#include <zlib.h>
#include <assert.h>
#include <sched.h>
+#include <limits.h>
+#include <stddef.h>
#include "linux/lguest_launcher.h"
#include "linux/virtio_config.h"
#include "linux/virtio_net.h"
/* The maximum guest physical address allowed, and maximum possible. */
static unsigned long guest_limit, guest_max;
+/* a per-cpu variable indicating whose vcpu is currently running */
+static unsigned int __thread cpu_id;
+
/* This is our list of devices. */
struct device_list
{
/* The descriptor page for the devices. */
u8 *descpage;
- /* The tail of the last descriptor. */
- unsigned int desc_used;
-
/* A single linked list of devices. */
struct device *dev;
- /* ... And an end pointer so we can easily append new devices */
- struct device **lastdev;
+ /* And a pointer to the last device for easy append and also for
+ * configuration appending. */
+ struct device *lastdev;
};
/* The list of Guest devices, based on command line arguments. */
void (*handle_output)(int fd, struct virtqueue *me);
};
+/* Remember the arguments to the program so we can "reboot" */
+static char **main_args;
+
/* Since guest is UP and we don't run at the same time, we don't need barriers.
* But I include them in the code in case others copy it. */
#define wmb()
#define cpu_to_le64(v64) (v64)
#define le16_to_cpu(v16) (v16)
#define le32_to_cpu(v32) (v32)
-#define le64_to_cpu(v32) (v64)
+#define le64_to_cpu(v64) (v64)
+
+/* The device virtqueue descriptors are followed by feature bitmasks. */
+static u8 *get_feature_bits(struct device *dev)
+{
+ return (u8 *)(dev->desc + 1)
+ + dev->desc->num_vq * sizeof(struct lguest_vqconfig);
+}
/*L:100 The Launcher code itself takes us out into userspace, that scary place
* where pointers run wild and free! Unfortunately, like most userspace
unsigned int i, len = 0;
for (i = 0; args[i]; i++) {
+ if (i) {
+ strcat(dst+len, " ");
+ len++;
+ }
strcpy(dst+len, args[i]);
- strcat(dst+len, " ");
- len += strlen(args[i]) + 1;
+ len += strlen(args[i]);
}
/* In case it's empty. */
dst[len] = '\0';
else
FD_CLR(-fd - 1, &devices.infds);
} else /* Send LHREQ_BREAK command. */
- write(lguest_fd, args, sizeof(args));
+ pwrite(lguest_fd, args, sizeof(args), cpu_id);
}
}
write(waker_fd, &vq->dev->fd, sizeof(vq->dev->fd));
}
+/* Resetting a device is fairly easy. */
+static void reset_device(struct device *dev)
+{
+ struct virtqueue *vq;
+
+ verbose("Resetting device %s\n", dev->name);
+ /* Clear the status. */
+ dev->desc->status = 0;
+
+ /* Clear any features they've acked. */
+ memset(get_feature_bits(dev) + dev->desc->feature_len, 0,
+ dev->desc->feature_len);
+
+ /* Zero out the virtqueues. */
+ for (vq = dev->vq; vq; vq = vq->next) {
+ memset(vq->vring.desc, 0,
+ vring_size(vq->config.num, getpagesize()));
+ vq->last_avail_idx = 0;
+ }
+}
+
/* This is the generic routine we call when the Guest uses LHCALL_NOTIFY. */
static void handle_output(int fd, unsigned long addr)
{
struct device *i;
struct virtqueue *vq;
- /* Check each virtqueue. */
+ /* Check each device and virtqueue. */
for (i = devices.dev; i; i = i->next) {
+ /* Notifications to device descriptors reset the device. */
+ if (from_guest_phys(addr) == i->desc) {
+ reset_device(i);
+ return;
+ }
+
+ /* Notifications to virtqueues mean output has occurred. */
for (vq = i->vq; vq; vq = vq->next) {
- if (vq->config.pfn == addr/getpagesize()
- && vq->handle_output) {
- verbose("Output to %s\n", vq->dev->name);
- vq->handle_output(fd, vq);
+ if (vq->config.pfn != addr/getpagesize())
+ continue;
+
+ /* Guest should acknowledge (and set features!) before
+ * using the device. */
+ if (i->desc->status == 0) {
+ warnx("%s gave early output", i->name);
return;
}
+
+ if (strcmp(vq->dev->name, "console") != 0)
+ verbose("Output to %s\n", vq->dev->name);
+ if (vq->handle_output)
+ vq->handle_output(fd, vq);
+ return;
}
}
*
* All devices need a descriptor so the Guest knows it exists, and a "struct
* device" so the Launcher can keep track of it. We have common helper
- * routines to allocate them.
