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[212.216.181.31]) by smtp.gmail.com with ESMTPSA id z9sm20176624wrv.1.2019.11.04.02.10.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Nov 2019 02:10:13 -0800 (PST) Date: Mon, 4 Nov 2019 11:10:10 +0100 From: Stefano Garzarella To: Jorgen Hansen Cc: "Michael S. Tsirkin" , kvm@vger.kernel.org, Greg Kroah-Hartman , Jason Wang , "David S. Miller" , Dexuan Cui , Haiyang Zhang , Sasha Levin , linux-kernel@vger.kernel.org, Arnd Bergmann , Stefan Hajnoczi , linux-hyperv@vger.kernel.org, "K. Y. Srinivasan" , Stephen Hemminger , virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Subject: Re: [PATCH net-next 12/14] vsock/vmci: register vmci_transport only when VMCI guest/host are active Message-ID: <20191104101010.we3nsgh4gxiu4vh5@steredhat.homenet.telecomitalia.it> References: <20191023095554.11340-1-sgarzare@redhat.com> <20191023095554.11340-13-sgarzare@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191023095554.11340-13-sgarzare@redhat.com> User-Agent: NeoMutt/20180716 Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org Hi Jorgen, I'm preparing the v2, but first, if you have time, I'd like to have a comment from you on this patch that modifies a bit vmci. Thank you very much, Stefano On Wed, Oct 23, 2019 at 11:55:52AM +0200, Stefano Garzarella wrote: > 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(). > > Cc: Jorgen Hansen > Signed-off-by: Stefano Garzarella > --- > drivers/misc/vmw_vmci/vmci_driver.c | 50 +++++++++++++++++++++++++++++ > drivers/misc/vmw_vmci/vmci_driver.h | 2 ++ > drivers/misc/vmw_vmci/vmci_guest.c | 2 ++ > drivers/misc/vmw_vmci/vmci_host.c | 7 ++++ > include/linux/vmw_vmci_api.h | 2 ++ > net/vmw_vsock/vmci_transport.c | 29 +++++++++++------ > 6 files changed, 82 insertions(+), 10 deletions(-) > > diff --git a/drivers/misc/vmw_vmci/vmci_driver.c b/drivers/misc/vmw_vmci/vmci_driver.c > index 819e35995d32..195afbd7edc1 100644 > --- a/drivers/misc/vmw_vmci/vmci_driver.c > +++ b/drivers/misc/vmw_vmci/vmci_driver.c > @@ -28,6 +28,9 @@ MODULE_PARM_DESC(disable_guest, > static bool vmci_guest_personality_initialized; > static bool vmci_host_personality_initialized; > > +static DEFINE_MUTEX(vmci_vsock_mutex); /* protects vmci_vsock_transport_cb */ > +static vmci_vsock_cb vmci_vsock_transport_cb; > + > /* > * vmci_get_context_id() - Gets the current context ID. > * > @@ -45,6 +48,53 @@ u32 vmci_get_context_id(void) > } > EXPORT_SYMBOL_GPL(vmci_get_context_id); > > +/* > + * vmci_register_vsock_callback() - Register the VSOCK vmci_transport callback. > + * > + * The callback will be called every time a new host or guest become active, > + * or if they are already active when this function is called. > + * To unregister the callback, call this function with NULL parameter. > + * > + * Returns 0 on success. -EBUSY if a callback is already registered. > + */ > +int vmci_register_vsock_callback(vmci_vsock_cb callback) > +{ > + int err = 0; > + > + mutex_lock(&vmci_vsock_mutex); > + > + if (vmci_vsock_transport_cb && callback) { > + err = -EBUSY; > + goto out; > + } > + > + vmci_vsock_transport_cb = callback; > + > + if (!vmci_vsock_transport_cb) > + goto out; > + > + if (vmci_guest_code_active()) > + vmci_vsock_transport_cb(false); > + > + if (vmci_host_users() > 0) > + vmci_vsock_transport_cb(true); > + > +out: > + mutex_unlock(&vmci_vsock_mutex); > + return err; > +} > +EXPORT_SYMBOL_GPL(vmci_register_vsock_callback); > + > +void vmci_call_vsock_callback(bool is_host) > +{ > + mutex_lock(&vmci_vsock_mutex); > + > + if (vmci_vsock_transport_cb) > + vmci_vsock_transport_cb(is_host); > + > + mutex_unlock(&vmci_vsock_mutex); > +} > + > static int __init vmci_drv_init(void) > { > int vmci_err; > diff --git a/drivers/misc/vmw_vmci/vmci_driver.h b/drivers/misc/vmw_vmci/vmci_driver.h > index aab81b67670c..990682480bf6 100644 > --- a/drivers/misc/vmw_vmci/vmci_driver.h > +++ b/drivers/misc/vmw_vmci/vmci_driver.h > @@ -36,10 +36,12 @@ extern struct pci_dev *vmci_pdev; > > u32 vmci_get_context_id(void); > int vmci_send_datagram(struct vmci_datagram *dg); > +void vmci_call_vsock_callback(bool is_host); > > int vmci_host_init(void); > void vmci_host_exit(void); > bool vmci_host_code_active(void); > +int vmci_host_users(void); > > int vmci_guest_init(void); > void vmci_guest_exit(void); > diff --git a/drivers/misc/vmw_vmci/vmci_guest.c b/drivers/misc/vmw_vmci/vmci_guest.c > index 7a84a48c75da..cc8eeb361fcd 100644 > --- a/drivers/misc/vmw_vmci/vmci_guest.c > +++ b/drivers/misc/vmw_vmci/vmci_guest.c > @@ -637,6 +637,8 @@ static int vmci_guest_probe_device(struct pci_dev *pdev, > vmci_dev->iobase + VMCI_CONTROL_ADDR); > > pci_set_drvdata(pdev, vmci_dev); > + > + vmci_call_vsock_callback(false); > return 0; > > err_free_irq: > diff --git a/drivers/misc/vmw_vmci/vmci_host.c b/drivers/misc/vmw_vmci/vmci_host.c > index 833e2bd248a5..ff3c396146ff 100644 > --- 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); > + > retval = 0; > > out: > diff --git a/include/linux/vmw_vmci_api.h b/include/linux/vmw_vmci_api.h > index acd9fafe4fc6..f28907345c80 100644 > --- a/include/linux/vmw_vmci_api.h > +++ b/include/linux/vmw_vmci_api.h > @@ -19,6 +19,7 @@ > struct msghdr; > typedef void (vmci_device_shutdown_fn) (void *device_registration, > void *user_data); > +typedef void (*vmci_vsock_cb) (bool is_host); > > int vmci_datagram_create_handle(u32 resource_id, u32 flags, > vmci_datagram_recv_cb recv_cb, > @@ -37,6 +38,7 @@ int vmci_doorbell_destroy(struct vmci_handle handle); > int vmci_doorbell_notify(struct vmci_handle handle, u32 priv_flags); > u32 vmci_get_context_id(void); > bool vmci_is_context_owner(u32 context_id, kuid_t uid); > +int vmci_register_vsock_callback(vmci_vsock_cb callback); > > int vmci_event_subscribe(u32 event, > vmci_event_cb callback, void *callback_data, > diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c > index 2eb3f16d53e7..04437f822d82 100644 > --- a/net/vmw_vsock/vmci_transport.c > +++ b/net/vmw_vsock/vmci_transport.c > @@ -2053,19 +2053,22 @@ static bool vmci_check_transport(struct vsock_sock *vsk) > return vsk->transport == &vmci_transport; > } > > -static int __init vmci_transport_init(void) > +void vmci_vsock_transport_cb(bool is_host) > { > - int features = VSOCK_TRANSPORT_F_DGRAM | VSOCK_TRANSPORT_F_H2G; > - int cid; > - int err; > + int features; > > - cid = vmci_get_context_id(); > + if (is_host) > + features = VSOCK_TRANSPORT_F_H2G; > + else > + features = VSOCK_TRANSPORT_F_G2H; > > - if (cid == VMCI_INVALID_ID) > - return -EINVAL; > + vsock_core_register(&vmci_transport, features); > +} > > - if (cid != VMCI_HOST_CONTEXT_ID) > - features |= VSOCK_TRANSPORT_F_G2H; > +static int __init vmci_transport_init(void) > +{ > + int features = VSOCK_TRANSPORT_F_DGRAM; > + int err; > > /* Create the datagram handle that we will use to send and receive all > * VSocket control messages for this context. > @@ -2079,7 +2082,6 @@ static int __init vmci_transport_init(void) > pr_err("Unable to create datagram handle. (%d)\n", err); > return vmci_transport_error_to_vsock_error(err); > } > - > err = vmci_event_subscribe(VMCI_EVENT_QP_RESUMED, > vmci_transport_qp_resumed_cb, > NULL, &vmci_transport_qp_resumed_sub_id); > @@ -2094,8 +2096,14 @@ static int __init vmci_transport_init(void) > if (err < 0) > goto err_unsubscribe; > > + err = vmci_register_vsock_callback(vmci_vsock_transport_cb); > + if (err < 0) > + goto err_unregister; > + > return 0; > > +err_unregister: > + vsock_core_unregister(&vmci_transport); > err_unsubscribe: > vmci_event_unsubscribe(vmci_transport_qp_resumed_sub_id); > err_destroy_stream_handle: > @@ -2121,6 +2129,7 @@ static void __exit vmci_transport_exit(void) > vmci_transport_qp_resumed_sub_id = VMCI_INVALID_ID; > } > > + vmci_register_vsock_callback(NULL); > vsock_core_unregister(&vmci_transport); > } > module_exit(vmci_transport_exit); > -- > 2.21.0 > --