Re: [Patch V3 2/3] usb: Introduce Xen pvUSB frontend (xen hcd)
From: Juergen Gross
Date: Tue Jun 16 2015 - 10:56:49 EST
On 06/16/2015 04:45 PM, Greg KH wrote:
On Tue, Jun 16, 2015 at 04:32:34PM +0200, Juergen Gross wrote:
Introduces the Xen pvUSB frontend. With pvUSB it is possible for a Xen
domU to communicate with a USB device assigned to that domU. The
communication is all done via the pvUSB backend in a driver domain
(usually Dom0) which is owner of the physical device.
The pvUSB frontend is a USB hcd for a virtual USB host connector.
The code is taken from the pvUSB implementation in Xen done by Fujitsu
based on Linux kernel 2.6.18.
Changes from the original version are:
- port to upstream kernel
- put all code in just one source file
- move module to appropriate location in kernel tree
- adapt to Linux style guide
- minor code modifications to increase readability
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
drivers/usb/host/Kconfig | 11 +
drivers/usb/host/Makefile | 1 +
drivers/usb/host/xen-hcd.c | 1638 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 1650 insertions(+)
create mode 100644 drivers/usb/host/xen-hcd.c
diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index 197a6a3..3361b4b 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -788,3 +788,14 @@ config USB_HCD_TEST_MODE
This option is of interest only to developers who need to validate
their USB hardware designs. It is not needed for normal use. If
unsure, say N.
+
+config USB_XEN_HCD
+ tristate "Xen usb virtual host driver"
+ depends on XEN
+ select XEN_XENBUS_FRONTEND
+ help
+ The Xen usb virtual host driver serves as a frontend driver enabling
+ a Xen guest system to access USB Devices passed through to the guest
+ by the Xen host (usually Dom0).
+ Only needed if the kernel is running in a Xen guest and generic
+ access to a USB device is needed.
diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
index 65b0b6a..3779696 100644
--- a/drivers/usb/host/Makefile
+++ b/drivers/usb/host/Makefile
@@ -75,3 +75,4 @@ obj-$(CONFIG_USB_HCD_SSB) += ssb-hcd.o
obj-$(CONFIG_USB_FUSBH200_HCD) += fusbh200-hcd.o
obj-$(CONFIG_USB_FOTG210_HCD) += fotg210-hcd.o
obj-$(CONFIG_USB_MAX3421_HCD) += max3421-hcd.o
+obj-$(CONFIG_USB_XEN_HCD) += xen-hcd.o
diff --git a/drivers/usb/host/xen-hcd.c b/drivers/usb/host/xen-hcd.c
new file mode 100644
index 0000000..9da2856
--- /dev/null
+++ b/drivers/usb/host/xen-hcd.c
@@ -0,0 +1,1638 @@
+/*
+ * xen-hcd.c
+ *
+ * Xen USB Virtual Host Controller driver
+ *
+ * Copyright (C) 2009, FUJITSU LABORATORIES LTD.
