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-rw-r--r--Documentation/virtual/lguest/lguest.c47
1 files changed, 16 insertions, 31 deletions
diff --git a/Documentation/virtual/lguest/lguest.c b/Documentation/virtual/lguest/lguest.c
index cd9d6af61d0..043bd7df313 100644
--- a/Documentation/virtual/lguest/lguest.c
+++ b/Documentation/virtual/lguest/lguest.c
@@ -51,7 +51,7 @@
#include <asm/bootparam.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 */
@@ -861,8 +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);
}
@@ -898,7 +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
@@ -955,7 +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
@@ -1093,9 +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);
}
}
@@ -1120,25 +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);
}
}
@@ -1370,7 +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
@@ -1380,7 +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)
@@ -2017,10 +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. */