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Subject[RFC PATCH 17/17] kvm: Add guest-side support for VBUS
Date
This adds a driver to interface between the host VBUS support, and the
guest-vbus bus model.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
---
arch/x86/Kconfig | 9 +
drivers/Makefile | 1
drivers/vbus/proxy/Makefile | 2
drivers/vbus/proxy/kvm.c | 726 +++++++++++++++++++++++++++++++++++++++++++
4 files changed, 738 insertions(+), 0 deletions(-)
create mode 100644 drivers/vbus/proxy/Makefile
create mode 100644 drivers/vbus/proxy/kvm.c
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 91fefd5..8661495 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -451,6 +451,15 @@ config KVM_GUEST_DYNIRQ
depends on KVM_GUEST
default y

+config KVM_GUEST_VBUS
+ tristate "KVM virtual-bus (VBUS) guest-side support"
+ depends on KVM_GUEST
+ select VBUS_DRIVERS
+ default y
+ ---help---
+ This option enables guest-side support for accessing virtual-bus
+ devices.
+
source "arch/x86/lguest/Kconfig"

config PARAVIRT
diff --git a/drivers/Makefile b/drivers/Makefile
index 98fab51..4f2cb93 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -107,3 +107,4 @@ obj-$(CONFIG_VIRTIO) += virtio/
obj-$(CONFIG_STAGING) += staging/
obj-y += platform/
obj-$(CONFIG_VBUS_DEVICES) += vbus/devices/
+obj-$(CONFIG_VBUS_DRIVERS) += vbus/proxy/
diff --git a/drivers/vbus/proxy/Makefile b/drivers/vbus/proxy/Makefile
new file mode 100644
index 0000000..c18d58d
--- /dev/null
+++ b/drivers/vbus/proxy/Makefile
@@ -0,0 +1,2 @@
+kvm-guest-vbus-objs += kvm.o
+obj-$(CONFIG_KVM_GUEST_VBUS) += kvm-guest-vbus.o
diff --git a/drivers/vbus/proxy/kvm.c b/drivers/vbus/proxy/kvm.c
new file mode 100644
index 0000000..82e28b4
--- /dev/null
+++ b/drivers/vbus/proxy/kvm.c
@@ -0,0 +1,726 @@
+/*
+ * Copyright (C) 2009 Novell. All Rights Reserved.
+ *
+ * Author:
+ * Gregory Haskins <ghaskins@novell.com>
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ *
+ * 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, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/vbus.h>
+#include <linux/kvm_para.h>
+#include <linux/kvm.h>
+#include <linux/mm.h>
+#include <linux/ioq.h>
+#include <linux/interrupt.h>
+#include <linux/kvm_para.h>
+#include <linux/kvm_guest.h>
+#include <linux/vbus_client.h>
+#include <linux/vbus_driver.h>
+
+MODULE_AUTHOR("Gregory Haskins");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1");
+
+static int kvm_vbus_hypercall(unsigned long nr, void *data, unsigned long len)
+{
+ return kvm_hypercall3(KVM_HC_VBUS, nr, __pa(data), len);
+}
+
+struct kvm_vbus {
+ spinlock_t lock;
+ struct ioq eventq;
+ struct kvm_vbus_event *ring;
+ int irq;
+};
+
+static struct kvm_vbus kvm_vbus;
+
+struct kvm_vbus_device {
+ char type[VBUS_MAX_DEVTYPE_LEN];
+ u64 handle;
+ struct list_head shms;
+ struct vbus_device_proxy vdev;
+};
+
+/*
+ * -------------------
+ * common routines
+ * -------------------
+ */
+
+struct kvm_vbus_device *
+to_dev(struct vbus_device_proxy *vdev)
+{
