zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/drivers/lguest/lguest_device.c b/ap/os/linux/linux-3.4.x/drivers/lguest/lguest_device.c
new file mode 100644
index 0000000..9e8388e
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/drivers/lguest/lguest_device.c
@@ -0,0 +1,531 @@
+/*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.
+:*/
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/lguest_launcher.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/interrupt.h>
+#include <linux/virtio_ring.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <asm/io.h>
+#include <asm/paravirt.h>
+#include <asm/lguest_hcall.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.
+ */
+static inline void *lguest_map(unsigned long phys_addr, unsigned long pages)
+{
+ return (__force void *)ioremap_cache(phys_addr, PAGE_SIZE*pages);
+}
+
+static inline void lguest_unmap(void *addr)
+{
+ 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.
+ */
+struct lguest_device {
+ struct virtio_device vdev;
+
+ /* The entry in the lguest_devices page for this device. */
+ struct lguest_device_desc *desc;
+};
+
+/*
+ * 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.
+ */
+#define to_lgdev(vd) container_of(vd, struct lguest_device, vdev)
+
+/*D:130
+ * Device configurations
+ *
+ * The configuration information for a device consists of one or more
+ * virtqueues, a feature bitmap, and some configuration bytes. The
+ * configuration bytes don't really matter to us: the Launcher sets them up, and
+ * the driver will look at them during setup.
+ *
+ * A convenient routine to return the device's virtqueue config array:
+ * immediately after the descriptor.
+ */
+static struct lguest_vqconfig *lg_vq(const struct lguest_device_desc *desc)
+{
+ return (void *)(desc + 1);
+}
+
+/* The features come immediately after the virtqueues. */
+static u8 *lg_features(const struct lguest_device_desc *desc)
+{
+ return (void *)(lg_vq(desc) + desc->num_vq);
+}
+
+/* The config space comes after the two feature bitmasks. */
+static u8 *lg_config(const struct lguest_device_desc *desc)
+{
+ return lg_features(desc) + desc->feature_len * 2;
+}
+
+/* The total size of the config page used by this device (incl. desc) */
+static unsigned desc_size(const struct lguest_device_desc *desc)
+{
+ return sizeof(*desc)
+ + desc->num_vq * sizeof(struct lguest_vqconfig)
+ + desc->feature_len * 2
+ + desc->config_len;
+}
+
+/* This gets the device's feature bits. */
+static u32 lg_get_features(struct virtio_device *vdev)
+{
+ unsigned int i;
+ u32 features = 0;
+ struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
+ u8 *in_features = lg_features(desc);
+
+ /* We do this the slow but generic way. */
+ for (i = 0; i < min(desc->feature_len * 8, 32); i++)
+ if (in_features[i / 8] & (1 << (i % 8)))
+ features |= (1 << i);
+
+ return features;
+}
+
+/*
+ * To notify on reset or feature finalization, we (ab)use the NOTIFY
+ * hypercall, with the descriptor address of the device.
+ */
+static void status_notify(struct virtio_device *vdev)
+{
+ unsigned long offset = (void *)to_lgdev(vdev)->desc - lguest_devices;
+
+ hcall(LHCALL_NOTIFY, (max_pfn << PAGE_SHIFT) + offset, 0, 0, 0);
+}
+
+/*
+ * 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;
+ struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
+ /* Second half of bitmap is features we accept. */
+ u8 *out_features = lg_features(desc) + desc->feature_len;
+
+ /* 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.
+ */
+ memset(out_features, 0, desc->feature_len);
+ bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
+ for (i = 0; i < bits; i++) {
+ if (test_bit(i, vdev->features))
+ out_features[i / 8] |= (1 << (i % 8));
+ }
+
+ /* Tell Host we've finished with this device's feature negotiation */
+ status_notify(vdev);
+}
+
+/* Once they've found a field, getting a copy of it is easy. */
+static void lg_get(struct virtio_device *vdev, unsigned int offset,
+ void *buf, unsigned len)
+{
+ struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
+
+ /* Check they didn't ask for more than the length of the config! */
+ BUG_ON(offset + len > desc->config_len);
+ memcpy(buf, lg_config(desc) + offset, len);
+}
+
+/* Setting the contents is also trivial. */
+static void lg_set(struct virtio_device *vdev, unsigned int offset,
+ const void *buf, unsigned len)
+{
+ struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
+
+ /* Check they didn't ask for more than the length of the config! */
+ BUG_ON(offset + len > desc->config_len);
+ 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.
