lguest: cleanup passing of /dev/lguest fd around example launcher.
We hand the /dev/lguest fd everywhere; it's far neater to just make it a global (it already is, in fact, hidden in the waker_fds struct). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
parent
713b15b378
commit
56739c802c
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@ -79,7 +79,6 @@ static bool verbose;
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/* File descriptors for the Waker. */
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struct {
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int pipe[2];
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int lguest_fd;
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} waker_fds;
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/* The pointer to the start of guest memory. */
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@ -89,6 +88,8 @@ static unsigned long guest_limit, guest_max;
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/* The pipe for signal hander to write to. */
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static int timeoutpipe[2];
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static unsigned int timeout_usec = 500;
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/* The /dev/lguest file descriptor. */
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static int lguest_fd;
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/* a per-cpu variable indicating whose vcpu is currently running */
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static unsigned int __thread cpu_id;
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@ -139,7 +140,7 @@ struct device
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/* If handle_input is set, it wants to be called when this file
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* descriptor is ready. */
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int fd;
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bool (*handle_input)(int fd, struct device *me);
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bool (*handle_input)(struct device *me);
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/* Any queues attached to this device */
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struct virtqueue *vq;
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@ -169,7 +170,7 @@ struct virtqueue
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u16 last_avail_idx;
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/* The routine to call when the Guest pings us, or timeout. */
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void (*handle_output)(int fd, struct virtqueue *me, bool timeout);
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void (*handle_output)(struct virtqueue *me, bool timeout);
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/* Outstanding buffers */
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unsigned int inflight;
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@ -509,21 +510,16 @@ static void concat(char *dst, char *args[])
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* saw the arguments it expects when we looked at initialize() in lguest_user.c:
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* the base of Guest "physical" memory, the top physical page to allow and the
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* entry point for the Guest. */
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static int tell_kernel(unsigned long start)
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static void tell_kernel(unsigned long start)
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{
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unsigned long args[] = { LHREQ_INITIALIZE,
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(unsigned long)guest_base,
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guest_limit / getpagesize(), start };
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int fd;
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verbose("Guest: %p - %p (%#lx)\n",
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guest_base, guest_base + guest_limit, guest_limit);
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fd = open_or_die("/dev/lguest", O_RDWR);
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if (write(fd, args, sizeof(args)) < 0)
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lguest_fd = open_or_die("/dev/lguest", O_RDWR);
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if (write(lguest_fd, args, sizeof(args)) < 0)
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err(1, "Writing to /dev/lguest");
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/* We return the /dev/lguest file descriptor to control this Guest */
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return fd;
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}
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/*:*/
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@ -583,21 +579,18 @@ static int waker(void *unused)
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}
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/* Send LHREQ_BREAK command to snap the Launcher out of it. */
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pwrite(waker_fds.lguest_fd, args, sizeof(args), cpu_id);
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pwrite(lguest_fd, args, sizeof(args), cpu_id);
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}
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return 0;
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}
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/* This routine just sets up a pipe to the Waker process. */
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static void setup_waker(int lguest_fd)
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static void setup_waker(void)
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{
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/* This pipe is closed when Launcher dies, telling Waker. */
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if (pipe(waker_fds.pipe) != 0)
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err(1, "Creating pipe for Waker");
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/* Waker also needs to know the lguest fd */
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waker_fds.lguest_fd = lguest_fd;
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if (clone(waker, malloc(4096) + 4096, CLONE_VM | SIGCHLD, NULL) == -1)
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err(1, "Creating Waker");
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}
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@ -727,7 +720,7 @@ static void add_used(struct virtqueue *vq, unsigned int head, int len)
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}
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/* This actually sends the interrupt for this virtqueue */
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static void trigger_irq(int fd, struct virtqueue *vq)
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static void trigger_irq(struct virtqueue *vq)
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{
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unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
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@ -737,16 +730,15 @@ static void trigger_irq(int fd, struct virtqueue *vq)
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return;
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/* Send the Guest an interrupt tell them we used something up. */
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if (write(fd, buf, sizeof(buf)) != 0)
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if (write(lguest_fd, buf, sizeof(buf)) != 0)
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err(1, "Triggering irq %i", vq->config.irq);
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}
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/* And here's the combo meal deal. Supersize me! */
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static void add_used_and_trigger(int fd, struct virtqueue *vq,
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unsigned int head, int len)
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static void add_used_and_trigger(struct virtqueue *vq, unsigned head, int len)
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{
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add_used(vq, head, len);
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trigger_irq(fd, vq);
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trigger_irq(vq);
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}
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/*
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@ -770,7 +762,7 @@ struct console_abort
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};
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/* This is the routine which handles console input (ie. stdin). */
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static bool handle_console_input(int fd, struct device *dev)
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static bool handle_console_input(struct device *dev)
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{
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int len;
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unsigned int head, in_num, out_num;
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@ -804,7 +796,7 @@ static bool handle_console_input(int fd, struct device *dev)
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}
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/* Tell the Guest about the new input. */
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add_used_and_trigger(fd, dev->vq, head, len);
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add_used_and_trigger(dev->vq, head, len);
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/* Three ^C within one second? Exit.