+ return container_of(vdev, struct kvm_vbus_device, vdev);
+}
+
+static void
+_signal_init(struct shm_signal *signal, struct shm_signal_desc *desc,
+ struct shm_signal_ops *ops)
+{
+ desc->magic = SHM_SIGNAL_MAGIC;
+ desc->ver = SHM_SIGNAL_VER;
+
+ shm_signal_init(signal);
+
+ signal->locale = shm_locality_north;
+ signal->ops = ops;
+ signal->desc = desc;
+}
+
+/*
+ * -------------------
+ * _signal
+ * -------------------
+ */
+
+struct _signal {
+ struct kvm_vbus *kvbus;
+ struct shm_signal signal;
+ u64 handle;
+ struct rb_node node;
+ struct list_head list;
+};
+
+static struct _signal *
+to_signal(struct shm_signal *signal)
+{
+ return container_of(signal, struct _signal, signal);
+}
+
+static struct _signal *
+node_to_signal(struct rb_node *node)
+{
+ return container_of(node, struct _signal, node);
+}
+
+static int
+_signal_inject(struct shm_signal *signal)
+{
+ struct _signal *_signal = to_signal(signal);
+
+ kvm_vbus_hypercall(KVM_VBUS_OP_SHMSIGNAL,
+ &_signal->handle, sizeof(_signal->handle));
+
+ return 0;
+}
+
+static void
+_signal_release(struct shm_signal *signal)
+{
+ struct _signal *_signal = to_signal(signal);
+
+ kfree(_signal);
+}
+
+static struct shm_signal_ops _signal_ops = {
+ .inject = _signal_inject,
+ .release = _signal_release,
+};
+
+/*
+ * -------------------
+ * vbus_device_proxy routines
+ * -------------------
+ */
+
+static int
+kvm_vbus_device_open(struct vbus_device_proxy *vdev, int version, int flags)
+{
+ struct kvm_vbus_device *dev = to_dev(vdev);
+ struct vbus_deviceopen params;
+ int ret;
+
+ if (dev->handle)
+ return -EINVAL;
+
+ params.devid = vdev->id;
+ params.version = version;
+
+ ret = kvm_vbus_hypercall(KVM_VBUS_OP_DEVOPEN,
+ &params, sizeof(params));
+ if (ret < 0)
+ return ret;
+
+ dev->handle = params.handle;
+
+ return 0;
+}
+
+static int
+kvm_vbus_device_close(struct vbus_device_proxy *vdev, int flags)
+{
+ struct kvm_vbus_device *dev = to_dev(vdev);
+ unsigned long iflags;
+ int ret;
+
+ if (!dev->handle)
+ return -EINVAL;
+
+ spin_lock_irqsave(&kvm_vbus.lock, iflags);
+
+ while (!list_empty(&dev->shms)) {
+ struct _signal *_signal;
+
+ _signal = list_first_entry(&dev->shms, struct _signal, list);
+
+ list_del(&_signal->list);
+
+ spin_unlock_irqrestore(&kvm_vbus.lock, iflags);
+ shm_signal_put(&_signal->signal);
+ spin_lock_irqsave(&kvm_vbus.lock, iflags);
+ }
+
+ spin_unlock_irqrestore(&kvm_vbus.lock, iflags);
+
+ /*
+ * The DEVICECLOSE will implicitly close all of the shm on the
+ * host-side, so there is no need to do an explicit per-shm
+ * hypercall
+ */
+ ret = kvm_vbus_hypercall(KVM_VBUS_OP_DEVCLOSE,
+ &dev->handle, sizeof(dev->handle));
+
+ if (ret < 0)
+ printk(KERN_ERR "KVM-VBUS: Error closing device %s/%lld: %d\n",
+ vdev->type, vdev->id, ret);
+
+ dev->handle = 0;
+
+ return 0;
+}
+
+static int
+kvm_vbus_device_shm(struct vbus_device_proxy *vdev, int id, int prio,
+ void *ptr, size_t len,
+ struct shm_signal_desc *sdesc, struct shm_signal **signal,
+ int flags)
+{
+ struct kvm_vbus_device *dev = to_dev(vdev);
