-/*P:050 Lguest guests use a very simple method to describe devices. It's a
+/*P:050
+ * Lguest guests use a very simple method to describe devices. It's a
* series of device descriptors contained just above the top of normal Guest
* memory.
*
* We use the standard "virtio" device infrastructure, which provides us with a
* console, a network and a block driver. Each one expects some configuration
- * information and a "virtqueue" or two to send and receive data. :*/
+ * information and a "virtqueue" or two to send and receive data.
+:*/
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/lguest_launcher.h>
/* The pointer to our (page) of device descriptions. */
static void *lguest_devices;
-/* For Guests, device memory can be used as normal memory, so we cast away the
- * __iomem to quieten sparse. */
+/*
+ * For Guests, device memory can be used as normal memory, so we cast away the
+ * __iomem to quieten sparse.
+ */
static inline void *lguest_map(unsigned long phys_addr, unsigned long pages)
{
return (__force void *)ioremap_cache(phys_addr, PAGE_SIZE*pages);
iounmap((__force void __iomem *)addr);
}
-/*D:100 Each lguest device is just a virtio device plus a pointer to its entry
- * in the lguest_devices page. */
+/*D:100
+ * Each lguest device is just a virtio device plus a pointer to its entry
+ * in the lguest_devices page.
+ */
struct lguest_device {
struct virtio_device vdev;
struct lguest_device_desc *desc;
};
-/* Since the virtio infrastructure hands us a pointer to the virtio_device all
+/*
+ * Since the virtio infrastructure hands us a pointer to the virtio_device all
* the time, it helps to have a curt macro to get a pointer to the struct
- * lguest_device it's enclosed in. */
+ * lguest_device it's enclosed in.
+ */
#define to_lgdev(vd) container_of(vd, struct lguest_device, vdev)
/*D:130
* the driver will look at them during setup.
*
* A convenient routine to return the device's virtqueue config array:
- * immediately after the descriptor. */
+ * immediately after the descriptor.
+ */
static struct lguest_vqconfig *lg_vq(const struct lguest_device_desc *desc)
{
return (void *)(desc + 1);
return features;
}
-/* The virtio core takes the features the Host offers, and copies the
- * ones supported by the driver into the vdev->features array. Once
- * that's all sorted out, this routine is called so we can tell the
- * Host which features we understand and accept. */
+/*
+ * The virtio core takes the features the Host offers, and copies the ones
+ * supported by the driver into the vdev->features array. Once that's all
+ * sorted out, this routine is called so we can tell the Host which features we
+ * understand and accept.
+ */
static void lg_finalize_features(struct virtio_device *vdev)
{
unsigned int i, bits;
/* Give virtio_ring a chance to accept features. */
vring_transport_features(vdev);
- /* The vdev->feature array is a Linux bitmask: this isn't the
- * same as a the simple array of bits used by lguest devices
- * for features. So we do this slow, manual conversion which is
- * completely general. */
+ /*
+ * The vdev->feature array is a Linux bitmask: this isn't the same as a
+ * the simple array of bits used by lguest devices for features. So we
+ * do this slow, manual conversion which is completely general.
+ */
memset(out_features, 0, desc->feature_len);
bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
for (i = 0; i < bits; i++) {
memcpy(lg_config(desc) + offset, buf, len);
}
-/* The operations to get and set the status word just access the status field
- * of the device descriptor. */
+/*
+ * The operations to get and set the status word just access the status field
+ * of the device descriptor.
+ */
static u8 lg_get_status(struct virtio_device *vdev)
{
return to_lgdev(vdev)->desc->status;
}
-/* To notify on status updates, we (ab)use the NOTIFY hypercall, with the
- * descriptor address of the device. A zero status means "reset". */
+/*
+ * To notify on status updates, we (ab)use the NOTIFY hypercall, with the
+ * descriptor address of the device. A zero status means "reset".
