diff options
Diffstat (limited to 'Documentation/virtual/lguest/lguest.c')
| -rw-r--r-- | Documentation/virtual/lguest/lguest.c | 69 |
1 files changed, 18 insertions, 51 deletions
diff --git a/Documentation/virtual/lguest/lguest.c b/Documentation/virtual/lguest/lguest.c index d9da7e148538..043bd7df3139 100644 --- a/Documentation/virtual/lguest/lguest.c +++ b/Documentation/virtual/lguest/lguest.c @@ -49,9 +49,9 @@ #include <linux/virtio_rng.h> #include <linux/virtio_ring.h> #include <asm/bootparam.h> -#include "../../include/linux/lguest_launcher.h" +#include "../../../include/linux/lguest_launcher.h" /*L:110 - * We can ignore the 42 include files we need for this program, but I do want + * We can ignore the 43 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 @@ -65,7 +65,6 @@ typedef uint16_t u16; typedef uint8_t u8; /*:*/ -#define PAGE_PRESENT 0x7 /* Present, RW, Execute */ #define BRIDGE_PFX "bridge:" #ifndef SIOCBRADDIF #define SIOCBRADDIF 0x89a2 /* add interface to bridge */ @@ -135,9 +134,6 @@ struct device { /* Is it operational */ bool running; - /* Does Guest want an intrrupt on empty? */ - bool irq_on_empty; - /* Device-specific data. */ void *priv; }; @@ -637,10 +633,7 @@ static void trigger_irq(struct virtqueue *vq) /* If they don't want an interrupt, don't send one... */ if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT) { - /* ... unless they've asked us to force one on empty. */ - if (!vq->dev->irq_on_empty - || lg_last_avail(vq) != vq->vring.avail->idx) - return; + return; } /* Send the Guest an interrupt tell them we used something up. */ @@ -867,8 +860,10 @@ static void console_output(struct virtqueue *vq) /* writev can return a partial write, so we loop here. */ while (!iov_empty(iov, out)) { int len = writev(STDOUT_FILENO, iov, out); - if (len <= 0) - err(1, "Write to stdout gave %i", len); + if (len <= 0) { + warn("Write to stdout gave %i (%d)", len, errno); + break; + } iov_consume(iov, out, len); } @@ -904,7 +899,7 @@ static void net_output(struct virtqueue *vq) * same format: what a coincidence! */ if (writev(net_info->tunfd, iov, out) < 0) - errx(1, "Write to tun failed?"); + warnx("Write to tun failed (%d)?", errno); /* * Done with that one; wait_for_vq_desc() will send the interrupt if @@ -961,7 +956,7 @@ static void net_input(struct virtqueue *vq) */ len = readv(net_info->tunfd, iov, in); if (len <= 0) - err(1, "Failed to read from tun."); + warn("Failed to read from tun (%d).", errno); /* * Mark that packet buffer as used, but don't interrupt here. We want @@ -1057,15 +1052,6 @@ static void create_thread(struct virtqueue *vq) close(vq->eventfd); } -static bool accepted_feature(struct device *dev, unsigned int bit) -{ - const u8 *features = get_feature_bits(dev) + dev->feature_len; - - if (dev->feature_len < bit / CHAR_BIT) - return false; - return features[bit / CHAR_BIT] & (1 << (bit % CHAR_BIT)); -} - static void start_device(struct device *dev) { unsigned int i; @@ -1079,8 +1065,6 @@ static void start_device(struct device *dev) verbose(" %02x", get_feature_bits(dev) [dev->feature_len+i]); - dev->irq_on_empty = accepted_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY); - for (vq = dev->vq; vq; vq = vq->next) { if (vq->service) create_thread(vq); @@ -1110,9 +1094,10 @@ static void update_device_status(struct device *dev) warnx("Device %s configuration FAILED", dev->name); if (dev->running) reset_device(dev); - } else if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK) { - if (!dev->running) - start_device(dev); + } else { + if (dev->running) + err(1, "Device %s features finalized twice", dev->name); + start_device(dev); } } @@ -1137,25 +1122,11 @@ static void handle_output(unsigned long addr) return; } - /* - * Devices *can* be used before status is set to DRIVER_OK. - * The original plan was that they would never do this: they - * would always finish setting up their status bits before - * actually touching the virtqueues. In practice, we allowed - * them to, and they do (eg. the disk probes for partition - * tables as part of initialization). - * - * If we see this, we start the device: once it's running, we - * expect the device to catch all the notifications. - */ + /* Devices should not be used before features are finalized. */ for (vq = i->vq; vq; vq = vq->next) { if (addr != vq->config.pfn*getpagesize()) continue; - if (i->running) - errx(1, "Notification on running %s", i->name); - /* This just calls create_thread() for each virtqueue */ - start_device(i); - return; + errx(1, "Notification on %s before setup!", i->name); } } @@ -1387,7 +1358,7 @@ static void setup_console(void) * --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. * - * More sopisticated is to use one of the tools developed for project like UML + * More sophisticated is to use one of the tools developed for project like UML * to do networking. * * Faster is to do virtio bonding in kernel. Doing this 1:1 would be @@ -1397,7 +1368,7 @@ static void setup_console(void) * 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. + * Finally, we could use a virtio network switch in the kernel, ie. vhost. :*/ static u32 str2ip(const char *ipaddr) @@ -1564,7 +1535,6 @@ static void setup_tun_net(char *arg) /* Set up the tun device. */ configure_device(ipfd, tapif, ip); - add_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY); /* Expect Guest to handle everything except UFO */ add_feature(dev, VIRTIO_NET_F_CSUM); add_feature(dev, VIRTIO_NET_F_GUEST_CSUM); @@ -2035,10 +2005,7 @@ int main(int argc, char *argv[]) /* Tell the entry path not to try to reload segment registers. */ boot->hdr.loadflags |= KEEP_SEGMENTS; - /* - * We tell the kernel to initialize the Guest: this returns the open - * /dev/lguest file descriptor. - */ + /* We tell the kernel to initialize the Guest. */ tell_kernel(start); /* Ensure that we terminate if a device-servicing child dies. */ |