+ struct _signal *_signal = NULL;
+ struct vbus_deviceshm params;
+ unsigned long iflags;
+ int ret;
+
+ if (!dev->handle)
+ return -EINVAL;
+
+ params.devh = dev->handle;
+ params.id = id;
+ params.flags = flags;
+ params.datap = (u64)__pa(ptr);
+ params.len = len;
+
+ if (signal) {
+ /*
+ * The signal descriptor must be embedded within the
+ * provided ptr
+ */
+ if (!sdesc
+ || (len < sizeof(*sdesc))
+ || ((void *)sdesc < ptr)
+ || ((void *)sdesc > (ptr + len - sizeof(*sdesc))))
+ return -EINVAL;
+
+ _signal = kzalloc(sizeof(*_signal), GFP_KERNEL);
+ if (!_signal)
+ return -ENOMEM;
+
+ _signal_init(&_signal->signal, sdesc, &_signal_ops);
+
+ /*
+ * take another reference for the host. This is dropped
+ * by a SHMCLOSE event
+ */
+ shm_signal_get(&_signal->signal);
+
+ params.signal.offset = (u64)sdesc - (u64)ptr;
+ params.signal.prio = prio;
+ params.signal.cookie = (u64)_signal;
+
+ } else
+ params.signal.offset = -1; /* yes, this is a u32, but its ok */
+
+ ret = kvm_vbus_hypercall(KVM_VBUS_OP_DEVSHM,
+ &params, sizeof(params));
+ if (ret < 0) {
+ if (_signal) {
+ /*
+ * We held two references above, so we need to drop
+ * both of them
+ */
+ shm_signal_put(&_signal->signal);
+ shm_signal_put(&_signal->signal);
+ }
+
+ return ret;
+ }
+
+ if (signal) {
+ _signal->handle = params.handle;
+
+ spin_lock_irqsave(&kvm_vbus.lock, iflags);
+
+ list_add_tail(&_signal->list, &dev->shms);
+
+ spin_unlock_irqrestore(&kvm_vbus.lock, iflags);
+
+ shm_signal_get(&_signal->signal);
+ *signal = &_signal->signal;
+ }
+
+ return 0;
+}
+
+static int
+kvm_vbus_device_call(struct vbus_device_proxy *vdev, u32 func, void *data,
+ size_t len, int flags)
+{
+ struct kvm_vbus_device *dev = to_dev(vdev);
+ struct vbus_devicecall params = {
+ .devh = dev->handle,
+ .func = func,
+ .datap = (u64)__pa(data),
+ .len = len,
+ .flags = flags,
+ };
+
+ if (!dev->handle)
+ return -EINVAL;
+
+ return kvm_vbus_hypercall(KVM_VBUS_OP_DEVCALL, &params, sizeof(params));
+}
+
+static void
+kvm_vbus_device_release(struct vbus_device_proxy *vdev)
+{
+ struct kvm_vbus_device *_dev = to_dev(vdev);
+
+ kvm_vbus_device_close(vdev, 0);
+
+ kfree(_dev);
+}
+
+struct vbus_device_proxy_ops kvm_vbus_device_ops = {
+ .open = kvm_vbus_device_open,
+ .close = kvm_vbus_device_close,
+ .shm = kvm_vbus_device_shm,
+ .call = kvm_vbus_device_call,
+ .release = kvm_vbus_device_release,
+};
+
+/*
+ * -------------------
+ * vbus events
+ * -------------------
+ */
+
+static void
+event_devadd(struct kvm_vbus_add_event *event)
+{
+ int ret;
+ struct kvm_vbus_device *new = kzalloc(sizeof(*new), GFP_KERNEL);
+ if (!new) {
+ printk(KERN_ERR "KVM_VBUS: Out of memory on add_event\n");
+ return;
+ }
+
+ INIT_LIST_HEAD(&new->shms);
+
+ memcpy(new->type, event->type, VBUS_MAX_DEVTYPE_LEN);
+ new->vdev.type = new->type;
+ new->vdev.id = event->id;
+ new->vdev.ops = &kvm_vbus_device_ops;
+
+ sprintf(new->vdev.dev.bus_id, "%lld", event->id);
+
+ ret = vbus_device_proxy_register(&new->vdev);
+ if (ret < 0)
