Re: [PATCH 0/5 V5] Avoid soft lockup message when KVM is stopped byhost

From: Amit Shah
Date: Mon Dec 19 2011 - 07:52:37 EST


On (Thu) 15 Dec 2011 [13:55:15], Avi Kivity wrote:
> On 12/08/2011 01:34 PM, Amit Shah wrote:
> > On (Mon) 05 Dec 2011 [15:18:59], Eric B Munson wrote:
> > > When a guest kernel is stopped by the host hypervisor it can look like a soft
> > > lockup to the guest kernel. This false warning can mask later soft lockup
> > > warnings which may be real. This patch series adds a method for a host
> > > hypervisor to communicate to a guest kernel that it is being stopped. The
> > > final patch in the series has the watchdog check this flag when it goes to
> > > issue a soft lockup warning and skip the warning if the guest knows it was
> > > stopped.
> >
> > Guest S4 would need similar treatment, and I think the code in the two
> > approaches can be shared. Just something to consider.
> >
>
> Why does S4 need any treatment? The guest is aware that it's sleeping,
> unlike the other cases treated here.

Er, right.

S4 needs some treatment, though, as resume after s4 doesn't work with
kvmclock enabled. I didn't realise this series was only handling the
soft lockup case.

Amit
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