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Commit 17cbca2b authored by Rusty Russell's avatar Rusty Russell
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Update example launcher for virtio 

Implements virtio-based console, network and block servers.  The block
server uses a thread so it's async, which is an improvement over the
old synchronous implementation (but a little more complex).
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 19f1537b
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Showing with 681 additions and 462 deletions
Documentation/lguest/lguest.c
View file @ 17cbca2b
......@@ -32,7 +32,9 @@
#include <termios.h>
#include <getopt.h>
#include <zlib.h>
/*L:110 We can ignore the 28 include files we need for this program, but I do
#include <assert.h>
#include <sched.h>
/*L:110 We can ignore the 30 include files we need for this program, but I do
* want to draw attention to the use of kernel-style types.
*
* As Linus said, "C is a Spartan language, and so should your naming be." I
......@@ -44,6 +46,12 @@ typedef uint32_t u32;
typedef uint16_t u16;
typedef uint8_t u8;
#include "linux/lguest_launcher.h"
#include "linux/pci_ids.h"
#include "linux/virtio_config.h"
#include "linux/virtio_net.h"
#include "linux/virtio_blk.h"
#include "linux/virtio_console.h"
#include "linux/virtio_ring.h"
#include "asm-x86/e820.h"
/*:*/
......@@ -55,6 +63,8 @@ typedef uint8_t u8;
#endif
/* We can have up to 256 pages for devices. */
#define DEVICE_PAGES 256
/* This fits nicely in a single 4096-byte page. */
#define VIRTQUEUE_NUM 127
/*L:120 verbose is both a global flag and a macro. The C preprocessor allows
* this, and although I wouldn't recommend it, it works quite nicely here. */
......@@ -78,8 +88,17 @@ struct device_list
fd_set infds;
int max_infd;
/* Counter to assign interrupt numbers. */
unsigned int next_irq;
/* Counter to print out convenient device numbers. */
unsigned int device_num;
/* The descriptor page for the devices. */
struct lguest_device_desc *descs;
u8 *descpage;
/* The tail of the last descriptor. */
unsigned int desc_used;
/* A single linked list of devices. */
struct device *dev;
......@@ -87,31 +106,88 @@ struct device_list
struct device **lastdev;
};
/* The list of Guest devices, based on command line arguments. */
static struct device_list devices;
/* The device structure describes a single device. */
struct device
{
/* The linked-list pointer. */
struct device *next;
/* The descriptor for this device, as mapped into the Guest. */
/* The this device's descriptor, as mapped into the Guest. */
struct lguest_device_desc *desc;
/* The memory page(s) of this device, if any. Also mapped in Guest. */
void *mem;
/* The name of this device, for --verbose. */
const char *name;
/* If handle_input is set, it wants to be called when this file
* descriptor is ready. */
int fd;
bool (*handle_input)(int fd, struct device *me);
/* If handle_output is set, it wants to be called when the Guest sends
* DMA to this key. */
unsigned long watch_key;
u32 (*handle_output)(int fd, const struct iovec *iov,
unsigned int num, struct device *me);
/* Any queues attached to this device */
struct virtqueue *vq;
/* Device-specific data. */
void *priv;
};
/* The virtqueue structure describes a queue attached to a device. */
struct virtqueue
{
struct virtqueue *next;
/* Which device owns me. */
struct device *dev;
/* The configuration for this queue. */
struct lguest_vqconfig config;
/* The actual ring of buffers. */
struct vring vring;
/* Last available index we saw. */
u16 last_avail_idx;
/* The routine to call when the Guest pings us. */
void (*handle_output)(int fd, struct virtqueue *me);
};
/* 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()
/* Convert an iovec element to the given type.
*
* This is a fairly ugly trick: we need to know the size of the type and
* alignment requirement to check the pointer is kosher. It's also nice to
* have the name of the type in case we report failure.
*
* Typing those three things all the time is cumbersome and error prone, so we
* have a macro which sets them all up and passes to the real function. */
#define convert(iov, type) \
((type *)_convert((iov), sizeof(type), __alignof__(type), #type))
static void *_convert(struct iovec *iov, size_t size, size_t align,
const char *name)
{
if (iov->iov_len != size)
errx(1, "Bad iovec size %zu for %s", iov->iov_len, name);
if ((unsigned long)iov->iov_base % align != 0)
errx(1, "Bad alignment %p for %s", iov->iov_base, name);
return iov->iov_base;
}
/* The virtio configuration space is defined to be little-endian. x86 is
* little-endian too, but it's nice to be explicit so we have these helpers. */
#define cpu_to_le16(v16) (v16)
#define cpu_to_le32(v32) (v32)
#define cpu_to_le64(v64) (v64)
#define le16_to_cpu(v16) (v16)
#define le32_to_cpu(v32) (v32)
#define le64_to_cpu(v32) (v64)
/*L:100 The Launcher code itself takes us out into userspace, that scary place
* where pointers run wild and free! Unfortunately, like most userspace
* programs, it's quite boring (which is why everyone likes to hack on the
......@@ -486,11 +562,11 @@ static int tell_kernel(unsigned long pgdir, unsigned long start)
}
/*:*/
static void set_fd(int fd, struct device_list *devices)
static void add_device_fd(int fd)
{
FD_SET(fd, &devices->infds);
if (fd > devices->max_infd)
devices->max_infd = fd;
FD_SET(fd, &devices.infds);
if (fd > devices.max_infd)
devices.max_infd = fd;
}
/*L:200
......@@ -508,18 +584,18 @@ static void set_fd(int fd, struct device_list *devices)
*
* This, of course, is merely a different *kind* of icky.
*/
static void wake_parent(int pipefd, int lguest_fd, struct device_list *devices)
static void wake_parent(int pipefd, int lguest_fd)
{
/* Add the pipe from the Launcher to the fdset in the device_list, so
* we watch it, too. */
set_fd(pipefd, devices);
add_device_fd(pipefd);
for (;;) {
fd_set rfds = devices->infds;
fd_set rfds = devices.infds;
unsigned long args[] = { LHREQ_BREAK, 1 };
/* Wait until input is ready from one of the devices. */
select(devices->max_infd+1, &rfds, NULL, NULL, NULL);
select(devices.max_infd+1, &rfds, NULL, NULL, NULL);
/* Is it a message from the Launcher? */
if (FD_ISSET(pipefd, &rfds)) {
int ignorefd;
......@@ -530,14 +606,14 @@ static void wake_parent(int pipefd, int lguest_fd, struct device_list *devices)
/* Otherwise it's telling us there's a problem with one
* of the devices, and we should ignore that file
* descriptor from now on. */
FD_CLR(ignorefd, &devices->infds);
FD_CLR(ignorefd, &devices.infds);
} else /* Send LHREQ_BREAK command. */
write(lguest_fd, args, sizeof(args));
}
}
/* This routine just sets up a pipe to the Waker process. */
static int setup_waker(int lguest_fd, struct device_list *device_list)
static int setup_waker(int lguest_fd)
{
int pipefd[2], child;
......@@ -551,7 +627,7 @@ static int setup_waker(int lguest_fd, struct device_list *device_list)
if (child == 0) {
/* Close the "writing" end of our copy of the pipe */
close(pipefd[1]);
wake_parent(pipefd[0], lguest_fd, device_list);
wake_parent(pipefd[0], lguest_fd);
}
/* Close the reading end of our copy of the pipe. */
close(pipefd[0]);
......@@ -574,7 +650,7 @@ static void *_check_pointer(unsigned long addr, unsigned int size,
/* We have to separately check addr and addr+size, because size could
* be huge and addr + size might wrap around. */
if (addr >= guest_limit || addr + size >= guest_limit)
errx(1, "%s:%i: Invalid address %li", __FILE__, line, addr);
errx(1, "%s:%i: Invalid address %#lx", __FILE__, line, addr);
/* We return a pointer for the caller's convenience, now we know it's
* safe to use. */
return from_guest_phys(addr);
......@@ -582,74 +658,131 @@ static void *_check_pointer(unsigned long addr, unsigned int size,
/* A macro which transparently hands the line number to the real function. */
#define check_pointer(addr,size) _check_pointer(addr, size, __LINE__)
/* The Guest has given us the address of a "struct lguest_dma". We check it's
* OK and convert it to an iovec (which is a simple array of ptr/size
* pairs). */
static u32 *dma2iov(unsigned long dma, struct iovec iov[], unsigned *num)
/* This simply sets up an iovec array where we can put data to be discarded.
* This happens when the Guest doesn't want or can't handle the input: we have
* to get rid of it somewhere, and if we bury it in the ceiling space it will
* start to smell after a week. */
static void discard_iovec(struct iovec *iov, unsigned int *num)
{
unsigned int i;
struct lguest_dma *udma;
/* First we make sure that the array memory itself is valid. */
udma = check_pointer(dma, sizeof(*udma));
/* Now we check each element */
for (i = 0; i < LGUEST_MAX_DMA_SECTIONS; i++) {
/* A zero length ends the array. */
if (!udma->len[i])
break;
static char discard_buf[1024];
*num = 1;
iov->iov_base = discard_buf;
iov->iov_len = sizeof(discard_buf);
}
iov[i].iov_base = check_pointer(udma->addr[i], udma->len[i]);
iov[i].iov_len = udma->len[i];
}
*num = i;
/* This function returns the next descriptor in the chain, or vq->vring.num. */
static unsigned next_desc(struct virtqueue *vq, unsigned int i)
{
unsigned int next;
/* If this descriptor says it doesn't chain, we're done. */
if (!(vq->vring.desc[i].flags & VRING_DESC_F_NEXT))
return vq->vring.num;
/* Check they're not leading us off end of descriptors. */
next = vq->vring.desc[i].next;
/* Make sure compiler knows to grab that: we don't want it changing! */
wmb();
if (next >= vq->vring.num)
errx(1, "Desc next is %u", next);
return next;
}
/* This looks in the virtqueue and for the first available buffer, and converts
* it to an iovec for convenient access. Since descriptors consist of some
* number of output then some number of input descriptors, it's actually two
* iovecs, but we pack them into one and note how many of each there were.
*
* This function returns the descriptor number found, or vq->vring.num (which
* is never a valid descriptor number) if none was found. */
static unsigned get_vq_desc(struct virtqueue *vq,
struct iovec iov[],
unsigned int *out_num, unsigned int *in_num)
{
unsigned int i, head;
/* Check it isn't doing very strange things with descriptor numbers. */
if ((u16)(vq->vring.avail->idx - vq->last_avail_idx) > vq->vring.num)
errx(1, "Guest moved used index from %u to %u",
vq->last_avail_idx, vq->vring.avail->idx);
/* If there's nothing new since last we looked, return invalid. */
if (vq->vring.avail->idx == vq->last_avail_idx)
return vq->vring.num;
/* Grab the next descriptor number they're advertising, and increment
* the index we've seen. */
head = vq->vring.avail->ring[vq->last_avail_idx++ % vq->vring.num];
/* If their number is silly, that's a fatal mistake. */
if (head >= vq->vring.num)
errx(1, "Guest says index %u is available", head);
/* When we start there are none of either input nor output. */
*out_num = *in_num = 0;
i = head;
do {
/* Grab the first descriptor, and check it's OK. */
iov[*out_num + *in_num].iov_len = vq->vring.desc[i].len;
iov[*out_num + *in_num].iov_base
= check_pointer(vq->vring.desc[i].addr,
vq->vring.desc[i].len);
/* If this is an input descriptor, increment that count. */
if (vq->vring.desc[i].flags & VRING_DESC_F_WRITE)
(*in_num)++;
else {
/* If it's an output descriptor, they're all supposed
* to come before any input descriptors. */
if (*in_num)
errx(1, "Descriptor has out after in");
(*out_num)++;
}
/* If we've got too many, that implies a descriptor loop. */
if (*out_num + *in_num > vq->vring.num)
errx(1, "Looped descriptor");
} while ((i = next_desc(vq, i)) != vq->vring.num);
/* We return the pointer to where the caller should write the amount of
* the buffer used. */
return &udma->used_len;
return head;
}
/* This routine gets a DMA buffer from the Guest for a given key, and converts
* it to an iovec array. It returns the interrupt the Guest wants when we're
* finished, and a pointer to the "used_len" field to fill in. */
static u32 *get_dma_buffer(int fd, void *key,
struct iovec iov[], unsigned int *num, u32 *irq)
/* Once we've used one of their buffers, we tell them about it. We'll then
* want to send them an interrupt, using trigger_irq(). */
static void add_used(struct virtqueue *vq, unsigned int head, int len)
{
unsigned long buf[] = { LHREQ_GETDMA, to_guest_phys(key) };
unsigned long udma;
u32 *res;
/* Ask the kernel for a DMA buffer corresponding to this key. */
udma = write(fd, buf, sizeof(buf));
/* They haven't registered any, or they're all used? */
if (udma == (unsigned long)-1)
return NULL;
/* Convert it into our iovec array */
res = dma2iov(udma, iov, num);
/* The kernel stashes irq in ->used_len to get it out to us. */
*irq = *res;
/* Return a pointer to ((struct lguest_dma *)udma)->used_len. */
return res;
struct vring_used_elem *used;
/* Get a pointer to the next entry in the used ring. */
used = &vq->vring.used->ring[vq->vring.used->idx % vq->vring.num];
used->id = head;
used->len = len;
/* Make sure buffer is written before we update index. */
wmb();
vq->vring.used->idx++;
}
/* This is a convenient routine to send the Guest an interrupt. */
static void trigger_irq(int fd, u32 irq)
/* This actually sends the interrupt for this virtqueue */
static void trigger_irq(int fd, struct virtqueue *vq)
{
unsigned long buf[] = { LHREQ_IRQ, irq };
unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
return;
/* Send the Guest an interrupt tell them we used something up. */
if (write(fd, buf, sizeof(buf)) != 0)
err(1, "Triggering irq %i", irq);
err(1, "Triggering irq %i", vq->config.irq);
}
/* This simply sets up an iovec array where we can put data to be discarded.
