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From: Zhenzhong Duan <zhenzhong.duan@oracle.com>
To: linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org, mtosatti@redhat.com,
	joao.m.martins@oracle.com, rafael.j.wysocki@intel.com,
	rkrcmar@redhat.com, pbonzini@redhat.com,
	Zhenzhong Duan <zhenzhong.duan@oracle.com>
Subject: [PATCH 2/5] KVM: add a check to ensure grow start value is nonzero
Date: Sat, 26 Oct 2019 11:23:56 +0800	[thread overview]
Message-ID: <1572060239-17401-3-git-send-email-zhenzhong.duan@oracle.com> (raw)
In-Reply-To: <1572060239-17401-1-git-send-email-zhenzhong.duan@oracle.com>

vcpu->halt_poll_ns could be zeroed in certain cases (e.g. by
halt_poll_ns_shrink). If halt_poll_ns_grow_start is zero,
vcpu->halt_poll_ns will never be larger than zero.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
---
 virt/kvm/kvm_main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2ca2979..1b6fe3b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2266,6 +2266,13 @@ static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
 		goto out;
 
 	val *= grow;
+
+	/*
+	 * vcpu->halt_poll_ns needs a nonzero start point to grow if it's zero.
+	 */
+	if (!grow_start)
+		grow_start = 1;
+
 	if (val < grow_start)
 		val = grow_start;
 
-- 
1.8.3.1


  parent reply	other threads:[~2019-10-26  3:25 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-26  3:23 [PATCH 0/5] misc fixes on halt-poll code both KVM and guest Zhenzhong Duan
2019-10-26  3:23 ` [PATCH 1/5] KVM: simplify branch check in host poll code Zhenzhong Duan
2019-11-01 21:03   ` Marcelo Tosatti
2019-11-04  3:49     ` Zhenzhong Duan
2019-10-26  3:23 ` Zhenzhong Duan [this message]
2019-11-11 13:49   ` [PATCH 2/5] KVM: add a check to ensure grow start value is nonzero Paolo Bonzini
2019-10-26  3:23 ` [PATCH 3/5] KVM: ensure pool time is longer than block_ns Zhenzhong Duan
2019-11-01 21:16   ` Marcelo Tosatti
2019-11-11 13:53     ` Paolo Bonzini
2019-11-12 12:14       ` Zhenzhong Duan
2019-10-26  3:23 ` [PATCH 4/5] cpuidle-haltpoll: add a check to ensure grow start value is nonzero Zhenzhong Duan
2019-11-01 21:19   ` Marcelo Tosatti
2019-11-04  2:56     ` Zhenzhong Duan
2019-11-11 13:54       ` Paolo Bonzini
2019-10-26  3:23 ` [PATCH 5/5] cpuidle-haltpoll: fix up the branch check Zhenzhong Duan
2019-11-01 21:26   ` Marcelo Tosatti
2019-11-04  3:10     ` Zhenzhong Duan
2019-11-04 15:01       ` Marcelo Tosatti
2019-11-05  6:49         ` Zhenzhong Duan

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