Klemens Nanni <k...@openbsd.org> writes:
> On Sun, Oct 15, 2023 at 07:51:00AM -0400, Dave Voutila wrote: >> >> Dave Voutila <d...@sisu.io> writes: >> >> > Looking for folks that use the serial console connection in vmd(8) and >> > experience the host CPU spikes & delays associated with things like >> > hitting the up key (to cycle shell command history) or copy/paste in X. >> > >> > vmd(8) approximates edge triggered interrupts with the emulated i8259 >> > interrupt controller. Some core devices (serial console, rtc, timer) try >> > "toggling" an irq...but it's pointless in how our emulated i8259 is >> > implemented. The deassert does nothing for edge triggered interrupts >> > other than causing race conditions and extra syscalls. >> > >> > I've tested on two of my machines and this resolves the issue I've been >> > seeing off and on. It should fix the report[1] on bugs@ from months ago. >> >> Still looking for testers as the origin bug reporter has not responded. > > I know and saw that typing certain things or pasting into the serial > console had really annoying issues, but now during tests I failed to > reproduce this, with or without your diff. Some of my recent fixes probably reduced the probability of hitting the race condition. > > Interacting wth OpenBSD and Alpine Linux guests via 'vmctl console' works > fine for me with this diff. > That's good news. Thanks. >> >> > >> > -dv >> > >> > [1] https://marc.info/?l=openbsd-bugs&m=169669132915760&w=2 >> > >> > diff refs/heads/master refs/heads/vmd-edge >> > commit - 7869b2fdaac7e118bfd1783874fe25ce3b8b0f09 >> > commit + 00d448cdbe2461f27419aaf79520a0cef720aefc >> > blob - b98e7bdc69ac6a12eb84eaaf97ec43ecdbe83733 >> > blob + 248e3b161e88be505a88411156dc57a2772bd4fa >> > --- usr.sbin/vmd/i8253.c >> > +++ usr.sbin/vmd/i8253.c >> > @@ -371,7 +371,6 @@ i8253_fire(int fd, short type, void *arg) >> > struct i8253_channel *ctr = (struct i8253_channel *)arg; >> > >> > vcpu_assert_pic_irq(ctr->vm_id, 0, 0); >> > - vcpu_deassert_pic_irq(ctr->vm_id, 0, 0); >> > >> > if (ctr->mode != TIMER_INTTC) { >> > timerclear(&tv); >> > blob - 43dce7b10d1467a5b7ac7f3308d01e32b4d0b9ee >> > blob + 4fc147b19c99627e386ab26355b8f90a6ae5872b >> > --- usr.sbin/vmd/mc146818.c >> > +++ usr.sbin/vmd/mc146818.c >> > @@ -150,7 +150,6 @@ rtc_fireper(int fd, short type, void *arg) >> > rtc.regs[MC_REGC] |= MC_REGC_PF; >> > >> > vcpu_assert_pic_irq((ptrdiff_t)arg, 0, 8); >> > - vcpu_deassert_pic_irq((ptrdiff_t)arg, 0, 8); >> > >> > evtimer_add(&rtc.per, &rtc.per_tv); >> > } >> > blob - bc23876bf0392312335da0d00e143583a87549af >> > blob + 98ed7dbecf2120ccbf9a16198ee479cb15aebc5f >> > --- usr.sbin/vmd/ns8250.c >> > +++ usr.sbin/vmd/ns8250.c >> > @@ -82,7 +82,6 @@ ratelimit(int fd, short type, void *arg) >> > com1_dev.regs.iir &= ~IIR_NOPEND; >> > >> > vcpu_assert_pic_irq(com1_dev.vmid, 0, com1_dev.irq); >> > - vcpu_deassert_pic_irq(com1_dev.vmid, 0, com1_dev.irq); >> > mutex_unlock(&com1_dev.mutex); >> > } >> > >> > @@ -160,7 +159,6 @@ com_rcv_event(int fd, short kind, void *arg) >> > if ((com1_dev.regs.iir & IIR_NOPEND) == 0) { >> > /* XXX: vcpu_id */ >> > vcpu_assert_pic_irq((uintptr_t)arg, 0, com1_dev.irq); >> > - vcpu_deassert_pic_irq((uintptr_t)arg, 0, com1_dev.irq); >> > } >> > >> > mutex_unlock(&com1_dev.mutex); >>