* This happens when the Guest doesn't want or can't handle the input: we have
* to get rid of it somewhere, and if we bury it in the ceiling space it will
* start to smell after a week. */
static void discard_iovec(struct iovec *iov, unsigned int *num)
/* And here's the combo meal deal. Supersize me! */
static void add_used_and_trigger(int fd, struct virtqueue *vq,
unsigned int head, int len)
{
static char discard_buf[1024];
*num = 1;
iov->iov_base = discard_buf;
iov->iov_len = sizeof(discard_buf);
add_used(vq, head, len);
trigger_irq(fd, vq);
}
/* Here is the input terminal setting we save, and the routine to restore them
......@@ -672,38 +805,37 @@ struct console_abort
/* This is the routine which handles console input (ie. stdin). */
static bool handle_console_input(int fd, struct device *dev)
{
u32 irq = 0, *lenp;
int len;
unsigned int num;
struct iovec iov[LGUEST_MAX_DMA_SECTIONS];
unsigned int head, in_num, out_num;
struct iovec iov[dev->vq->vring.num];
struct console_abort *abort = dev->priv;
/* First we get the console buffer from the Guest. The key is dev->mem
* which was set to 0 in setup_console(). */
lenp = get_dma_buffer(fd, dev->mem, iov, &num, &irq);
if (!lenp) {
/* If it's not ready for input, warn and set up to discard. */
warn("console: no dma buffer!");
discard_iovec(iov, &num);
}
/* First we need a console buffer from the Guests's input virtqueue. */
head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
if (head == dev->vq->vring.num) {
/* If they're not ready for input, we warn and set up to
* discard. */
warnx("console: no dma buffer!");
discard_iovec(iov, &in_num);
} else if (out_num)
errx(1, "Output buffers in console in queue?");
/* This is why we convert to iovecs: the readv() call uses them, and so
* it reads straight into the Guest's buffer. */
len = readv(dev->fd, iov, num);
len = readv(dev->fd, iov, in_num);
if (len <= 0) {
/* This implies that the console is closed, is /dev/null, or
* something went terribly wrong. We still go through the rest
* of the logic, though, especially the exit handling below. */
* something went terribly wrong. */
warnx("Failed to get console input, ignoring console.");
len = 0;
/* Put the input terminal back and return failure (meaning,
* don't call us again). */
restore_term();
return false;
}
/* If we read the data into the Guest, fill in the length and send the
* interrupt. */
if (lenp) {
*lenp = len;
trigger_irq(fd, irq);
}
/* If we actually read the data into the Guest, tell them about it. */
if (head != dev->vq->vring.num)
add_used_and_trigger(fd, dev->vq, head, len);
/* Three ^C within one second? Exit.
*
......@@ -732,202 +864,137 @@ static bool handle_console_input(int fd, struct device *dev)
/* Any other key resets the abort counter. */
abort->count = 0;
/* Now, if we didn't read anything, put the input terminal back and
* return failure (meaning, don't call us again). */
if (!len) {
restore_term();
return false;
}
/* Everything went OK! */
return true;
}
/* Handling console output is much simpler than input. */
static u32 handle_console_output(int fd, const struct iovec *iov,
unsigned num, struct device*dev)
/* Handling output for console is simple: we just get all the output buffers
* and write them to stdout. */
static void handle_console_output(int fd, struct virtqueue *vq)
{
/* Whatever the Guest sends, write it to standard output. Return the
* number of bytes written. */
return writev(STDOUT_FILENO, iov, num);
}
/* Guest->Host network output is also pretty easy. */
static u32 handle_tun_output(int fd, const struct iovec *iov,
unsigned num, struct device *dev)
{
/* We put a flag in the "priv" pointer of the network device, and set
* it as soon as we see output. We'll see why in handle_tun_input() */
*(bool *)dev->priv = true;
/* Whatever packet the Guest sent us, write it out to the tun
* device. */
return writev(dev->fd, iov, num);
unsigned int head, out, in;
int len;
struct iovec iov[vq->vring.num];
/* Keep getting output buffers from the Guest until we run out. */
while ((head = get_vq_desc(vq, iov, &out, &in)) != vq->vring.num) {
if (in)
errx(1, "Input buffers in output queue?");
len = writev(STDOUT_FILENO, iov, out);
add_used_and_trigger(fd, vq, head, len);
}
}
/* This matches the peer_key() in lguest_net.c. The key for any given slot
* is the address of the network device's page plus 4 * the slot number. */
static unsigned long peer_offset(unsigned int peernum)
/* Handling output for network is also simple: we get all the output buffers
* and write them (ignoring the first element) to this device's file descriptor
* (stdout). */
static void handle_net_output(int fd, struct virtqueue *vq)
{
return 4 * peernum;
unsigned int head, out, in;
int len;
struct iovec iov[vq->vring.num];
/* Keep getting output buffers from the Guest until we run out. */
while ((head = get_vq_desc(vq, iov, &out, &in)) != vq->vring.num) {
if (in)
errx(1, "Input buffers in output queue?");
/* Check header, but otherwise ignore it (we said we supported
* no features). */
(void)convert(&iov[0], struct virtio_net_hdr);
len = writev(vq->dev->fd, iov+1, out-1);
add_used_and_trigger(fd, vq, head, len);
}
}
/* This is where we handle a packet coming in from the tun device */
/* This is where we handle a packet coming in from the tun device to our
* Guest. */
static bool handle_tun_input(int fd, struct device *dev)
{
u32 irq = 0, *lenp;
unsigned int head, in_num, out_num;
int len;
unsigned num;
struct iovec iov[LGUEST_MAX_DMA_SECTIONS];
struct iovec iov[dev->vq->vring.num];
struct virtio_net_hdr *hdr;
/* First we get a buffer the Guest has bound to its key. */
lenp = get_dma_buffer(fd, dev->mem+peer_offset(NET_PEERNUM), iov, &num,
&irq);
if (!lenp) {
/* First we need a network buffer from the Guests's recv virtqueue. */
head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
if (head == dev->vq->vring.num) {
/* Now, it's expected that if we try to send a packet too
* early, the Guest won't be ready yet. This is why we set a
* flag when the Guest sends its first packet. If it's sent a
* packet we assume it should be ready to receive them.
