Peter Maydell <peter.mayd...@linaro.org> writes: > On Thu, 29 Feb 2024 at 16:54, Sven Schnelle <sv...@stackframe.org> wrote: >> >> Peter Maydell <peter.mayd...@linaro.org> writes: >> >> > On Wed, 28 Feb 2024 at 21:12, Sven Schnelle <sv...@stackframe.org> wrote: >> >> >> >> HP-UX 10.20 seems to make the lsi53c895a spinning on a memory location >> >> under certain circumstances. As the SCSI controller and CPU are not >> >> running at the same time this loop will never finish. After some >> >> time, the check loop interrupts with a unexpected device disconnect. >> >> This works, but is slow because the kernel resets the scsi controller. >> >> Instead of signaling UDC, add an option 'hpux-spin-workaround' which >> >> emulates a INTERRUPT 2 script instruction. This instruction tells the >> >> kernel that the request was fulfilled. With this change, SCSI speeds >> >> improves significantly. >> >> [..] >> > I see we already have a hacky workaround for other OSes >> > that do something similar. The ideal fix for both of these >> > I think would be for lsi_execute_script() to, instead of stopping, >> > arrange to defer executing more script instructions until >> > after the guest has had a chance to run a bit more. >> > I think setting a timer that calls lsi_resume_script() after >> > a while would have that effect. >> >> Thanks, good idea. So something like this? > > Yeah, something like that I think. (You probably want to delete > the timer on reset, and you need to handle migration -- you can > either put the timer state in a new vmstate section, or else > in post-load if the state is 'LSI_WAIT_SCRIPTS' arm the timer.)
> Does it work? :-) Yes it does. I only did a quick hack without caring about things like reset, freeing the timer and migration. I successfully booted HP-UX 10.20 without any scsi errors in the dmesg. So i think this is much better than the commandline option. I'll prepare a proper patch in the next days and submit it. Thanks! Sven