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*
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@ -824,7 +816,7 @@ static bool handle_console_input(int fd, struct device *dev)
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close(waker_fds.pipe[1]);
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/* Just in case Waker is blocked in BREAK, send
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* unbreak now. */
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write(fd, args, sizeof(args));
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write(lguest_fd, args, sizeof(args));
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exit(2);
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}
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abort->count = 0;
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@ -839,7 +831,7 @@ static bool handle_console_input(int fd, struct device *dev)
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/* Handling output for console is simple: we just get all the output buffers
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* and write them to stdout. */
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static void handle_console_output(int fd, struct virtqueue *vq, bool timeout)
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static void handle_console_output(struct virtqueue *vq, bool timeout)
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{
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unsigned int head, out, in;
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int len;
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@ -850,7 +842,7 @@ static void handle_console_output(int fd, struct virtqueue *vq, bool timeout)
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if (in)
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errx(1, "Input buffers in output queue?");
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len = writev(STDOUT_FILENO, iov, out);
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add_used_and_trigger(fd, vq, head, len);
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add_used_and_trigger(vq, head, len);
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}
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}
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@ -879,7 +871,7 @@ static void block_vq(struct virtqueue *vq)
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* and write them (ignoring the first element) to this device's file descriptor
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* (/dev/net/tun).
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*/
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static void handle_net_output(int fd, struct virtqueue *vq, bool timeout)
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static void handle_net_output(struct virtqueue *vq, bool timeout)
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{
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unsigned int head, out, in, num = 0;
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int len;
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@ -893,7 +885,7 @@ static void handle_net_output(int fd, struct virtqueue *vq, bool timeout)
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len = writev(vq->dev->fd, iov, out);
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if (len < 0)
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err(1, "Writing network packet to tun");
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add_used_and_trigger(fd, vq, head, len);
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add_used_and_trigger(vq, head, len);
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num++;
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}
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@ -917,7 +909,7 @@ static void handle_net_output(int fd, struct virtqueue *vq, bool timeout)
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/* This is where we handle a packet coming in from the tun device to our
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* Guest. */
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static bool handle_tun_input(int fd, struct device *dev)
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static bool handle_tun_input(struct device *dev)
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{
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unsigned int head, in_num, out_num;
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int len;
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@ -946,7 +938,7 @@ static bool handle_tun_input(int fd, struct device *dev)
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err(1, "reading network");
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/* Tell the Guest about the new packet. */
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add_used_and_trigger(fd, dev->vq, head, len);
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add_used_and_trigger(dev->vq, head, len);
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verbose("tun input packet len %i [%02x %02x] (%s)\n", len,
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((u8 *)iov[1].iov_base)[0], ((u8 *)iov[1].iov_base)[1],
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@ -959,18 +951,18 @@ static bool handle_tun_input(int fd, struct device *dev)
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/*L:215 This is the callback attached to the network and console input
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* virtqueues: it ensures we try again, in case we stopped console or net
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* delivery because Guest didn't have any buffers. */
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static void enable_fd(int fd, struct virtqueue *vq, bool timeout)
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static void enable_fd(struct virtqueue *vq, bool timeout)
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{
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add_device_fd(vq->dev->fd);
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/* Snap the Waker out of its select loop. */
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write(waker_fds.pipe[1], "", 1);
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}
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static void net_enable_fd(int fd, struct virtqueue *vq, bool timeout)
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static void net_enable_fd(struct virtqueue *vq, bool timeout)
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{
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/* We don't need to know again when Guest refills receive buffer. */
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vq->vring.used->flags |= VRING_USED_F_NO_NOTIFY;
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enable_fd(fd, vq, timeout);
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enable_fd(vq, timeout);
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}
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/* When the Guest tells us they updated the status field, we handle it. */
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@ -1011,7 +1003,7 @@ static void update_device_status(struct device *dev)
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}
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/* This is the generic routine we call when the Guest uses LHCALL_NOTIFY. */
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static void handle_output(int fd, unsigned long addr)
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static void handle_output(unsigned long addr)
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{
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struct device *i;
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struct virtqueue *vq;
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@ -1039,7 +1031,7 @@ static void handle_output(int fd, unsigned long addr)
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if (strcmp(vq->dev->name, "console") != 0)
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verbose("Output to %s\n", vq->dev->name);
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if (vq->handle_output)
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vq->handle_output(fd, vq, false);
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vq->handle_output(vq, false);
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return;
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}
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}
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@ -1053,7 +1045,7 @@ static void handle_output(int fd, unsigned long addr)
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strnlen(from_guest_phys(addr), guest_limit - addr));
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}
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static void handle_timeout(int fd)
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static void handle_timeout(void)
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{
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char buf[32];
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struct device *i;
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@ -1071,14 +1063,14 @@ static void handle_timeout(int fd)
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vq->vring.used->flags &= ~VRING_USED_F_NO_NOTIFY;
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vq->blocked = false;
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if (vq->handle_output)
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vq->handle_output(fd, vq, true);
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vq->handle_output(vq, true);
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}
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}
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}
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/* This is called when the Waker wakes us up: check for incoming file
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* descriptors. */
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static void handle_input(int fd)
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static void handle_input(void)
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{
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/* select() wants a zeroed timeval to mean "don't wait". */
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struct timeval poll = { .tv_sec = 0, .tv_usec = 0 };
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@ -1100,7 +1092,7 @@ static void handle_input(int fd)
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* descriptors and a method of handling them. */
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for (i = devices.dev; i; i = i->next) {
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if (i->handle_input && FD_ISSET(i->fd, &fds)) {
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if (i->handle_input(fd, i))
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if (i->handle_input(i))
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continue;
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/* If handle_input() returns false, it means we
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@ -1114,7 +1106,7 @@ static void handle_input(int fd)
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/* Is this the timeout fd? */
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if (FD_ISSET(timeoutpipe[0], &fds))
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handle_timeout(fd);
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handle_timeout();
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}
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}
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@ -1163,7 +1155,7 @@ static struct lguest_device_desc *new_dev_desc(u16 type)
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/* Each device descriptor is followed by the description of its virtqueues. We
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* specify how many descriptors the virtqueue is to have. */
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static void add_virtqueue(struct device *dev, unsigned int num_descs,
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void (*handle_output)(int, struct virtqueue *, bool))
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void (*handle_output)(struct virtqueue *, bool))
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{
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unsigned int pages;
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struct virtqueue **i, *vq = malloc(sizeof(*vq));
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@ -1249,7 +1241,7 @@ static void set_config(struct device *dev, unsigned len, const void *conf)
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*
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* See what I mean about userspace being boring? */
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static struct device *new_device(const char *name, u16 type, int fd,
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bool (*handle_input)(int, struct device *))
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bool (*handle_input)(struct device *))
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{
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struct device *dev = malloc(sizeof(*dev));
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@ -1678,7 +1670,7 @@ static int io_thread(void *_dev)
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/* Now we've seen the I/O thread, we return to the Launcher to see what happens
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* when that thread tells us it's completed some I/O. */
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static bool handle_io_finish(int fd, struct device *dev)
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static bool handle_io_finish(struct device *dev)
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{
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char c;
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@ -1688,12 +1680,12 @@ static bool handle_io_finish(int fd, struct device *dev)
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exit(1);
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/* It did some work, so trigger the irq. */
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trigger_irq(fd, dev->vq);
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trigger_irq(dev->vq);
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return true;
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}
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/* When the Guest submits some I/O, we just need to wake the I/O thread. */
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static void handle_virtblk_output(int fd, struct virtqueue *vq, bool timeout)
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static void handle_virtblk_output(struct virtqueue *vq, bool timeout)
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{
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struct vblk_info *vblk = vq->dev->priv;
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char c = 0;
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@ -1771,7 +1763,7 @@ static void setup_block_file(const char *filename)
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* console is the reverse.
