We do track the current steal time of the host CPUs. Let us use
this value to disable halt polling if the steal time goes beyond
a predefined value. (12.5% for now).
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
arch/s390/include/asm/kvm_host.h | 6 ++++++
arch/s390/kvm/Kconfig | 1 +
2 files changed, 7 insertions(+)
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index a4962761e1dd..f699983a8d09 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -884,6 +884,12 @@ struct kvm_arch_async_pf {
unsigned long pfault_token;
};
+static inline bool kvm_arch_no_poll(void)
+{
+ /* do not poll with more than 12.5% steal */
+ return S390_lowcore.avg_steal_timer > (TICK_USEC << 12) / 8;
+}
+
bool kvm_arch_can_inject_async_page_present(struct kvm_vcpu *vcpu);
void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu,
diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index 767453faacfc..e987e73738b5 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -31,6 +31,7 @@ config KVM
select HAVE_KVM_IRQFD
select HAVE_KVM_IRQ_ROUTING
select HAVE_KVM_INVALID_WAKEUPS
+ select HAVE_KVM_NO_POLL
select SRCU
select KVM_VFIO
---help---
--
2.17.1