*
* Actually, this is what the status bits in the descriptor are
* for: we should *use* them. FIXME! */
if (*(bool *)dev->priv)
* early, the Guest won't be ready yet. Wait until the device
* status says it's ready. */
/* FIXME: Actually want DRIVER_ACTIVE here. */
if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK)
warn("network: no dma buffer!");
discard_iovec(iov, &num);
}
discard_iovec(iov, &in_num);
} else if (out_num)
errx(1, "Output buffers in network recv queue?");
/* First element is the header: we set it to 0 (no features). */
hdr = convert(&iov[0], struct virtio_net_hdr);
hdr->flags = 0;
hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
/* Read the packet from the device directly into the Guest's buffer. */
len = readv(dev->fd, iov, num);
len = readv(dev->fd, iov+1, in_num-1);
if (len <= 0)
err(1, "reading network");
/* Write the used_len, and trigger the interrupt for the Guest */
if (lenp) {
*lenp = len;
trigger_irq(fd, irq);
}
/* If we actually read the data into the Guest, tell them about it. */
if (head != dev->vq->vring.num)
add_used_and_trigger(fd, dev->vq, head, sizeof(*hdr) + len);
verbose("tun input packet len %i [%02x %02x] (%s)\n", len,
((u8 *)iov[0].iov_base)[0], ((u8 *)iov[0].iov_base)[1],
lenp ? "sent" : "discarded");
((u8 *)iov[1].iov_base)[0], ((u8 *)iov[1].iov_base)[1],
head != dev->vq->vring.num ? "sent" : "discarded");
/* All good. */
return true;
}
/* The last device handling routine is block output: the Guest has sent a DMA
* to the block device. It will have placed the command it wants in the
* "struct lguest_block_page". */
static u32 handle_block_output(int fd, const struct iovec *iov,
unsigned num, struct device *dev)
{
struct lguest_block_page *p = dev->mem;
u32 irq, *lenp;
unsigned int len, reply_num;
struct iovec reply[LGUEST_MAX_DMA_SECTIONS];
off64_t device_len, off = (off64_t)p->sector * 512;
/* First we extract the device length from the dev->priv pointer. */
device_len = *(off64_t *)dev->priv;
/* We first check that the read or write is within the length of the
* block file. */
if (off >= device_len)
errx(1, "Bad offset %llu vs %llu", off, device_len);
/* Move to the right location in the block file. This shouldn't fail,
* but best to check. */
if (lseek64(dev->fd, off, SEEK_SET) != off)
err(1, "Bad seek to sector %i", p->sector);
verbose("Block: %s at offset %llu\n", p->type ? "WRITE" : "READ", off);
/* They were supposed to bind a reply buffer at key equal to the start
* of the block device memory. We need this to tell them when the
* request is finished. */
lenp = get_dma_buffer(fd, dev->mem, reply, &reply_num, &irq);
if (!lenp)
err(1, "Block request didn't give us a dma buffer");
if (p->type) {
/* A write request. The DMA they sent contained the data, so
* write it out. */
len = writev(dev->fd, iov, num);
/* Grr... Now we know how long the "struct lguest_dma" they
* sent was, we make sure they didn't try to write over the end
* of the block file (possibly extending it). */
if (off + len > device_len) {
/* Trim it back to the correct length */
ftruncate64(dev->fd, device_len);
/* Die, bad Guest, die. */
errx(1, "Write past end %llu+%u", off, len);
}
/* The reply length is 0: we just send back an empty DMA to
* interrupt them and tell them the write is finished. */
*lenp = 0;
} else {
/* A read request. They sent an empty DMA to start the
* request, and we put the read contents into the reply
* buffer. */
len = readv(dev->fd, reply, reply_num);
*lenp = len;
}
/* The result is 1 (done), 2 if there was an error (short read or
* write). */
p->result = 1 + (p->bytes != len);
/* Now tell them we've used their reply buffer. */
trigger_irq(fd, irq);
/* We're supposed to return the number of bytes of the output buffer we
* used. But the block device uses the "result" field instead, so we
* don't bother. */
return 0;
}
/* This is the generic routine we call when the Guest sends some DMA out. */
static void handle_output(int fd, unsigned long dma, unsigned long key,
struct device_list *devices)
/* 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;
u32 *lenp;
struct iovec iov[LGUEST_MAX_DMA_SECTIONS];
unsigned num = 0;
/* Convert the "struct lguest_dma" they're sending to a "struct
* iovec". */
lenp = dma2iov(dma, iov, &num);
/* Check each device: if they expect output to this key, tell them to
* handle it. */
for (i = devices->dev; i; i = i->next) {
if (i->handle_output && key == i->watch_key) {
/* We write the result straight into the used_len field
* for them. */
*lenp = i->handle_output(fd, iov, num, i);
return;
struct virtqueue *vq;
/* Check each virtqueue. */
for (i = devices.dev; i; i = i->next) {
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);
return;
}
}
}
/* This can happen: the kernel sends any SEND_DMA which doesn't match
* another Guest to us. It could be that another Guest just left a
* network, for example. But it's unusual. */
warnx("Pending dma %p, key %p", (void *)dma, (void *)key);
/* Early console write is done using notify on a nul-terminated string
* in Guest memory. */
if (addr >= guest_limit)
errx(1, "Bad NOTIFY %#lx", addr);
write(STDOUT_FILENO, from_guest_phys(addr),
strnlen(from_guest_phys(addr), guest_limit - addr));
}
/* This is called when the waker wakes us up: check for incoming file
* descriptors. */
static void handle_input(int fd, struct device_list *devices)
static void handle_input(int fd)
{
/* select() wants a zeroed timeval to mean "don't wait". */
struct timeval poll = { .tv_sec = 0, .tv_usec = 0 };
for (;;) {
struct device *i;
fd_set fds = devices->infds;
fd_set fds = devices.infds;
/* If nothing is ready, we're done. */
if (select(devices->max_infd+1, &fds, NULL, NULL, &poll) == 0)
if (select(devices.max_infd+1, &fds, NULL, NULL, &poll) == 0)
break;
/* Otherwise, call the device(s) which have readable
* file descriptors and a method of handling them. */
for (i = devices->dev; i; i = i->next) {
for (i = devices.dev; i; i = i->next) {
if (i->handle_input && FD_ISSET(i->fd, &fds)) {
/* If handle_input() returns false, it means we
* should no longer service it.