- *
- * This routine allocates a new "struct lguest_device_desc" from descriptor
- * table just above the Guest's normal memory. It returns a pointer to that
- * descriptor. */
-static struct lguest_device_desc *new_dev_desc(u16 type)
-{
- struct lguest_device_desc *d;
-
- /* We only have one page for all the descriptors. */
- if (devices.desc_used + sizeof(*d) > getpagesize())
- errx(1, "Too many devices");
+ * routines to allocate and manage them. */
- /* We don't need to set config_len or status: page is 0 already. */
- d = (void *)devices.descpage + devices.desc_used;
- d->type = type;
- devices.desc_used += sizeof(*d);
-
- return d;
+/* The layout of the device page is a "struct lguest_device_desc" followed by a
+ * number of virtqueue descriptors, then two sets of feature bits, then an
+ * array of configuration bytes. This routine returns the configuration
+ * pointer. */
+static u8 *device_config(const struct device *dev)
+{
+ return (void *)(dev->desc + 1)
+ + dev->desc->num_vq * sizeof(struct lguest_vqconfig)
+ + dev->desc->feature_len * 2;
}
-/* Each device descriptor is followed by some configuration information.
- * Each configuration field looks like: u8 type, u8 len, [... len bytes...].
- *
- * This routine adds a new field to an existing device's descriptor. It only
- * works for the last device, but that's OK because that's how we use it. */
-static void add_desc_field(struct device *dev, u8 type, u8 len, const void *c)
+/* This routine allocates a new "struct lguest_device_desc" from descriptor
+ * table page just above the Guest's normal memory. It returns a pointer to
+ * that descriptor. */
+static struct lguest_device_desc *new_dev_desc(u16 type)
{
- /* This is the last descriptor, right? */
- assert(devices.descpage + devices.desc_used
- == (u8 *)(dev->desc + 1) + dev->desc->config_len);
+ struct lguest_device_desc d = { .type = type };
+ void *p;
- /* We only have one page of device descriptions. */
- if (devices.desc_used + 2 + len > getpagesize())
- errx(1, "Too many devices");
+ /* Figure out where the next device config is, based on the last one. */
+ if (devices.lastdev)
+ p = device_config(devices.lastdev)
+ + devices.lastdev->desc->config_len;
+ else
+ p = devices.descpage;
- /* Copy in the new config header: type then length. */
- devices.descpage[devices.desc_used++] = type;
- devices.descpage[devices.desc_used++] = len;
- memcpy(devices.descpage + devices.desc_used, c, len);
- devices.desc_used += len;
+ /* We only have one page for all the descriptors. */
+ if (p + sizeof(d) > (void *)devices.descpage + getpagesize())
+ errx(1, "Too many devices");
- /* Update the device descriptor length: two byte head then data. */
- dev->desc->config_len += 2 + len;
+ /* p might not be aligned, so we memcpy in. */
+ return memcpy(p, &d, sizeof(d));
}
-/* This routine adds a virtqueue to a device. We specify how many descriptors
- * the virtqueue is to have. */
+/* Each device descriptor is followed by the description of its virtqueues. We
+ * specify how many descriptors the virtqueue is to have. */
static void add_virtqueue(struct device *dev, unsigned int num_descs,
void (*handle_output)(int fd, struct virtqueue *me))
{
/ getpagesize();
p = get_pages(pages);
+ /* Initialize the virtqueue */
+ vq->next = NULL;
+ vq->last_avail_idx = 0;
+ vq->dev = dev;
+
/* Initialize the configuration. */
vq->config.num = num_descs;
vq->config.irq = devices.next_irq++;
/* Initialize the vring. */
vring_init(&vq->vring, num_descs, p, getpagesize());
- /* Add the configuration information to this device's descriptor. */
- add_desc_field(dev, VIRTIO_CONFIG_F_VIRTQUEUE,
- sizeof(vq->config), &vq->config);
+ /* Append virtqueue to this device's descriptor. We use
+ * device_config() to get the end of the device's current virtqueues;
+ * we check that we haven't added any config or feature information
+ * yet, otherwise we'd be overwriting them. */
+ assert(dev->desc->config_len == 0 && dev->desc->feature_len == 0);
+ memcpy(device_config(dev), &vq->config, sizeof(vq->config));
+ dev->desc->num_vq++;
+