+ */
static void set_status(struct virtio_device *vdev, u8 status)
{
unsigned long offset = (void *)to_lgdev(vdev)->desc - lguest_devices;
*/
/*D:140 This is the information we remember about each virtqueue. */
-struct lguest_vq_info
-{
+struct lguest_vq_info {
/* A copy of the information contained in the device config. */
struct lguest_vqconfig config;
void *pages;
};
-/* When the virtio_ring code wants to prod the Host, it calls us here and we
+/*
+ * When the virtio_ring code wants to prod the Host, it calls us here and we
* make a hypercall. We hand the physical address of the virtqueue so the Host
- * knows which virtqueue we're talking about. */
+ * knows which virtqueue we're talking about.
+ */
static void lg_notify(struct virtqueue *vq)
{
- /* We store our virtqueue information in the "priv" pointer of the
- * virtqueue structure. */
+ /*
+ * We store our virtqueue information in the "priv" pointer of the
+ * virtqueue structure.
+ */
struct lguest_vq_info *lvq = vq->priv;
kvm_hypercall1(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT);
/* An extern declaration inside a C file is bad form. Don't do it. */
extern void lguest_setup_irq(unsigned int irq);
-/* This routine finds the first virtqueue described in the configuration of
+/*
+ * This routine finds the Nth virtqueue described in the configuration of
* this device and sets it up.
*
* This is kind of an ugly duckling. It'd be nicer to have a standard
* everyone wants to do it differently. The KVM coders want the Guest to
* allocate its own pages and tell the Host where they are, but for lguest it's
* simpler for the Host to simply tell us where the pages are.
- *
- * So we provide drivers with a "find the Nth virtqueue and set it up"
- * function. */
+ */
static struct virtqueue *lg_find_vq(struct virtio_device *vdev,
unsigned index,
void (*callback)(struct virtqueue *vq),
if (!lvq)
return ERR_PTR(-ENOMEM);
- /* Make a copy of the "struct lguest_vqconfig" entry, which sits after
+ /*
+ * Make a copy of the "struct lguest_vqconfig" entry, which sits after
* the descriptor. We need a copy because the config space might not
- * be aligned correctly. */
+ * be aligned correctly.
+ */
memcpy(&lvq->config, lg_vq(ldev->desc)+index, sizeof(lvq->config));
printk("Mapping virtqueue %i addr %lx\n", index,
goto free_lvq;
}
- /* OK, tell virtio_ring.c to set up a virtqueue now we know its size
- * and we've got a pointer to its pages. */
+ /*
+ * OK, tell virtio_ring.c to set up a virtqueue now we know its size
+ * and we've got a pointer to its pages.
+ */
vq = vring_new_virtqueue(lvq->config.num, LGUEST_VRING_ALIGN,
vdev, lvq->pages, lg_notify, callback, name);
if (!vq) {
/* Make sure the interrupt is allocated. */
lguest_setup_irq(lvq->config.irq);
- /* Tell the interrupt for this virtqueue to go to the virtio_ring
- * interrupt handler. */
- /* FIXME: We used to have a flag for the Host to tell us we could use
+ /*
+ * Tell the interrupt for this virtqueue to go to the virtio_ring
+ * interrupt handler.
+ *
+ * FIXME: We used to have a flag for the Host to tell us we could use
* the interrupt as a source of randomness: it'd be nice to have that
- * back.. */
+ * back.
+ */
err = request_irq(lvq->config.irq, vring_interrupt, IRQF_SHARED,
dev_name(&vdev->dev), vq);
if (err)
goto destroy_vring;
- /* Last of all we hook up our 'struct lguest_vq_info" to the
- * virtqueue's priv pointer. */
+ /*
+ * Last of all we hook up our 'struct lguest_vq_info" to the
+ * virtqueue's priv pointer.
+ */
vq->priv = lvq;
return vq;
.del_vqs = lg_del_vqs,
};
-/* The root device for the lguest virtio devices. This makes them appear as
- * /sys/devices/lguest/0,1,2 not /sys/devices/0,1,2. */
+/*
+ * The root device for the lguest virtio devices. This makes them appear as
+ * /sys/devices/lguest/0,1,2 not /sys/devices/0,1,2.