......@@ -936,7 +1003,7 @@ static void handle_input(int fd, struct device_list *devices)
/* Clear it from the set of input file
* descriptors kept at the head of the
* device list. */
FD_CLR(i->fd, &devices->infds);
FD_CLR(i->fd, &devices.infds);
/* Tell waker to ignore it too... */
write(waker_fd, &i->fd, sizeof(i->fd));
}
......@@ -953,43 +1020,93 @@ static void handle_input(int fd, struct device_list *devices)
* routines to allocate them.
*
* This routine allocates a new "struct lguest_device_desc" from descriptor
* table in the devices array just above the Guest's normal memory. */
static struct lguest_device_desc *
new_dev_desc(struct lguest_device_desc *descs,
u16 type, u16 features, u16 num_pages)
* 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)
{
unsigned int i;
struct lguest_device_desc *d;
for (i = 0; i < LGUEST_MAX_DEVICES; i++) {
if (!descs[i].type) {
descs[i].type = type;
descs[i].features = features;
descs[i].num_pages = num_pages;
/* If they said the device needs memory, we allocate
* that now. */
if (num_pages) {
unsigned long pa;
pa = to_guest_phys(get_pages(num_pages));
descs[i].pfn = pa / getpagesize();
}
return &descs[i];
}
}
errx(1, "too many devices");
/* We only have one page for all the descriptors. */
if (devices.desc_used + sizeof(*d) > getpagesize())
errx(1, "Too many devices");
/* 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;
}
/* Each device descriptor is followed by some configuration information.
* The first byte is a "status" byte for the Guest to report what's happening.
* After that are fields: 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 is the last descriptor, right? */
assert(devices.descpage + devices.desc_used
== (u8 *)(dev->desc + 1) + dev->desc->config_len);
/* We only have one page of device descriptions. */
if (devices.desc_used + 2 + len > getpagesize())
errx(1, "Too many devices");
/* 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;
/* Update the device descriptor length: two byte head then data. */
dev->desc->config_len += 2 + len;
}
/* This routine adds a virtqueue to a device. 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))
{
unsigned int pages;
struct virtqueue **i, *vq = malloc(sizeof(*vq));
void *p;
/* First we need some pages for this virtqueue. */
pages = (vring_size(num_descs) + getpagesize() - 1) / getpagesize();
p = get_pages(pages);
/* Initialize the configuration. */
vq->config.num = num_descs;
vq->config.irq = devices.next_irq++;
vq->config.pfn = to_guest_phys(p) / getpagesize();
/* Initialize the vring. */
vring_init(&vq->vring, num_descs, p);
/* Add the configuration information to this device's descriptor. */
add_desc_field(dev, VIRTIO_CONFIG_F_VIRTQUEUE,
sizeof(vq->config), &vq->config);
/* 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 up handler. */
vq->handle_output = handle_output;
if (!handle_output)
vq->vring.used->flags = VRING_USED_F_NO_NOTIFY;
}
/* This monster routine does all the creation and setup of a new device,
* including caling new_dev_desc() to allocate the descriptor and device
* memory. */
static struct device *new_device(struct device_list *devices,
u16 type, u16 num_pages, u16 features,
int fd,
bool (*handle_input)(int, struct device *),
unsigned long watch_off,
u32 (*handle_output)(int,
const struct iovec *,
unsigned,
struct device *))
/* This routine does all the creation and setup of a new device, including
* caling new_dev_desc() to allocate the descriptor and device memory. */
static struct device *new_device(const char *name, u16 type, int fd,
bool (*handle_input)(int, struct device *))
{
struct device *dev = malloc(sizeof(*dev));
......@@ -997,27 +1114,25 @@ static struct device *new_device(struct device_list *devices,
* 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/lgba, etc. */
*devices->lastdev = dev;
*devices.lastdev = dev;
dev->next = NULL;
devices->lastdev = &dev->next;
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
* to the device_list's fdset and maxfd. */
if (handle_input)
set_fd(dev->fd, devices);
dev->desc = new_dev_desc(devices->descs, type, features, num_pages);
dev->mem = from_guest_phys(dev->desc->pfn * getpagesize());
add_device_fd(dev->fd);
dev->desc = new_dev_desc(type);
dev->handle_input = handle_input;
dev->watch_key = to_guest_phys(dev->mem) + watch_off;
dev->handle_output = handle_output;
dev->name = name;
return dev;
}
/* Our first setup routine is the console. It's a fairly simple device, but
* UNIX tty handling makes it uglier than it could be. */
static void setup_console(struct device_list *devices)
static void setup_console(void)
{
struct device *dev;
......@@ -1033,127 +1148,38 @@ static void setup_console(struct device_list *devices)
atexit(restore_term);
}
/* We don't currently require any memory for the console, so we ask for
* 0 pages. */
dev = new_device(devices, LGUEST_DEVICE_T_CONSOLE, 0, 0,
STDIN_FILENO, handle_console_input,
LGUEST_CONSOLE_DMA_KEY, handle_console_output);
dev = new_device("console", VIRTIO_ID_CONSOLE,
STDIN_FILENO, handle_console_input);
/* We store the console state in dev->priv, and initialize it. */
dev->priv = malloc(sizeof(struct console_abort));
((struct console_abort *)dev->priv)->count = 0;
verbose("device %p: console\n",
(void *)(dev->desc->pfn * getpagesize()));
}
/* Setting up a block file is also fairly straightforward. */
static void setup_block_file(const char *filename, struct device_list *devices)
{
int fd;
struct device *dev;
off64_t *device_len;
struct lguest_block_page *p;
/* We open with O_LARGEFILE because otherwise we get stuck at 2G. We
* open with O_DIRECT because otherwise our benchmarks go much too
* fast. */
fd = open_or_die(filename, O_RDWR|O_LARGEFILE|O_DIRECT);
/* We want one page, and have no input handler (the block file never
* has anything interesting to say to us). Our timing will be quite
* random, so it should be a reasonable randomness source. */
dev = new_device(devices, LGUEST_DEVICE_T_BLOCK, 1,
LGUEST_DEVICE_F_RANDOMNESS,
fd, NULL, 0, handle_block_output);
/* We store the device size in the private area */
device_len = dev->priv = malloc(sizeof(*device_len));
/* This is the safe way of establishing the size of our device: it
* might be a normal file or an actual block device like /dev/hdb. */
*device_len = lseek64(fd, 0, SEEK_END);
/* The device memory is a "struct lguest_block_page". It's zeroed
* already, we just need to put in the device size. Block devices
* think in sectors (ie. 512 byte chunks), so we translate here. */
p = dev->mem;
p->num_sectors = *device_len/512;
verbose("device %p: block %i sectors\n",
(void *)(dev->desc->pfn * getpagesize()), p->num_sectors);
/* The console needs two virtqueues: the input then the output. We
* don't care when they refill the input queue, since we don't hold
* data waiting for them. That's why the input queue's callback is
* NULL. */
add_virtqueue(dev, VIRTQUEUE_NUM, NULL);
add_virtqueue(dev, VIRTQUEUE_NUM, handle_console_output);
verbose("device %u: console\n", devices.device_num++);
}
/*:*/
/*
* Network Devices.
