07ad157f6e
lguest is a simple hypervisor for Linux on Linux. Unlike kvm it doesn't need VT/SVM hardware. Unlike Xen it's simply "modprobe and go". Unlike both, it's 5000 lines and self-contained. Performance is ok, but not great (-30% on kernel compile). But given its hackability, I expect this to improve, along with the paravirt_ops code which it supplies a complete example for. There's also a 64-bit version being worked on and other craziness. But most of all, lguest is awesome fun! Too much of the kernel is a big ball of hair. lguest is simple enough to dive into and hack, plus has some warts which scream "fork me!". This patch: This is the code and headers required to make an i386 kernel an lguest guest. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
148 lines
4.1 KiB
C
148 lines
4.1 KiB
C
#include <linux/init.h>
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#include <linux/bootmem.h>
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#include <linux/lguest_bus.h>
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#include <asm/io.h>
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static ssize_t type_show(struct device *_dev,
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struct device_attribute *attr, char *buf)
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{
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struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
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return sprintf(buf, "%hu", lguest_devices[dev->index].type);
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}
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static ssize_t features_show(struct device *_dev,
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struct device_attribute *attr, char *buf)
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{
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struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
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return sprintf(buf, "%hx", lguest_devices[dev->index].features);
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}
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static ssize_t pfn_show(struct device *_dev,
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struct device_attribute *attr, char *buf)
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{
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struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
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return sprintf(buf, "%u", lguest_devices[dev->index].pfn);
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}
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static ssize_t status_show(struct device *_dev,
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struct device_attribute *attr, char *buf)
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{
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struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
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return sprintf(buf, "%hx", lguest_devices[dev->index].status);
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}
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static ssize_t status_store(struct device *_dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
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if (sscanf(buf, "%hi", &lguest_devices[dev->index].status) != 1)
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return -EINVAL;
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return count;
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}
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static struct device_attribute lguest_dev_attrs[] = {
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__ATTR_RO(type),
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__ATTR_RO(features),
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__ATTR_RO(pfn),
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__ATTR(status, 0644, status_show, status_store),
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__ATTR_NULL
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};
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static int lguest_dev_match(struct device *_dev, struct device_driver *_drv)
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{
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struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
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struct lguest_driver *drv = container_of(_drv,struct lguest_driver,drv);
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return (drv->device_type == lguest_devices[dev->index].type);
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}
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struct lguest_bus {
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struct bus_type bus;
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struct device dev;
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};
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static struct lguest_bus lguest_bus = {
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.bus = {
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.name = "lguest",
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.match = lguest_dev_match,
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.dev_attrs = lguest_dev_attrs,
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},
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.dev = {
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.parent = NULL,
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.bus_id = "lguest",
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}
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};
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static int lguest_dev_probe(struct device *_dev)
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{
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int ret;
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struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
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struct lguest_driver *drv = container_of(dev->dev.driver,
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struct lguest_driver, drv);
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lguest_devices[dev->index].status |= LGUEST_DEVICE_S_DRIVER;
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ret = drv->probe(dev);
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if (ret == 0)
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lguest_devices[dev->index].status |= LGUEST_DEVICE_S_DRIVER_OK;
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return ret;
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}
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int register_lguest_driver(struct lguest_driver *drv)
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{
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if (!lguest_devices)
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return 0;
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drv->drv.bus = &lguest_bus.bus;
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drv->drv.name = drv->name;
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drv->drv.owner = drv->owner;
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drv->drv.probe = lguest_dev_probe;
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return driver_register(&drv->drv);
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}
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EXPORT_SYMBOL_GPL(register_lguest_driver);
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static void add_lguest_device(unsigned int index)
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{
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struct lguest_device *new;
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lguest_devices[index].status |= LGUEST_DEVICE_S_ACKNOWLEDGE;
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new = kmalloc(sizeof(struct lguest_device), GFP_KERNEL);
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if (!new) {
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printk(KERN_EMERG "Cannot allocate lguest device %u\n", index);
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lguest_devices[index].status |= LGUEST_DEVICE_S_FAILED;
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return;
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}
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new->index = index;
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new->private = NULL;
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memset(&new->dev, 0, sizeof(new->dev));
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new->dev.parent = &lguest_bus.dev;
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new->dev.bus = &lguest_bus.bus;
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sprintf(new->dev.bus_id, "%u", index);
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if (device_register(&new->dev) != 0) {
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printk(KERN_EMERG "Cannot register lguest device %u\n", index);
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lguest_devices[index].status |= LGUEST_DEVICE_S_FAILED;
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kfree(new);
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}
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}
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static void scan_devices(void)
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{
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unsigned int i;
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for (i = 0; i < LGUEST_MAX_DEVICES; i++)
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if (lguest_devices[i].type)
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add_lguest_device(i);
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}
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static int __init lguest_bus_init(void)
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{
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if (strcmp(paravirt_ops.name, "lguest") != 0)
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return 0;
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/* Devices are in page above top of "normal" mem. */
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lguest_devices = lguest_map(max_pfn<<PAGE_SHIFT, 1);
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if (bus_register(&lguest_bus.bus) != 0
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|| device_register(&lguest_bus.dev) != 0)
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panic("lguest bus registration failed");
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scan_devices();
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return 0;
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}
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postcore_initcall(lguest_bus_init);
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