+ */
static struct device *lguest_root;
-/*D:120 This is the core of the lguest bus: actually adding a new device.
+/*D:120
+ * This is the core of the lguest bus: actually adding a new device.
* It's a separate function because it's neater that way, and because an
* earlier version of the code supported hotplug and unplug. They were removed
* early on because they were never used.
*
* It's worth reading this carefully: we start with a pointer to the new device
* descriptor in the "lguest_devices" page, and the offset into the device
- * descriptor page so we can uniquely identify it if things go badly wrong. */
+ * descriptor page so we can uniquely identify it if things go badly wrong.
+ */
static void add_lguest_device(struct lguest_device_desc *d,
unsigned int offset)
{
struct lguest_device *ldev;
- /* Start with zeroed memory; Linux's device layer seems to count on
- * it. */
+ /* Start with zeroed memory; Linux's device layer counts on it. */
ldev = kzalloc(sizeof(*ldev), GFP_KERNEL);
if (!ldev) {
printk(KERN_EMERG "Cannot allocate lguest dev %u type %u\n",
/* This devices' parent is the lguest/ dir. */
ldev->vdev.dev.parent = lguest_root;
- /* We have a unique device index thanks to the dev_index counter. */
+ /*
+ * The device type comes straight from the descriptor. There's also a
+ * device vendor field in the virtio_device struct, which we leave as
+ * 0.
+ */
ldev->vdev.id.device = d->type;
- /* We have a simple set of routines for querying the device's
- * configuration information and setting its status. */
+ /*
+ * We have a simple set of routines for querying the device's
+ * configuration information and setting its status.
+ */
ldev->vdev.config = &lguest_config_ops;
/* And we remember the device's descriptor for lguest_config_ops. */
ldev->desc = d;
- /* register_virtio_device() sets up the generic fields for the struct
+ /*
+ * register_virtio_device() sets up the generic fields for the struct
* virtio_device and calls device_register(). This makes the bus
- * infrastructure look for a matching driver. */
+ * infrastructure look for a matching driver.
+ */
if (register_virtio_device(&ldev->vdev) != 0) {
printk(KERN_ERR "Failed to register lguest dev %u type %u\n",
offset, d->type);
}
}
-/*D:110 scan_devices() simply iterates through the device page. The type 0 is
- * reserved to mean "end of devices". */
+/*D:110
+ * scan_devices() simply iterates through the device page. The type 0 is
+ * reserved to mean "end of devices".
+ */
static void scan_devices(void)
{
unsigned int i;
}
}
-/*D:105 Fairly early in boot, lguest_devices_init() is called to set up the
+/*D:105
+ * Fairly early in boot, lguest_devices_init() is called to set up the
* lguest device infrastructure. We check that we are a Guest by checking
* pv_info.name: there are other ways of checking, but this seems most
* obvious to me.
* correct sysfs incantation).
*
* Finally we call scan_devices() which adds all the devices found in the
- * lguest_devices page. */
+ * lguest_devices page.
+ */
static int __init lguest_devices_init(void)
{
if (strcmp(pv_info.name, "lguest") != 0)
/* We do this after core stuff, but before the drivers. */
postcore_initcall(lguest_devices_init);
-/*D:150 At this point in the journey we used to now wade through the lguest
+/*D:150
+ * At this point in the journey we used to now wade through the lguest
* devices themselves: net, block and console. Since they're all now virtio
* devices rather than lguest-specific, I've decided to ignore them. Mostly,
* they're kind of boring. But this does mean you'll never experience the
* thrill of reading the forbidden love scene buried deep in the block driver.
*
* "make Launcher" beckons, where we answer questions like "Where do Guests
- * come from?", and "What do you do when someone asks for optimization?". */
+ * come from?", and "What do you do when someone asks for optimization?".
+ */
git.openpandora.org / pandora-kernel.git / blobdiff