On Thu, 2024-08-01 at 20:54 +0200, Thomas Gleixner wrote: > On Thu, Aug 01 2024 at 16:14, Michael Kelley wrote: > > From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Sent: Thursday, August > > 1, 2024 7:21 AM > > FWIW, in Hyper-V guests with the Hyper-V quirk removed, tglx's new > > sequence does *not* stop the PIT. But this sequence does: > > > > outb_p(0x30, PIT_MODE); > > outb_p(0xff, PIT_CH0); > > outb_p(0xff, PIT_CH0); > > > > outb_p(0x30, PIT_MODE); > > outb_p(0xff, PIT_CH0); > > That works on bare metal too What about writing *just* the MODE? The datasheet definitely seems to be saying that should work too. And I believe it works on Hyper-V; that's what the "workaround" has been doing, because Hyper-V actually got it right. > > I don't have a convenient way to test my sequence on KVM. > > But still fails in KVM By KVM you mean the in-kernel one that we want to kill because everyone should be using userspace IRQ chips these days? I don't know that we care; the failure mode is basically harmless so let's just let it get fixed in KVM rather than pandering to it?
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