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Subject[PATCH 2/6] Add functions to check if the host has stopped the vm
Date
When a host stops or suspends a VM it will set a flag to show this.  The
watchdog will use these functions to determine if a softlockup is real, or the
result of a suspended VM.

Signed-off-by: Eric B Munson <emunson@mgebm.net>
---
arch/x86/include/asm/pvclock.h | 2 ++
arch/x86/kernel/kvmclock.c | 19 +++++++++++++++++++
2 files changed, 21 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index c59cc97..7d3ba41 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -13,6 +13,8 @@ void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
struct timespec *ts);
void pvclock_resume(void);

+bool kvm_check_and_clear_host_stopped(int cpu);
+
/*
* Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
* yielding a 64-bit result.
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index c1a0188..8ddcfaf 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -113,6 +113,25 @@ static void kvm_get_preset_lpj(void)
preset_lpj = lpj;
}

+bool kvm_check_and_clear_host_stopped(int cpu)
+{
+ bool ret = false;
+ struct pvclock_vcpu_time_info *src;
+
+ /*
+ * per_cpu() is safe here because this function is only called from
+ * timer functions where preemption is already disabled.
+ */
+ WARN_ON(!in_atomic());
+ src = &per_cpu(hv_clock, cpu);
+ if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) {
+ src->flags = src->flags & (~PVCLOCK_GUEST_STOPPED);
+ ret = true;
+ }
+
+ return ret;
+}
+
static struct clocksource kvm_clock = {
.name = "kvm-clock",
.read = kvm_clock_get_cycles,
--
1.7.5.4


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