/*M:010 Inter-guest networking is an interesting area. Simplest is to have a
* --sharenet=<name> option which opens or creates a named pipe. This can be
* used to send packets to another guest in a 1:1 manner.
*
* Setting up network devices is quite a pain, because we have three types.
* First, we have the inter-Guest network. This is a file which is mapped into
* the address space of the Guests who are on the network. Because it is a
* shared mapping, the same page underlies all the devices, and they can send
* DMA to each other.
* More sopisticated is to use one of the tools developed for project like UML
* to do networking.
*
* Remember from our network driver, the Guest is told what slot in the page it
* is to use. We use exclusive fnctl locks to reserve a slot. If another
* Guest is using a slot, the lock will fail and we try another. Because fnctl
* locks are cleaned up automatically when we die, this cleverly means that our
* reservation on the slot will vanish if we crash. */
static unsigned int find_slot(int netfd, const char *filename)
{
struct flock fl;
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_len = 1;
/* Try a 1 byte lock in each possible position number */
for (fl.l_start = 0;
fl.l_start < getpagesize()/sizeof(struct lguest_net);
fl.l_start++) {
/* If we succeed, return the slot number. */
if (fcntl(netfd, F_SETLK, &fl) == 0)
return fl.l_start;
}
errx(1, "No free slots in network file %s", filename);
}
/* This function sets up the network file */
static void setup_net_file(const char *filename,
struct device_list *devices)
{
int netfd;
struct device *dev;
/* We don't use open_or_die() here: for friendliness we create the file
* if it doesn't already exist. */
netfd = open(filename, O_RDWR, 0);
if (netfd < 0) {
if (errno == ENOENT) {
netfd = open(filename, O_RDWR|O_CREAT, 0600);
if (netfd >= 0) {
/* If we succeeded, initialize the file with a
* blank page. */
char page[getpagesize()];
memset(page, 0, sizeof(page));
write(netfd, page, sizeof(page));
}
}
if (netfd < 0)
err(1, "cannot open net file '%s'", filename);
}
/* We need 1 page, and the features indicate the slot to use and that
* no checksum is needed. We never touch this device again; it's
* between the Guests on the network, so we don't register input or
* output handlers. */
dev = new_device(devices, LGUEST_DEVICE_T_NET, 1,
find_slot(netfd, filename)|LGUEST_NET_F_NOCSUM,
-1, NULL, 0, NULL);
/* Map the shared file. */
if (mmap(dev->mem, getpagesize(), PROT_READ|PROT_WRITE,
MAP_FIXED|MAP_SHARED, netfd, 0) != dev->mem)
err(1, "could not mmap '%s'", filename);
verbose("device %p: shared net %s, peer %i\n",
(void *)(dev->desc->pfn * getpagesize()), filename,
dev->desc->features & ~LGUEST_NET_F_NOCSUM);
}
/*:*/
* Faster is to do virtio bonding in kernel. Doing this 1:1 would be
* completely generic ("here's my vring, attach to your vring") and would work
* for any traffic. Of course, namespace and permissions issues need to be
* dealt with. A more sophisticated "multi-channel" virtio_net.c could hide
* multiple inter-guest channels behind one interface, although it would
* require some manner of hotplugging new virtio channels.
*
* Finally, we could implement a virtio network switch in the kernel. :*/
static u32 str2ip(const char *ipaddr)
{
......@@ -1188,7 +1214,7 @@ static void add_to_bridge(int fd, const char *if_name, const char *br_name)
/* This sets up the Host end of the network device with an IP address, brings
* it up so packets will flow, the copies the MAC address into the hwaddr
* pointer (in practice, the Host's slot in the network device's memory). */
* pointer. */
static void configure_device(int fd, const char *devname, u32 ipaddr,
unsigned char hwaddr[6])
{
......@@ -1214,18 +1240,18 @@ static void configure_device(int fd, const char *devname, u32 ipaddr,
memcpy(hwaddr, ifr.ifr_hwaddr.sa_data, 6);
}
/*L:195 The other kind of network is a Host<->Guest network. This can either
* use briding or routing, but the principle is the same: it uses the "tun"
* device to inject packets into the Host as if they came in from a normal
* network card. We just shunt packets between the Guest and the tun
* device. */
static void setup_tun_net(const char *arg, struct device_list *devices)
/*L:195 Our network is a Host<->Guest network. This can either use bridging or
* routing, but the principle is the same: it uses the "tun" device to inject
* packets into the Host as if they came in from a normal network card. We
* just shunt packets between the Guest and the tun device. */
static void setup_tun_net(const char *arg)
{
struct device *dev;
struct ifreq ifr;
int netfd, ipfd;
u32 ip;
const char *br_name = NULL;
u8 hwaddr[6];
/* 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
......@@ -1241,21 +1267,12 @@ static void setup_tun_net(const char *arg, struct device_list *devices)
* device: trust us! */
ioctl(netfd, TUNSETNOCSUM, 1);
/* We create the net device with 1 page, using the features field of
* the descriptor to tell the Guest it is in slot 1 (NET_PEERNUM), and
* that the device has fairly random timing. We do *not* specify
* LGUEST_NET_F_NOCSUM: these packets can reach the real world.