+ */
+static u8 lg_get_status(struct virtio_device *vdev)
+{
+ return to_lgdev(vdev)->desc->status;
+}
+
+static void lg_set_status(struct virtio_device *vdev, u8 status)
+{
+ BUG_ON(!status);
+ to_lgdev(vdev)->desc->status = status;
+
+ /* Tell Host immediately if we failed. */
+ if (status & VIRTIO_CONFIG_S_FAILED)
+ status_notify(vdev);
+}
+
+static void lg_reset(struct virtio_device *vdev)
+{
+ /* 0 status means "reset" */
+ to_lgdev(vdev)->desc->status = 0;
+ status_notify(vdev);
+}
+
+/*
+ * Virtqueues
+ *
+ * The other piece of infrastructure virtio needs is a "virtqueue": a way of
+ * the Guest device registering buffers for the other side to read from or
+ * write into (ie. send and receive buffers). Each device can have multiple
+ * virtqueues: for example the console driver uses one queue for sending and
+ * another for receiving.
+ *
+ * Fortunately for us, a very fast shared-memory-plus-descriptors virtqueue
+ * already exists in virtio_ring.c. We just need to connect it up.
+ *
+ * We start with the information we need to keep about each virtqueue.
+ */
+
+/*D:140 This is the information we remember about each virtqueue. */
+struct lguest_vq_info {
+ /* A copy of the information contained in the device config. */
+ struct lguest_vqconfig config;
+
+ /* The address where we mapped the virtio ring, so we can unmap it. */
+ void *pages;
+};
+
+/*
+ * 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.
+ */
+static void lg_notify(struct virtqueue *vq)
+{
+ /*
+ * We store our virtqueue information in the "priv" pointer of the
+ * virtqueue structure.
+ */
+ struct lguest_vq_info *lvq = vq->priv;
+
+ hcall(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT, 0, 0, 0);
+}
+
+/* An extern declaration inside a C file is bad form. Don't do it. */
+extern int lguest_setup_irq(unsigned int irq);
+
+/*
+ * 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
+ * representation of a virtqueue in the configuration space, but it seems that
+ * 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.
+ */
+static struct virtqueue *lg_find_vq(struct virtio_device *vdev,
+ unsigned index,
+ void (*callback)(struct virtqueue *vq),
+ const char *name)
+{
+ struct lguest_device *ldev = to_lgdev(vdev);
+ struct lguest_vq_info *lvq;
+ struct virtqueue *vq;
+ int err;
+
+ /* We must have this many virtqueues. */
+ if (index >= ldev->desc->num_vq)
+ return ERR_PTR(-ENOENT);
+
+ lvq = kmalloc(sizeof(*lvq), GFP_KERNEL);
+ if (!lvq)
+ return ERR_PTR(-ENOMEM);
+
+ /*
+ * 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.
+ */
+ memcpy(&lvq->config, lg_vq(ldev->desc)+index, sizeof(lvq->config));
+
+ printk("Mapping virtqueue %i addr %lx\n", index,
+ (unsigned long)lvq->config.pfn << PAGE_SHIFT);
+ /* Figure out how many pages the ring will take, and map that memory */
+ lvq->pages = lguest_map((unsigned long)lvq->config.pfn << PAGE_SHIFT,
+ DIV_ROUND_UP(vring_size(lvq->config.num,
+ LGUEST_VRING_ALIGN),
+ PAGE_SIZE));
+ if (!lvq->pages) {
+ err = -ENOMEM;
+ 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. Note that we set weak_barriers
+ * to 'true': the host just a(nother) SMP CPU, so we only need inter-cpu
+ * barriers.
+ */
+ vq = vring_new_virtqueue(lvq->config.num, LGUEST_VRING_ALIGN, vdev,
+ true, lvq->pages, lg_notify, callback, name);
+ if (!vq) {
+ err = -ENOMEM;
+ goto unmap;
+ }
+
+ /* Make sure the interrupt is allocated. */
+ err = lguest_setup_irq(lvq->config.irq);
+ if (err)
+ goto destroy_vring;
+
+ /*
+ * 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.
+ */
+ err = request_irq(lvq->config.irq, vring_interrupt, IRQF_SHARED,
+ dev_name(&vdev->dev), vq);
+ if (err)
+ goto free_desc;
+
+ /*
+ * Last of all we hook up our 'struct lguest_vq_info" to the
+ * virtqueue's priv pointer.