+ verbose("Virtqueue page %#lx\n", to_guest_phys(p));
/* Add to tail of list, so dev->vq is first vq, dev->vq->next is
* second. */
for (i = &dev->vq; *i; i = &(*i)->next);
*i = vq;
- /* Link virtqueue back to device. */
- vq->dev = dev;
-
/* Set the routine to call when the Guest does something to this
* virtqueue. */
vq->handle_output = handle_output;
- /* Set the "Don't Notify Me" flag if we don't have a handler */
+ /* As an optimization, set the advisory "Don't Notify Me" flag if we
+ * don't have a handler */
if (!handle_output)
vq->vring.used->flags = VRING_USED_F_NO_NOTIFY;
}
+/* The first half of the feature bitmask is for us to advertise features. The
+ * second half if for the Guest to accept features. */
+static void add_feature(struct device *dev, unsigned bit)
+{
+ u8 *features = get_feature_bits(dev);
+
+ /* We can't extend the feature bits once we've added config bytes */
+ if (dev->desc->feature_len <= bit / CHAR_BIT) {
+ assert(dev->desc->config_len == 0);
+ dev->desc->feature_len = (bit / CHAR_BIT) + 1;
+ }
+
+ features[bit / CHAR_BIT] |= (1 << (bit % CHAR_BIT));
+}
+
+/* This routine sets the configuration fields for an existing device's
+ * descriptor. It only works for the last device, but that's OK because that's
+ * how we use it. */
+static void set_config(struct device *dev, unsigned len, const void *conf)
+{
+ /* Check we haven't overflowed our single page. */
+ if (device_config(dev) + len > devices.descpage + getpagesize())
+ errx(1, "Too many devices");
+
+ /* Copy in the config information, and store the length. */
+ memcpy(device_config(dev), conf, len);
+ dev->desc->config_len = len;
+}
+
/* This routine does all the creation and setup of a new device, including
* calling new_dev_desc() to allocate the descriptor and device memory. */
static struct device *new_device(const char *name, u16 type, int fd,
{
struct device *dev = malloc(sizeof(*dev));
- /* Append to device list. Prepending to a single-linked list is
- * easier, but the user expects the devices to be arranged on the bus
- * in command-line order. The first network device on the command line
- * is eth0, the first block device /dev/vda, etc. */
- *devices.lastdev = dev;
- dev->next = NULL;
- devices.lastdev = &dev->next;
-
/* Now we populate the fields one at a time. */
dev->fd = fd;
/* If we have an input handler for this file descriptor, then we add it
dev->desc = new_dev_desc(type);
dev->handle_input = handle_input;
dev->name = name;
+ dev->vq = NULL;
+
+ /* Append to device list. Prepending to a single-linked list is
+ * easier, but the user expects the devices to be arranged on the bus
+ * in command-line order. The first network device on the command line
+ * is eth0, the first block device /dev/vda, etc. */
+ if (devices.lastdev)
+ devices.lastdev->next = dev;
+ else
+ devices.dev = dev;
+ devices.lastdev = dev;
+
return dev;
}
int netfd, ipfd;
u32 ip;
const char *br_name = NULL;
- u8 hwaddr[6];
+ struct virtio_net_config conf;
/* We open the /dev/net/tun device and tell it we want a tap device. A
* tap device is like a tun device, only somehow different. To tell
ip = str2ip(arg);
/* Set up the tun device, and get the mac address for the interface. */
- configure_device(ipfd, ifr.ifr_name, ip, hwaddr);
+ configure_device(ipfd, ifr.ifr_name, ip, conf.mac);
/* Tell Guest what MAC address to use. */
- add_desc_field(dev, VIRTIO_CONFIG_NET_MAC_F, sizeof(hwaddr), hwaddr);
+ add_feature(dev, VIRTIO_NET_F_MAC);
+ set_config(dev, sizeof(conf), &conf);
- /* We don't seed the socket any more; setup is done. */
+ /* We don't need the socket any more; setup is done. */
close(ipfd);
verbose("device %u: tun net %u.%u.%u.%u\n",
struct device *dev;
struct vblk_info *vblk;
void *stack;
- u64 cap;
- unsigned int val;
+ struct virtio_blk_config conf;
/* This is the pipe the I/O thread will use to tell us I/O is done. */
pipe(p);
vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE);
vblk->len = lseek64(vblk->fd, 0, SEEK_END);
+ /* We support barriers. */
+ add_feature(dev, VIRTIO_BLK_F_BARRIER);
+
/* Tell Guest how many sectors this device has. */
- cap = cpu_to_le64(vblk->len / 512);
