From: Andrew Jones <drjones@redhat.com> To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: maz@kernel.org, steven.price@arm.com, pbonzini@redhat.com Subject: [PATCH v2 2/6] KVM: arm64: pvtime: Fix potential loss of stolen time Date: Tue, 4 Aug 2020 19:06:00 +0200 [thread overview] Message-ID: <20200804170604.42662-3-drjones@redhat.com> (raw) In-Reply-To: <20200804170604.42662-1-drjones@redhat.com> We should only check current->sched_info.run_delay once when updating stolen time. Otherwise there's a chance there could be a change between checks that we miss (preemption disabling comes after vcpu request checks). Signed-off-by: Andrew Jones <drjones@redhat.com> --- arch/arm64/kvm/pvtime.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c index c3ef4ebd6846..95f9580275b1 100644 --- a/arch/arm64/kvm/pvtime.c +++ b/arch/arm64/kvm/pvtime.c @@ -13,6 +13,7 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; + u64 last_steal = vcpu->arch.steal.last_steal; u64 steal; __le64 steal_le; u64 offset; @@ -24,8 +25,8 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) /* Let's do the local bookkeeping */ steal = vcpu->arch.steal.steal; - steal += current->sched_info.run_delay - vcpu->arch.steal.last_steal; - vcpu->arch.steal.last_steal = current->sched_info.run_delay; + vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay); + steal += vcpu->arch.steal.last_steal - last_steal; vcpu->arch.steal.steal = steal; steal_le = cpu_to_le64(steal); -- 2.25.4
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Jones <drjones@redhat.com> To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: maz@kernel.org, pbonzini@redhat.com, steven.price@arm.com Subject: [PATCH v2 2/6] KVM: arm64: pvtime: Fix potential loss of stolen time Date: Tue, 4 Aug 2020 19:06:00 +0200 [thread overview] Message-ID: <20200804170604.42662-3-drjones@redhat.com> (raw) In-Reply-To: <20200804170604.42662-1-drjones@redhat.com> We should only check current->sched_info.run_delay once when updating stolen time. