From: Alexander Bluhm <bluhm@openbsd.org>
Subject: Re: Sysupgrade on i386 vmm to current snapshot hangs on boot into upgrade kernel
To: Brent Cook <busterb@gmail.com>
Cc: Mike Larkin <mlarkin@nested.page>, tech@openbsd.org
Date: Tue, 7 Apr 2026 11:35:57 +0200

I am running this diff for two days in my automatic setup.
Alpine Linux, OpenBSD amd64 and OpenBSD i386 work.

bluhm

On Sun, Apr 05, 2026 at 01:08:51PM -0500, Brent Cook wrote:
> diff --git a/usr.sbin/vmd/i8253.c b/usr.sbin/vmd/i8253.c
> index 9e32d9382b6..091716a2f32 100644
> --- a/usr.sbin/vmd/i8253.c
> +++ b/usr.sbin/vmd/i8253.c
> @@ -262,12 +262,14 @@ vcpu_exit_i8253(struct vm_run_params *vrp)
>  					    ticks % i8253_channel[sel].start;
>  				} else
>  					i8253_channel[sel].olatch = 0;
> +				i8253_channel[sel].last_r = 2;
>  				goto ret;
>  			} else if (rw != TIMER_16BIT) {
>  				log_warnx("%s: i8253 PIT: unsupported counter "
>  				    "%d rw mode 0x%x selected", __func__,
>  				    sel, (rw & TIMER_16BIT));
>  			}
> +			i8253_channel[sel].last_w = 0;
>  			i8253_channel[sel].mode = (out_data & 0xe) >> 1;
>  
>  			goto ret;
> @@ -293,6 +295,9 @@ vcpu_exit_i8253(struct vm_run_params *vrp)
>  				if (i8253_channel[sel].start == 0)
>  					i8253_channel[sel].start = 0xffff;
>  
> +				clock_gettime(CLOCK_MONOTONIC,
> +				    &i8253_channel[sel].ts);
> +
>  				DPRINTF("%s: channel %d reset, mode=%d, "
>  				    "start=%d\n", __func__,
>  				    sel, i8253_channel[sel].mode,
>