From: Wanpeng Li <wanpengli@tencent.com> mainline inclusion from mainline-5.4 commit 1328edca4a142ee3c7442d1eece2c3ca383eff35 category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=34 CVE: NA The downside of guest side polling is that polling is performed even with other runnable tasks in the host. However, even if poll in kvm can aware whether or not other runnable tasks in the same pCPU, it can still incur extra overhead in over-subscribe scenario. Now we can just enable guest polling when dedicated pCPUs are available. Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Yubo Miao <miaoyubo@huawei.com> Signed-off-by: Xiangyou Xie <xiexiangyou@huawei.com> Reviewed-by: Hailiang Zhang <zhang.zhanghailiang@huawei.com> Reviewed-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: Jiajun Chen <chenjiajun8@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- arch/x86/kernel/kvm.c | 1 + drivers/cpuidle/cpuidle-haltpoll.c | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index cafd1a3faa04f..9c52eec69bfc6 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -703,6 +703,7 @@ unsigned int kvm_arch_para_hints(void) { return cpuid_edx(kvm_cpuid_base() | KVM_CPUID_FEATURES); } +EXPORT_SYMBOL_GPL(kvm_arch_para_hints); static uint32_t __init kvm_detect(void) { diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c index 49a65c6fe91e3..932390b028f1d 100644 --- a/drivers/cpuidle/cpuidle-haltpoll.c +++ b/drivers/cpuidle/cpuidle-haltpoll.c @@ -97,7 +97,8 @@ static int __init haltpoll_init(void) cpuidle_poll_state_init(drv); - if (!kvm_para_available()) + if (!kvm_para_available() || + !kvm_para_has_hint(KVM_HINTS_REALTIME)) return -ENODEV; ret = cpuidle_register_driver(drv); -- 2.25.1