+ panic("failed to register device %lld(%s): %d\n",
+ event->id, event->type, ret);
+}
+
+static void
+event_devdrop(struct kvm_vbus_handle_event *event)
+{
+ struct vbus_device_proxy *dev = vbus_device_proxy_find(event->handle);
+
+ if (!dev) {
+ printk(KERN_WARNING "KVM-VBUS: devdrop failed: %lld\n",
+ event->handle);
+ return;
+ }
+
+ vbus_device_proxy_unregister(dev);
+}
+
+static void
+event_shmsignal(struct kvm_vbus_handle_event *event)
+{
+ struct _signal *_signal = (struct _signal *)event->handle;
+
+ _shm_signal_wakeup(&_signal->signal);
+}
+
+static void
+event_shmclose(struct kvm_vbus_handle_event *event)
+{
+ struct _signal *_signal = (struct _signal *)event->handle;
+
+ /*
+ * This reference was taken during the DEVICESHM call
+ */
+ shm_signal_put(&_signal->signal);
+}
+
+/*
+ * -------------------
+ * eventq routines
+ * -------------------
+ */
+
+static struct ioq_notifier eventq_notifier;
+
+static int __init
+eventq_init(int qlen)
+{
+ struct ioq_iterator iter;
+ int ret;
+ int i;
+
+ kvm_vbus.ring = kzalloc(sizeof(struct kvm_vbus_event) * qlen,
+ GFP_KERNEL);
+ if (!kvm_vbus.ring)
+ return -ENOMEM;
+
+ /*
+ * We want to iterate on the "valid" index. By default the iterator
+ * will not "autoupdate" which means it will not hypercall the host
+ * with our changes. This is good, because we are really just
+ * initializing stuff here anyway. Note that you can always manually
+ * signal the host with ioq_signal() if the autoupdate feature is not
+ * used.
+ */
+ ret = ioq_iter_init(&kvm_vbus.eventq, &iter, ioq_idxtype_valid, 0);
+ BUG_ON(ret < 0);
+
+ /*
+ * Seek to the tail of the valid index (which should be our first
+ * item since the queue is brand-new)
+ */
+ ret = ioq_iter_seek(&iter, ioq_seek_tail, 0, 0);
+ BUG_ON(ret < 0);
+
+ /*
+ * Now populate each descriptor with an empty vbus_event and mark it
+ * valid
+ */
+ for (i = 0; i < qlen; i++) {
+ struct kvm_vbus_event *event = &kvm_vbus.ring[i];
+ size_t len = sizeof(*event);
+ struct ioq_ring_desc *desc = iter.desc;
+
+ BUG_ON(iter.desc->valid);
+
+ desc->cookie = (u64)event;
+ desc->ptr = (u64)__pa(event);
+ desc->len = len; /* total length */
+ desc->valid = 1;
+
+ /*
+ * This push operation will simultaneously advance the
+ * valid-tail index and increment our position in the queue
+ * by one.
+ */
+ ret = ioq_iter_push(&iter, 0);
+ BUG_ON(ret < 0);
+ }
+
+ kvm_vbus.eventq.notifier = &eventq_notifier;
+
+ /*
+ * And finally, ensure that we can receive notification
+ */
+ ioq_notify_enable(&kvm_vbus.eventq, 0);
+
+ return 0;
+}
+
+/* Invoked whenever the hypervisor ioq_signal()s our eventq */
+static void
+eventq_wakeup(struct ioq_notifier *notifier)
+{
+ struct ioq_iterator iter;
+ int ret;
+
+ /* We want to iterate on the head of the in-use index */
+ ret = ioq_iter_init(&kvm_vbus.eventq, &iter, ioq_idxtype_inuse, 0);
+ BUG_ON(ret < 0);
+
+ ret = ioq_iter_seek(&iter, ioq_seek_head, 0, 0);
+ BUG_ON(ret < 0);
+
+ /*
+ * The EOM is indicated by finding a packet that is still owned by
+ * the south side.
