From: Wanpeng Li <kernellwp@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Juri Lelli <juri.lelli@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Wanpeng Li <wanpengli@tencent.com>
Subject: [PATCH 06/10] KVM: Fix last_boosted_vcpu index assignment bug
Date: Mon, 10 Nov 2025 11:32:27 +0800 [thread overview]
Message-ID: <20251110033232.12538-7-kernellwp@gmail.com> (raw)
In-Reply-To: <20251110033232.12538-1-kernellwp@gmail.com>
From: Wanpeng Li <wanpengli@tencent.com>
From: Wanpeng Li <wanpengli@tencent.com>
In kvm_vcpu_on_spin(), the loop counter 'i' is incorrectly written to
last_boosted_vcpu instead of the actual vCPU index 'idx'. This causes
last_boosted_vcpu to store the loop iteration count rather than the
vCPU index, leading to incorrect round-robin behavior in subsequent
directed yield operations.
Fix this by using 'idx' instead of 'i' in the assignment.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
virt/kvm/kvm_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b7a0ae2a7b20..cde1eddbaa91 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4026,7 +4026,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
yielded = kvm_vcpu_yield_to(vcpu);
if (yielded > 0) {
- WRITE_ONCE(kvm->last_boosted_vcpu, i);
+ WRITE_ONCE(kvm->last_boosted_vcpu, idx);
break;
} else if (yielded < 0 && !--try) {
break;
--
2.43.0
next prev parent reply other threads:[~2025-11-10 3:33 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-10 3:32 [PATCH 00/10] sched/kvm: Semantics-aware vCPU scheduling for oversubscribed KVM Wanpeng Li
2025-11-10 3:32 ` [PATCH 01/10] sched: Add vCPU debooster infrastructure Wanpeng Li
2025-11-10 3:32 ` [PATCH 02/10] sched/fair: Add rate-limiting and validation helpers Wanpeng Li
2025-11-12 6:40 ` K Prateek Nayak
2025-11-12 6:44 ` K Prateek Nayak
2025-11-13 13:36 ` Wanpeng Li
2025-11-13 12:00 ` Wanpeng Li
2025-11-10 3:32 ` [PATCH 03/10] sched/fair: Add cgroup LCA finder for hierarchical yield Wanpeng Li
2025-11-12 6:50 ` K Prateek Nayak
2025-11-13 8:59 ` Wanpeng Li
2025-11-10 3:32 ` [PATCH 04/10] sched/fair: Add penalty calculation and application logic Wanpeng Li
2025-11-12 7:25 ` K Prateek Nayak
2025-11-13 13:25 ` Wanpeng Li
2025-11-10 3:32 ` [PATCH 05/10] sched/fair: Wire up yield deboost in yield_to_task_fair() Wanpeng Li
2025-11-10 5:16 ` kernel test robot
2025-11-10 5:16 ` kernel test robot
2025-11-10 3:32 ` Wanpeng Li [this message]
2025-11-21 0:35 ` [PATCH 06/10] KVM: Fix last_boosted_vcpu index assignment bug Sean Christopherson
2025-11-21 0:38 ` Sean Christopherson
2025-11-21 11:46 ` Wanpeng Li
2025-11-10 3:32 ` [PATCH 07/10] KVM: x86: Add IPI tracking infrastructure Wanpeng Li
2025-11-10 3:32 ` [PATCH 08/10] KVM: x86/lapic: Integrate IPI tracking with interrupt delivery Wanpeng Li
2025-11-10 3:32 ` [PATCH 09/10] KVM: Implement IPI-aware directed yield candidate selection Wanpeng Li
2025-11-10 3:39 ` [PATCH 10/10] KVM: Relaxed boost as safety net Wanpeng Li
2025-11-10 12:02 ` [PATCH 00/10] sched/kvm: Semantics-aware vCPU scheduling for oversubscribed KVM Christian Borntraeger
2025-11-12 5:01 ` Wanpeng Li
2025-11-18 8:11 ` Christian Borntraeger
2025-11-18 14:19 ` Wanpeng Li
2025-11-11 6:28 ` K Prateek Nayak
2025-11-12 4:54 ` Wanpeng Li
2025-11-12 6:07 ` K Prateek Nayak
2025-11-13 5:37 ` Wanpeng Li
2025-11-13 4:42 ` K Prateek Nayak
2025-11-13 8:33 ` Wanpeng Li
2025-11-13 9:48 ` K Prateek Nayak
2025-11-13 13:56 ` Wanpeng Li
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