multi-transports support Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 01/14] vsock/vmci: remove unused VSOCK_DEFAULT_CONNECT_TIMEOUT Stefano Garzarella
2019-10-30 14:54   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 02/14] vsock: remove vm_sockets_get_local_cid() Stefano Garzarella
2019-10-30 14:55   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 03/14] vsock: remove include/linux/vm_sockets.h file Stefano Garzarella
2019-10-30 14:57   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 04/14] vsock: add 'transport' member in the struct vsock_sock Stefano Garzarella
2019-10-30 14:57   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 05/14] vsock/virtio: add transport parameter to the virtio_transport_reset_no_sock() Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 06/14] vsock: add 'struct vsock_sock *' param to vsock_core_get_transport() Stefano Garzarella
2019-10-30 15:01   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 07/14] vsock: handle buffer_size sockopts in the core Stefano Garzarella
2019-10-27  8:08   ` Stefan Hajnoczi
2019-10-30 15:08   ` Jorgen Hansen
2019-10-31  8:50     ` Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 08/14] vsock: add vsock_create_connected() called by transports Stefano Garzarella
2019-10-27  8:12   ` Stefan Hajnoczi
2019-10-30 15:12   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 09/14] vsock: move vsock_insert_unbound() in the vsock_create() Stefano Garzarella
2019-10-30 15:12   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 10/14] hv_sock: set VMADDR_CID_HOST in the hvs_remote_addr_init() Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 11/14] vsock: add multi-transports support Stefano Garzarella
2019-10-23 15:08   ` Stefano Garzarella
2019-10-30 15:40     ` Jorgen Hansen
2019-10-31  8:54       ` Stefano Garzarella
2019-11-11 13:53   ` Jorgen Hansen
2019-11-11 17:17     ` Stefano Garzarella
2019-11-12  9:59       ` Jorgen Hansen
2019-11-12 10:36         ` Stefano Garzarella
2019-11-13 14:30           ` Jorgen Hansen
2019-11-13 16:38             ` Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 12/14] vsock/vmci: register vmci_transport only when VMCI guest/host are active Stefano Garzarella
2019-10-27  8:17   ` Stefan Hajnoczi
2019-10-29 16:35     ` Stefano Garzarella
2019-11-04 10:10   ` Stefano Garzarella
2019-11-11 16:27   ` Jorgen Hansen [this message]
2019-11-11 17:30     ` Stefano Garzarella
2019-11-12 10:03       ` Jorgen Hansen
2019-11-12 10:42         ` Stefano Garzarella
2019-10-23  9:55 ` [PATCH net-next 13/14] vsock: prevent transport modules unloading Stefano Garzarella
2019-11-11 16:36   ` Jorgen Hansen
2019-10-23  9:55 ` [PATCH net-next 14/14] vsock: fix bind() behaviour taking care of CID Stefano Garzarella
2019-11-11 16:53   ` Jorgen Hansen
2019-10-27  8:01 ` [PATCH net-next 00/14] vsock: add multi-transports support Stefan Hajnoczi
2019-10-29 16:27   ` Stefano Garzarella

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