+ * Author: Noboru Iwamatsu <n_iwamatsu@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Or, by your choice:
+ *
+ * When distributed separately from the Linux kernel or incorporated into
+ * other software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/list.h>
+#include <linux/usb/hcd.h>
+#include <linux/io.h>
+
+#include <xen/xen.h>
+#include <xen/xenbus.h>
+#include <xen/grant_table.h>
+#include <xen/events.h>
+#include <xen/page.h>
+
+#include <xen/interface/io/usbif.h>
+
+/* Private per-URB data */
+struct urb_priv {
+ struct list_head list;
+ struct urb *urb;
+ int req_id; /* RING_REQUEST id for submitting */
+ int unlink_req_id; /* RING_REQUEST id for unlinking */
+ int status;
+ unsigned unlinked:1; /* dequeued marker */
+};
+
+/* virtual roothub port status */
+struct rhport_status {
+ __u32 status;
+ unsigned resuming:1; /* in resuming */
+ unsigned c_connection:1; /* connection changed */
+ unsigned long timeout;
+};
+
+/* status of attached device */
+struct vdevice_status {
+ int devnum;
+ enum usb_device_state status;
+ enum usb_device_speed speed;
+};
+
+/* RING request shadow */
+struct usb_shadow {
+ struct xenusb_urb_request req;
+ struct urb *urb;
+};
+
+struct xenhcd_info {
+ /* Virtual Host Controller has 4 urb queues */
+ struct list_head pending_submit_list;
+ struct list_head pending_unlink_list;
+ struct list_head in_progress_list;
+ struct list_head giveback_waiting_list;
+
+ spinlock_t lock;
+
+ /* timer that kick pending and giveback waiting urbs */
+ struct timer_list watchdog;
+ unsigned long actions;
+
+ /* virtual root hub */
+ int rh_numports;
+ struct rhport_status ports[XENUSB_MAX_PORTNR];
+ struct vdevice_status devices[XENUSB_MAX_PORTNR];
+
+ /* Xen related staff */
+ struct xenbus_device *xbdev;
+ int urb_ring_ref;
+ int conn_ring_ref;
+ struct xenusb_urb_front_ring urb_ring;
+ struct xenusb_conn_front_ring conn_ring;
+
+ unsigned int evtchn;
+ unsigned int irq;
+ struct usb_shadow shadow[XENUSB_URB_RING_SIZE];
+ unsigned shadow_free;
+};
+
+#define GRANT_INVALID_REF 0
+
+#define XENHCD_RING_JIFFIES (HZ/200)
+#define XENHCD_SCAN_JIFFIES 1
+
+enum xenhcd_timer_action {
+ TIMER_RING_WATCHDOG,
+ TIMER_SCAN_PENDING_URBS,
+};
+
+static struct kmem_cache *xenhcd_urbp_cachep;
+
+static inline struct xenhcd_info *xenhcd_hcd_to_info(struct usb_hcd *hcd)
+{
+ return (struct xenhcd_info *)hcd->hcd_priv;
+}
+
+static inline struct usb_hcd *xenhcd_info_to_hcd(struct xenhcd_info *info)
+{
+ return container_of((void *)info, struct usb_hcd, hcd_priv);
+}
+
+static inline void xenhcd_timer_action_done(struct xenhcd_info *info,
+ enum xenhcd_timer_action action)
+{
+ clear_bit(action, &info->actions);
+}
+
+static void xenhcd_timer_action(struct xenhcd_info *info,
+ enum xenhcd_timer_action action)
+{
+ if (timer_pending(&info->watchdog) &&
+ test_bit(TIMER_SCAN_PENDING_URBS, &info->actions))
+ return;
+
+ if (!test_and_set_bit(action, &info->actions)) {
+ unsigned long t;
+
+ switch (action) {
+ case TIMER_RING_WATCHDOG:
+ t = XENHCD_RING_JIFFIES;
+ break;
+ default:
+ t = XENHCD_SCAN_JIFFIES;
+ break;
+ }
+ mod_timer(&info->watchdog, t + jiffies);
+ }
+}
+
+static ssize_t xenhcd_show_statistics(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct usb_hcd *hcd;
+ struct xenhcd_info *info;
+ unsigned long flags;
+ unsigned size;
+
+ hcd = dev_get_drvdata(dev);
+ info = xenhcd_hcd_to_info(hcd);
+
+ spin_lock_irqsave(&info->lock, flags);
+
+ size = scnprintf(buf, PAGE_SIZE, "bus %s, device %s\n%s\n"
+ "xenhcd, hcd state %d\n",
+ hcd->self.controller->bus->name,
+ dev_name(hcd->self.controller), hcd->product_desc,
+ hcd->state);
+
+ spin_unlock_irqrestore(&info->lock, flags);
+
+ return size;
+}
+
+static DEVICE_ATTR(statistics, S_IRUGO, xenhcd_show_statistics, NULL);
DEVICE_ATTR_RO() please.
Okay.
As you are adding new sysfs files, we need Documentation/ABI/ entries.
Okay.
Also note that I will reject this sysfs file for the obvious reasons
that it violates the one-value-per-file sysfs rule. Nice try to sneak
this one by, don't ever do that again.
Lesson learned.
Hmm, I'm beginning to question the value of that file. May be I should
just throw it away.
Thanks for the quick feedback.
Juergen
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