lguest: support emerg_wr in console device in example launcher.
This is a magic register which causes a character to be outputted: it can
be used even before the device is configured.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c
index b5ac735..8959ac2 100644
--- a/tools/lguest/lguest.c
+++ b/tools/lguest/lguest.c
@@ -71,7 +71,7 @@
#include "../../include/uapi/linux/virtio_config.h"
#include "../../include/uapi/linux/virtio_net.h"
#include "../../include/uapi/linux/virtio_blk.h"
-#include <linux/virtio_console.h>
+#include "../../include/uapi/linux/virtio_console.h"
#include "../../include/uapi/linux/virtio_rng.h"
#include <linux/virtio_ring.h>
#include "../../include/uapi/linux/virtio_pci.h"
@@ -1687,6 +1687,15 @@
goto write_through16;
case offsetof(struct virtio_pci_mmio, isr):
errx(1, "%s: Unexpected write to isr", d->name);
+ /* Weird corner case: write to emerg_wr of console */
+ case sizeof(struct virtio_pci_mmio)
+ + offsetof(struct virtio_console_config, emerg_wr):
+ if (strcmp(d->name, "console") == 0) {
+ char c = val;
+ write(STDOUT_FILENO, &c, 1);
+ goto write_through32;
+ }
+ /* Fall through... */
default:
errx(1, "%s: Unexpected write to offset %u", d->name, off);
}
@@ -2048,6 +2057,7 @@
static void setup_console(void)
{
struct device *dev;
+ struct virtio_console_config conf;
/* If we can save the initial standard input settings... */
if (tcgetattr(STDIN_FILENO, &orig_term) == 0) {
@@ -2075,8 +2085,9 @@
add_pci_virtqueue(dev, console_input);
add_pci_virtqueue(dev, console_output);
- /* There's no configuration area for this device. */
- no_device_config(dev);
+ /* We need a configuration area for the emerg_wr early writes. */
+ add_pci_feature(dev, VIRTIO_CONSOLE_F_EMERG_WRITE);
+ set_device_config(dev, &conf, sizeof(conf));
verbose("device %u: console\n", devices.device_num);
}