+ *
+ * FIXME: This in theory could run indefinitely if the host keeps
+ * feeding us events since there is nothing like a NAPI budget. We
+ * might need to address that
+ */
+ while (!iter.desc->sown) {
+ struct ioq_ring_desc *desc = iter.desc;
+ struct kvm_vbus_event *event;
+
+ event = (struct kvm_vbus_event *)desc->cookie;
+
+ switch (event->eventid) {
+ case KVM_VBUS_EVENT_DEVADD:
+ event_devadd(&event->data.add);
+ break;
+ case KVM_VBUS_EVENT_DEVDROP:
+ event_devdrop(&event->data.handle);
+ break;
+ case KVM_VBUS_EVENT_SHMSIGNAL:
+ event_shmsignal(&event->data.handle);
+ break;
+ case KVM_VBUS_EVENT_SHMCLOSE:
+ event_shmclose(&event->data.handle);
+ break;
+ default:
+ printk(KERN_WARNING "KVM_VBUS: Unexpected event %d\n",
+ event->eventid);
+ break;
+ };
+
+ memset(event, 0, sizeof(*event));
+
+ /* Advance the in-use head */
+ ret = ioq_iter_pop(&iter, 0);
+ BUG_ON(ret < 0);
+ }
+
+ /* And let the south side know that we changed the queue */
+ ioq_signal(&kvm_vbus.eventq, 0);
+}
+
+static struct ioq_notifier eventq_notifier = {
+ .signal = &eventq_wakeup,
+};
+
+/* Injected whenever the host issues an ioq_signal() on the eventq */
+irqreturn_t
+eventq_intr(int irq, void *dev)
+{
+ _shm_signal_wakeup(kvm_vbus.eventq.signal);
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * -------------------
+ */
+
+static int
+eventq_signal_inject(struct shm_signal *signal)
+{
+ u64 handle = 0; /* The eventq uses the special-case handle=0 */
+
+ kvm_vbus_hypercall(KVM_VBUS_OP_SHMSIGNAL, &handle, sizeof(handle));
+
+ return 0;
+}
+
+static void
+eventq_signal_release(struct shm_signal *signal)
+{
+ kfree(signal);
+}
+
+static struct shm_signal_ops eventq_signal_ops = {
+ .inject = eventq_signal_inject,
+ .release = eventq_signal_release,
+};
+
+/*
+ * -------------------
+ */
+
+static void
+eventq_ioq_release(struct ioq *ioq)
+{
+ /* released as part of the kvm_vbus object */
+}
+
+static struct ioq_ops eventq_ioq_ops = {
+ .release = eventq_ioq_release,
+};
+
+/*
+ * -------------------
+ */
+
+static void
+kvm_vbus_release(void)
+{
+ if (kvm_vbus.irq > 0) {
+ free_irq(kvm_vbus.irq, NULL);
+ destroy_kvm_dynirq(kvm_vbus.irq);
+ }
+
+ kfree(kvm_vbus.eventq.head_desc);
+ kfree(kvm_vbus.ring);
+}
+
+static int __init
+kvm_vbus_open(void)
+{
+ struct kvm_vbus_busopen params = {
+ .magic = KVM_VBUS_MAGIC,
+ .version = KVM_VBUS_VERSION,
+ .capabilities = 0,
+ };
+
+ return kvm_vbus_hypercall(KVM_VBUS_OP_BUSOPEN, &params, sizeof(params));
+}
+
+#define QLEN 1024
+
+static int __init