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*
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* The same logic applies, however. */
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static bool handle_rng_input(int fd, struct device *dev)
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static bool handle_rng_input(struct device *dev)
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{
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int len;
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unsigned int head, in_num, out_num, totlen = 0;
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@ -1800,7 +1792,7 @@ static bool handle_rng_input(int fd, struct device *dev)
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}
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/* Tell the Guest about the new input. */
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add_used_and_trigger(fd, dev->vq, head, totlen);
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add_used_and_trigger(dev->vq, head, totlen);
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/* Everything went OK! */
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return true;
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@ -1841,7 +1833,7 @@ static void __attribute__((noreturn)) restart_guest(void)
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/*L:220 Finally we reach the core of the Launcher which runs the Guest, serves
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* its input and output, and finally, lays it to rest. */
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static void __attribute__((noreturn)) run_guest(int lguest_fd)
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static void __attribute__((noreturn)) run_guest(void)
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{
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for (;;) {
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unsigned long args[] = { LHREQ_BREAK, 0 };
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@ -1855,7 +1847,7 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd)
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/* One unsigned long means the Guest did HCALL_NOTIFY */
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if (readval == sizeof(notify_addr)) {
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verbose("Notify on address %#lx\n", notify_addr);
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handle_output(lguest_fd, notify_addr);
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handle_output(notify_addr);
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continue;
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/* ENOENT means the Guest died. Reading tells us why. */
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} else if (errno == ENOENT) {
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@ -1875,7 +1867,7 @@ static void __attribute__((noreturn)) run_guest(int lguest_fd)
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continue;
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/* Service input, then unset the BREAK to release the Waker. */
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handle_input(lguest_fd);
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handle_input();
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if (pwrite(lguest_fd, args, sizeof(args), cpu_id) < 0)
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err(1, "Resetting break");
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}
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@ -1911,8 +1903,8 @@ int main(int argc, char *argv[])
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/* Memory, top-level pagetable, code startpoint and size of the
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* (optional) initrd. */
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unsigned long mem = 0, start, initrd_size = 0;
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/* Two temporaries and the /dev/lguest file descriptor. */
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int i, c, lguest_fd;
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/* Two temporaries. */
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int i, c;
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/* The boot information for the Guest. */
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struct boot_params *boot;
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/* If they specify an initrd file to load. */
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@ -2030,15 +2022,15 @@ int main(int argc, char *argv[])
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/* We tell the kernel to initialize the Guest: this returns the open
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* /dev/lguest file descriptor. */
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lguest_fd = tell_kernel(start);
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tell_kernel(start);
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/* We clone off a thread, which wakes the Launcher whenever one of the
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* input file descriptors needs attention. We call this the Waker, and
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* we'll cover it in a moment. */
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setup_waker(lguest_fd);
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setup_waker();
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/* Finally, run the Guest. This doesn't return. */
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run_guest(lguest_fd);
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run_guest();
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}
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/*:*/
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