*
* We will put our MAC address is slot 0 for the Guest to see, so
* it will send packets to us using the key "peer_offset(0)": */
dev = new_device(devices, LGUEST_DEVICE_T_NET, 1,
NET_PEERNUM|LGUEST_DEVICE_F_RANDOMNESS, netfd,
handle_tun_input, peer_offset(0), handle_tun_output);
/* First we create a new network device. */
dev = new_device("net", VIRTIO_ID_NET, netfd, handle_tun_input);
/* We keep a flag which says whether we've seen packets come out from
* this network device. */
dev->priv = malloc(sizeof(bool));
*(bool *)dev->priv = false;
/* Network devices need a receive and a send queue. */
add_virtqueue(dev, VIRTQUEUE_NUM, NULL);
add_virtqueue(dev, VIRTQUEUE_NUM, handle_net_output);
/* We need a socket to perform the magic network ioctls to bring up the
* tap interface, connect to the bridge etc. Any socket will do! */
......@@ -1271,44 +1288,251 @@ static void setup_tun_net(const char *arg, struct device_list *devices)
} else /* It is an IP address to set up the device with */
ip = str2ip(arg);
/* We are peer 0, ie. first slot, so we hand dev->mem to this routine
* to write the MAC address at the start of the device memory. */
configure_device(ipfd, ifr.ifr_name, ip, dev->mem);
/* Set up the tun device, and get the mac address for the interface. */
configure_device(ipfd, ifr.ifr_name, ip, hwaddr);
/* Set "promisc" bit: we want every single packet if we're going to
* bridge to other machines (and otherwise it doesn't matter). */
*((u8 *)dev->mem) |= 0x1;
/* Tell Guest what MAC address to use. */
add_desc_field(dev, VIRTIO_CONFIG_NET_MAC_F, sizeof(hwaddr), hwaddr);
/* We don't seed the socket any more; setup is done. */
close(ipfd);
verbose("device %p: tun net %u.%u.%u.%u\n",
(void *)(dev->desc->pfn * getpagesize()),
(u8)(ip>>24), (u8)(ip>>16), (u8)(ip>>8), (u8)ip);
verbose("device %u: tun net %u.%u.%u.%u\n",
devices.device_num++,
(u8)(ip>>24),(u8)(ip>>16),(u8)(ip>>8),(u8)ip);
if (br_name)
verbose("attached to bridge: %s\n", br_name);
}
/*
* Block device.
*
* Serving a block device is really easy: the Guest asks for a block number and
* we read or write that position in the file.
*
* Unfortunately, this is amazingly slow: the Guest waits until the read is
* finished before running anything else, even if it could be doing useful
* work. We could use async I/O, except it's reputed to suck so hard that
* characters actually go missing from your code when you try to use it.
*
* So we farm the I/O out to thread, and communicate with it via a pipe. */
/* This hangs off device->priv, with the data. */
struct vblk_info
{
/* The size of the file. */
off64_t len;
/* The file descriptor for the file. */
int fd;
/* IO thread listens on this file descriptor [0]. */
int workpipe[2];
/* IO thread writes to this file descriptor to mark it done, then
* Launcher triggers interrupt to Guest. */
int done_fd;
};
/* This is the core of the I/O thread. It returns true if it did something. */
static bool service_io(struct device *dev)
{
struct vblk_info *vblk = dev->priv;
unsigned int head, out_num, in_num, wlen;
int ret;
struct virtio_blk_inhdr *in;
struct virtio_blk_outhdr *out;
struct iovec iov[dev->vq->vring.num];
off64_t off;
head = get_vq_desc(dev->vq, iov, &out_num, &in_num);
if (head == dev->vq->vring.num)
return false;
if (out_num == 0 || in_num == 0)
errx(1, "Bad virtblk cmd %u out=%u in=%u",
head, out_num, in_num);
out = convert(&iov[0], struct virtio_blk_outhdr);
in = convert(&iov[out_num+in_num-1], struct virtio_blk_inhdr);
off = out->sector * 512;
/* This is how we implement barriers. Pretty poor, no? */
if (out->type & VIRTIO_BLK_T_BARRIER)
fdatasync(vblk->fd);
if (out->type & VIRTIO_BLK_T_SCSI_CMD) {
fprintf(stderr, "Scsi commands unsupported\n");
in->status = VIRTIO_BLK_S_UNSUPP;
wlen = sizeof(in);
} else if (out->type & VIRTIO_BLK_T_OUT) {
/* Write */
/* Move to the right location in the block file. This can fail
* if they try to write past end. */
if (lseek64(vblk->fd, off, SEEK_SET) != off)
err(1, "Bad seek to sector %llu", out->sector);
ret = writev(vblk->fd, iov+1, out_num-1);
verbose("WRITE to sector %llu: %i\n", out->sector, ret);
/* Grr... Now we know how long the descriptor they sent was, we
* make sure they didn't try to write over the end of the block
* file (possibly extending it). */
if (ret > 0 && off + ret > vblk->len) {
/* Trim it back to the correct length */
ftruncate64(vblk->fd, vblk->len);
/* Die, bad Guest, die. */
errx(1, "Write past end %llu+%u", off, ret);
}
wlen = sizeof(in);
in->status = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);
} else {
/* Read */
/* Move to the right location in the block file. This can fail
* if they try to read past end. */
if (lseek64(vblk->fd, off, SEEK_SET) != off)
err(1, "Bad seek to sector %llu", out->sector);
ret = readv(vblk->fd, iov+1, in_num-1);
verbose("READ from sector %llu: %i\n", out->sector, ret);
if (ret >= 0) {
wlen = sizeof(in) + ret;
in->status = VIRTIO_BLK_S_OK;
} else {
wlen = sizeof(in);
in->status = VIRTIO_BLK_S_IOERR;
}
}
/* We can't trigger an IRQ, because we're not the Launcher. It does
* that when we tell it we're done. */
add_used(dev->vq, head, wlen);
return true;
}
/* This is the thread which actually services the I/O. */
static int io_thread(void *_dev)
{
struct device *dev = _dev;
struct vblk_info *vblk = dev->priv;
char c;
/* Close other side of workpipe so we get 0 read when main dies. */
close(vblk->workpipe[1]);
/* Close the other side of the done_fd pipe. */
close(dev->fd);
/* When this read fails, it means Launcher died, so we follow. */
while (read(vblk->workpipe[0], &c, 1) == 1) {
/* We acknowledge each request immediately, to reduce latency,
* rather than waiting until we've done them all. I haven't
* measured to see if it makes any difference. */
while (service_io(dev))
write(vblk->done_fd, &c, 1);
}
return 0;
}
/* When the thread says some I/O is done, we interrupt the Guest. */
static bool handle_io_finish(int fd, struct device *dev)
{
char c;
