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    SubjectRe: [PATCH 0/4 V13] Avoid soft lockup message when KVM is stopped by host
    On Mon, 5 Mar 2012 13:39:43 -0300, Marcelo Tosatti wrote:
    > On Tue, Feb 14, 2012 at 04:17:20PM -0500, Eric B Munson wrote:
    >> On Tue, 14 Feb 2012, Marcelo Tosatti wrote:
    >>
    >> > On Tue, Feb 14, 2012 at 10:50:13AM -0500, Eric B Munson wrote:
    >> > > On Tue, 14 Feb 2012, Marcelo Tosatti wrote:
    >> > >
    >> > > > On Tue, Feb 14, 2012 at 10:29:31AM -0500, Eric B Munson wrote:
    >> > > > > On Wed, 08 Feb 2012, 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.
    >> > > > > >
    >> > > > > > It was attempted to solve this in Qemu, but the side
    >> effects of saving and
    >> > > > > > restoring the clock and tsc for each vcpu put the wall
    >> clock of the guest behind
    >> > > > > > by the amount of time of the pause. This forces a guest
    >> to have ntp running
    >> > > > > > in order to keep the wall clock accurate.
    >> > > > >
    >> > > > > Avi,
    >> > > > >
    >> > > > > Is this set fit for merging or is there something else you
    >> want changed?
    >> > > >
    >> > > > Eric,
    >> > > >
    >> > > > On Message-ID: <20120210160536.GA23363@amt.cnet>, i asked:
    >> > > >
    >> > > > How is the stub getting included for other architectures
    >> again?
    >> > > >
    >> > >
    >> > > Marcelo,
    >> > >
    >> > > Sorry, I put out V13 to answer that. There is a stub in
    >> asm-generic that was
    >> > > lost in the V11-V12 rebase. This stub has be included in the
    >> V13 set.
    >> > >
    >> > > Eric
    >> >
    >> > Eric,
    >> >
    >> > I know the stub has been included in the series. But i am asking
    >> how
    >> > it is #include'ed for other architectures? (can't see that).
    >>
    >> Marcelo,
    >>
    >> kernel/watchdog.c now includes linux/kvm_para.h which includes
    >> asm/kvm_para.h.
    >> The check_and_clear function is defined in arch
    >> include/asm/kvm_para.h or in
    >> asm-generic/kvm_para.h for any arch lacking the specific header in
    >> their asm
    >> include dir. If I have misunderstood how these headers work, please
    >> let me
    >> know and I will fix it.
    >
    > There is no automatic inclusion of asm-generic/ headers. You must
    > create
    > kvm_para.h in each architecture's include/asm/ directory, #including
    > asm-generic/kvm_para.h.


    Okay, that will go into V16 then...

    Eric


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