Skip to content

console_quiet=1: drop user space's console output (default under avfboot) #24

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
dylanneve1 merged 1 commit into from
Oct 23, 2026
Merged

console_quiet=1: drop user space's console output (default under avfboot) #24

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 6 additions & 0 deletions avf/shim/avfboot.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -809,6 +809,12 @@ void avfboot_main(uint64_t fdt_pa)
if (!has_arg(pi.cmdline, "cpus=") && !has_arg(pi.cmdline, "cpumask=") &&
!has_arg(m.bootargs, "cpus=") && !has_arg(m.bootargs, "cpumask="))
cmd_append(cl, &n, "cpus=1 ");
/*
* User space quiet on the console unless asked otherwise (console_quiet=0): every console byte
* is a trap to crosvm, and launchd alone writes thousands of lines a minute (patch 1003).
*/
if (!has_arg(pi.cmdline, "console_quiet=") && !has_arg(m.bootargs, "console_quiet="))
cmd_append(cl, &n, "console_quiet=1 ");
if (rd_size && !has_arg(pi.cmdline, "rd=") && !has_arg(m.bootargs, "rd="))
cmd_append(cl, &n, "rd=md0 ");
cmd_append(cl, &n, pi.cmdline);
Expand Down
28 changes: 28 additions & 0 deletions xnu/patches/1003-avf-console-quiet.patch
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
diff --git a/bsd/dev/arm/km.c b/bsd/dev/arm/km.c
index 69eacee..9e244fc 100644
--- a/bsd/dev/arm/km.c
+++ b/bsd/dev/arm/km.c
@@ -175,6 +175,23 @@ kmwrite(dev_t dev, struct uio * uio, int ioflag)
int ret;
struct tty *tp = km_tty[minor(dev)];

+ /*
+ * Boot-arg console_quiet=1: what user space writes to the console (launchd's own log, the
+ * daemons' standard error, os_log mirrored there) is dropped; the kernel's printf and panics
+ * are not written this way and still come out. Under a hypervisor every console byte is a
+ * trap to the VMM: on the Pixel (AVF), launchd's log of SpringBoard's failed lookups kept the
+ * host's console thread a quarter busy.
+ */
+ static int quiet = -1;
+ if (quiet < 0) {
+ uint32_t v = 0;
+ quiet = PE_parse_boot_argn("console_quiet", &v, sizeof(v)) && v != 0;
+ }
+ if (quiet) {
+ uio_update(uio, uio_resid(uio));
+ return 0;
+ }
+
tty_lock(tp);
ret = (*linesw[tp->t_line].l_write)(tp, uio, ioflag);
tty_unlock(tp);
Loading