/* If child died, presumably it printed message. */
if (read(dev->fd, &c, 1) != 1)
exit(1);
/* It did some work, so trigger the irq. */
trigger_irq(fd, dev->vq);
return true;
}
/* When the Guest submits some I/O, we wake the I/O thread. */
static void handle_virtblk_output(int fd, struct virtqueue *vq)
{
struct vblk_info *vblk = vq->dev->priv;
char c = 0;
/* Wake up I/O thread and tell it to go to work! */
if (write(vblk->workpipe[1], &c, 1) != 1)
/* Presumably it indicated why it died. */
exit(1);
}
/* This creates a virtual block device. */
static void setup_block_file(const char *filename)
{
int p[2];
struct device *dev;
struct vblk_info *vblk;
void *stack;
u64 cap;
unsigned int val;
/* This is the pipe the I/O thread will use to tell us I/O is done. */
pipe(p);
/* The device responds to return from I/O thread. */
dev = new_device("block", VIRTIO_ID_BLOCK, p[0], handle_io_finish);
/* The device has a virtqueue. */
add_virtqueue(dev, VIRTQUEUE_NUM, handle_virtblk_output);
/* Allocate the room for our own bookkeeping */
vblk = dev->priv = malloc(sizeof(*vblk));
/* First we open the file and store the length. */
vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE);
vblk->len = lseek64(vblk->fd, 0, SEEK_END);
/* 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);
/* 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);
/* The I/O thread writes to this end of the pipe when done. */
vblk->done_fd = p[1];
/* This is how we tell the I/O thread about more work. */
pipe(vblk->workpipe);
/* Create stack for thread and run it */
stack = malloc(32768);
if (clone(io_thread, stack + 32768, CLONE_VM, dev) == -1)
err(1, "Creating clone");
/* We don't need to keep the I/O thread's end of the pipes open. */
close(vblk->done_fd);
close(vblk->workpipe[0]);
verbose("device %u: virtblock %llu sectors\n",
devices.device_num, cap);
}
/* 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. */
static void __attribute__((noreturn))
run_guest(int lguest_fd, struct device_list *device_list)
static void __attribute__((noreturn)) run_guest(int lguest_fd)
{
for (;;) {
unsigned long args[] = { LHREQ_BREAK, 0 };
unsigned long arr[2];
unsigned long notify_addr;
int readval;
/* We read from the /dev/lguest device to run the Guest. */
readval = read(lguest_fd, arr, sizeof(arr));
readval = read(lguest_fd, &notify_addr, sizeof(notify_addr));
/* The read can only really return sizeof(arr) (the Guest did a
* SEND_DMA to us), or an error. */
/* For a successful read, arr[0] is the address of the "struct
* lguest_dma", and arr[1] is the key the Guest sent to. */
if (readval == sizeof(arr)) {
handle_output(lguest_fd, arr[0], arr[1], device_list);
/* One unsigned long means the Guest did HCALL_NOTIFY */
if (readval == sizeof(notify_addr)) {
verbose("Notify on address %#lx\n", notify_addr);
handle_output(lguest_fd, notify_addr);
continue;
/* ENOENT means the Guest died. Reading tells us why. */
} else if (errno == ENOENT) {
......@@ -1322,7 +1546,7 @@ run_guest(int lguest_fd, struct device_list *device_list)
/* Service input, then unset the BREAK which releases
* the Waker. */
handle_input(lguest_fd, device_list);
handle_input(lguest_fd);
if (write(lguest_fd, args, sizeof(args)) < 0)
err(1, "Resetting break");
}
......@@ -1336,7 +1560,6 @@ run_guest(int lguest_fd, struct device_list *device_list)
static struct option opts[] = {
{ "verbose", 0, NULL, 'v' },
{ "sharenet", 1, NULL, 's' },
{ "tunnet", 1, NULL, 't' },
{ "block", 1, NULL, 'b' },
{ "initrd", 1, NULL, 'i' },
......@@ -1345,7 +1568,7 @@ static struct option opts[] = {
static void usage(void)
{
errx(1, "Usage: lguest [--verbose] "
"[--sharenet=<filename>|--tunnet=(<ipaddr>|bridge:<bridgename>)\n"
"[--tunnet=(<ipaddr>|bridge:<bridgename>)\n"
"|--block=<filename>|--initrd=<filename>]...\n"
"<mem-in-mb> vmlinux [args...]");
}
......@@ -1358,8 +1581,6 @@ int main(int argc, char *argv[])
unsigned long mem = 0, pgdir, start, initrd_size = 0;
/* A temporary and the /dev/lguest file descriptor. */
int i, c, lguest_fd;
/* The list of Guest devices, based on command line arguments. */
struct device_list device_list;
/* The boot information for the Guest. */
void *boot;
/* If they specify an initrd file to load. */
......@@ -1369,11 +1590,12 @@ int main(int argc, char *argv[])
* 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. */
device_list.max_infd = -1;
device_list.dev = NULL;
device_list.lastdev = &device_list.dev;
FD_ZERO(&device_list.infds);
* to the list. 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.next_irq = 1;
/* 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
......@@ -1390,7 +1612,7 @@ int main(int argc, char *argv[])
+ DEVICE_PAGES);
guest_limit = mem;
guest_max = mem + DEVICE_PAGES*getpagesize();
device_list.descs = get_pages(1);
devices.descpage = get_pages(1);
break;
}
}
......@@ -1401,14 +1623,11 @@ int main(int argc, char *argv[])
case 'v':
verbose = true;
break;
case 's':
setup_net_file(optarg, &device_list);
break;
case 't':
setup_tun_net(optarg, &device_list);
setup_tun_net(optarg);
break;
case 'b':
setup_block_file(optarg, &device_list);
setup_block_file(optarg);
break;
case 'i':
initrd_name = optarg;
......@@ -1426,7 +1645,7 @@ int main(int argc, char *argv[])
verbose("Guest base is at %p\n", guest_base);
/* We always have a console device */
setup_console(&device_list);
setup_console();
/* Now we load the kernel */
start = load_kernel(open_or_die(argv[optind+1], O_RDONLY));
......@@ -1468,10 +1687,10 @@ int main(int argc, char *argv[])
/* We fork off a child process, which wakes the Launcher whenever one
* of the input file descriptors needs attention. Otherwise we would
* run the Guest until it tries to output something. */
waker_fd = setup_waker(lguest_fd, &device_list);
waker_fd = setup_waker(lguest_fd);
/* Finally, run the Guest. This doesn't return. */
run_guest(lguest_fd, &device_list);
run_guest(lguest_fd);
}
/*:*/
......
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