+ */
+ vq->priv = lvq;
+ return vq;
+
+free_desc:
+ irq_free_desc(lvq->config.irq);
+destroy_vring:
+ vring_del_virtqueue(vq);
+unmap:
+ lguest_unmap(lvq->pages);
+free_lvq:
+ kfree(lvq);
+ return ERR_PTR(err);
+}
+/*:*/
+
+/* Cleaning up a virtqueue is easy */
+static void lg_del_vq(struct virtqueue *vq)
+{
+ struct lguest_vq_info *lvq = vq->priv;
+
+ /* Release the interrupt */
+ free_irq(lvq->config.irq, vq);
+ /* Tell virtio_ring.c to free the virtqueue. */
+ vring_del_virtqueue(vq);
+ /* Unmap the pages containing the ring. */
+ lguest_unmap(lvq->pages);
+ /* Free our own queue information. */
+ kfree(lvq);
+}
+
+static void lg_del_vqs(struct virtio_device *vdev)
+{
+ struct virtqueue *vq, *n;
+
+ list_for_each_entry_safe(vq, n, &vdev->vqs, list)
+ lg_del_vq(vq);
+}
+
+static int lg_find_vqs(struct virtio_device *vdev, unsigned nvqs,
+ struct virtqueue *vqs[],
+ vq_callback_t *callbacks[],
+ const char *names[])
+{
+ struct lguest_device *ldev = to_lgdev(vdev);
+ int i;
+
+ /* We must have this many virtqueues. */
+ if (nvqs > ldev->desc->num_vq)
+ return -ENOENT;
+
+ for (i = 0; i < nvqs; ++i) {
+ vqs[i] = lg_find_vq(vdev, i, callbacks[i], names[i]);
+ if (IS_ERR(vqs[i]))
+ goto error;
+ }
+ return 0;
+
+error:
+ lg_del_vqs(vdev);
+ return PTR_ERR(vqs[i]);
+}
+
+static const char *lg_bus_name(struct virtio_device *vdev)
+{
+ return "";
+}
+
+/* The ops structure which hooks everything together. */
+static struct virtio_config_ops lguest_config_ops = {
+ .get_features = lg_get_features,
+ .finalize_features = lg_finalize_features,
+ .get = lg_get,
+ .set = lg_set,
+ .get_status = lg_get_status,
+ .set_status = lg_set_status,
+ .reset = lg_reset,
+ .find_vqs = lg_find_vqs,
+ .del_vqs = lg_del_vqs,
+ .bus_name = lg_bus_name,
+};
+
+/*
+ * 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.
+ * 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.
+ *
+ * As Andrew Tridgell says, "Untested code is buggy code".
+ *
+ * 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.
+ */
+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 counts on it. */
+ ldev = kzalloc(sizeof(*ldev), GFP_KERNEL);
+ if (!ldev) {
+ printk(KERN_EMERG "Cannot allocate lguest dev %u type %u\n",
+ offset, d->type);
+ return;
+ }
+
+ /* This devices' parent is the lguest/ dir. */
+ ldev->vdev.dev.parent = lguest_root;
+ /*
+ * 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.
+ */
+ 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
+ * virtio_device and calls device_register(). This makes the bus
+ * 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);
+ kfree(ldev);
+ }
+}
+
+/*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;
+ struct lguest_device_desc *d;
+
+ /* We start at the page beginning, and skip over each entry. */
+ for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
+ d = lguest_devices + i;
+
+ /* Once we hit a zero, stop. */
+ if (d->type == 0)
+ break;
+
+ printk("Device at %i has size %u\n", i, desc_size(d));
+ add_lguest_device(d, i);
+ }
+}
+
+/*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.
+ *
+ * So we can access the "struct lguest_device_desc"s easily, we map that memory
+ * and store the pointer in the global "lguest_devices". Then we register a
+ * root device from which all our devices will hang (this seems to be the
+ * correct sysfs incantation).
+ *
+ * Finally we call scan_devices() which adds all the devices found in the
+ * lguest_devices page.
+ */
+static int __init lguest_devices_init(void)
+{
+ if (strcmp(pv_info.name, "lguest") != 0)
+ return 0;
+
+ lguest_root = root_device_register("lguest");
+ if (IS_ERR(lguest_root))
+ panic("Could not register lguest root");
+
+ /* Devices are in a single page above top of "normal" mem */
+ lguest_devices = lguest_map(max_pfn<<PAGE_SHIFT, 1);
+
+ scan_devices();
+ return 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
+ * 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?".
+ */