- add_desc_field(dev, VIRTIO_CONFIG_BLK_F_CAPACITY, sizeof(cap), &cap);
+ conf.capacity = cpu_to_le64(vblk->len / 512);
/* Tell Guest not to put in too many descriptors at once: two are used
* for the in and out elements. */
- val = cpu_to_le32(VIRTQUEUE_NUM - 2);
- add_desc_field(dev, VIRTIO_CONFIG_BLK_F_SEG_MAX, sizeof(val), &val);
+ add_feature(dev, VIRTIO_BLK_F_SEG_MAX);
+ conf.seg_max = cpu_to_le32(VIRTQUEUE_NUM - 2);
+
+ set_config(dev, sizeof(conf), &conf);
/* The I/O thread writes to this end of the pipe when done. */
vblk->done_fd = p[1];
/* Create stack for thread and run it */
stack = malloc(32768);
- if (clone(io_thread, stack + 32768, CLONE_VM, dev) == -1)
+ /* SIGCHLD - We dont "wait" for our cloned thread, so prevent it from
+ * becoming a zombie. */
+ if (clone(io_thread, stack + 32768, CLONE_VM | SIGCHLD, dev) == -1)
err(1, "Creating clone");
/* We don't need to keep the I/O thread's end of the pipes open. */
close(vblk->workpipe[0]);
verbose("device %u: virtblock %llu sectors\n",
- devices.device_num, cap);
+ devices.device_num, le64_to_cpu(conf.capacity));
+}
+/* That's the end of device setup. :*/
+
+/* Reboot */
+static void __attribute__((noreturn)) restart_guest(void)
+{
+ unsigned int i;
+
+ /* Closing pipes causes the waker thread and io_threads to die, and
+ * closing /dev/lguest cleans up the Guest. Since we don't track all
+ * open fds, we simply close everything beyond stderr. */
+ for (i = 3; i < FD_SETSIZE; i++)
+ close(i);
+ execv(main_args[0], main_args);
+ err(1, "Could not exec %s", main_args[0]);
}
-/* That's the end of device setup. */
/*L:220 Finally we reach the core of the Launcher, which runs the Guest, serves
* its input and output, and finally, lays it to rest. */
int readval;
/* We read from the /dev/lguest device to run the Guest. */
- readval = read(lguest_fd, ¬ify_addr, sizeof(notify_addr));
+ readval = pread(lguest_fd, ¬ify_addr,
+ sizeof(notify_addr), cpu_id);
/* One unsigned long means the Guest did HCALL_NOTIFY */
if (readval == sizeof(notify_addr)) {
/* ENOENT means the Guest died. Reading tells us why. */
} else if (errno == ENOENT) {
char reason[1024] = { 0 };
- read(lguest_fd, reason, sizeof(reason)-1);
+ pread(lguest_fd, reason, sizeof(reason)-1, cpu_id);
errx(1, "%s", reason);
+ /* ERESTART means that we need to reboot the guest */
+ } else if (errno == ERESTART) {
+ restart_guest();
/* EAGAIN means the Waker wanted us to look at some input.
* Anything else means a bug or incompatible change. */
} else if (errno != EAGAIN)
err(1, "Running guest failed");
+ /* Only service input on thread for CPU 0. */
+ if (cpu_id != 0)
+ continue;
+
/* Service input, then unset the BREAK to release the Waker. */
handle_input(lguest_fd);
- if (write(lguest_fd, args, sizeof(args)) < 0)
+ if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
err(1, "Resetting break");
}
}
/* If they specify an initrd file to load. */
const char *initrd_name = NULL;
+ /* Save the args: we "reboot" by execing ourselves again. */
+ main_args = argv;
+ /* We don't "wait" for the children, so prevent them from becoming
+ * zombies. */
+ signal(SIGCHLD, SIG_IGN);
+
/* First we initialize the device list. Since console and network
* device receive input from a file descriptor, we keep an fdset
* (infds) and the maximum fd number (max_infd) with the head of the
- * list. We also keep a pointer to the last device, for easy appending
- * to the list. Finally, we keep the next interrupt number to hand out
- * (1: remember that 0 is used by the timer). */
+ * list. We also keep a pointer to the last device. Finally, we keep
+ * the next interrupt number to hand out (1: remember that 0 is used by
+ * the timer). */
FD_ZERO(&devices.infds);
devices.max_infd = -1;
- devices.lastdev = &devices.dev;
+ devices.lastdev = NULL;
devices.next_irq = 1;
+ cpu_id = 0;
/* We need to know how much memory so we can set up the device
* descriptor and memory pages for the devices as we parse the command
* line. So we quickly look through the arguments to find the amount
git.samba.org / sfrench / cifs-2.6.git / blobdiff