+kvm_vbus_register(void)
+{
+ struct kvm_vbus_busreg params = {
+ .count = 1,
+ .eventq = {
+ {
+ .irq = kvm_vbus.irq,
+ .count = QLEN,
+ .ring = (u64)__pa(kvm_vbus.eventq.head_desc),
+ .data = (u64)__pa(kvm_vbus.ring),
+ },
+ },
+ };
+
+ return kvm_vbus_hypercall(KVM_VBUS_OP_BUSREG, &params, sizeof(params));
+}
+
+static int __init
+_ioq_init(size_t ringsize, struct ioq *ioq, struct ioq_ops *ops)
+{
+ struct shm_signal *signal = NULL;
+ struct ioq_ring_head *head = NULL;
+ size_t len = IOQ_HEAD_DESC_SIZE(ringsize);
+
+ head = kzalloc(len, GFP_KERNEL | GFP_DMA);
+ if (!head)
+ return -ENOMEM;
+
+ signal = kzalloc(sizeof(*signal), GFP_KERNEL);
+ if (!signal) {
+ kfree(head);
+ return -ENOMEM;
+ }
+
+ head->magic = IOQ_RING_MAGIC;
+ head->ver = IOQ_RING_VER;
+ head->count = ringsize;
+
+ _signal_init(signal, &head->signal, &eventq_signal_ops);
+
+ ioq_init(ioq, ops, ioq_locality_north, head, signal, ringsize);
+
+ return 0;
+}
+
+int __init
+kvm_vbus_init(void)
+{
+ int ret;
+
+ memset(&kvm_vbus, 0, sizeof(kvm_vbus));
+
+ ret = kvm_para_has_feature(KVM_FEATURE_VBUS);
+ if (!ret)
+ return -ENOENT;
+
+ ret = kvm_vbus_open();
+ if (ret < 0) {
+ printk(KERN_ERR "KVM_VBUS: Could not register with host: %d\n",
+ ret);
+ goto out_fail;
+ }
+
+ spin_lock_init(&kvm_vbus.lock);
+
+ /*
+ * Allocate an IOQ to use for host-2-guest event notification
+ */
+ ret = _ioq_init(QLEN, &kvm_vbus.eventq, &eventq_ioq_ops);
+ if (ret < 0) {
+ printk(KERN_ERR "KVM_VBUS: Cound not init eventq\n");
+ goto out_fail;
+ }
+
+ ret = eventq_init(QLEN);
+ if (ret < 0) {
+ printk(KERN_ERR "KVM_VBUS: Cound not setup ring\n");
+ goto out_fail;
+ }
+
+ /*
+ * Dynamically assign a free IRQ to this resource
+ */
+ kvm_vbus.irq = create_kvm_dynirq(0);
+ if (kvm_vbus.irq < 0) {
+ printk(KERN_ERR "KVM_VBUS: Failed to create IRQ\n");
+ goto out_fail;
+ }
+
+ ret = request_irq(kvm_vbus.irq, eventq_intr, 0, "vbus", NULL);
+ if (ret < 0) {
+ printk(KERN_ERR "KVM_VBUS: Failed to register IRQ %d\n: %d",
+ kvm_vbus.irq, ret);
+ goto out_fail;
+ }
+
+ /*
+ * Finally register our queue on the host to start receiving events
+ */
+ ret = kvm_vbus_register();
+ if (ret < 0) {
+ printk(KERN_ERR "KVM_VBUS: Could not register with host: %d\n",
+ ret);
+ goto out_fail;
+ }
+
+ return 0;
+
+ out_fail:
+ kvm_vbus_release();
+
+ return ret;
+
+}
+
+static void __exit
+kvm_vbus_exit(void)
+{
+ kvm_vbus_release();
+}
+
+module_init(kvm_vbus_init);
+module_exit(kvm_vbus_exit);
+


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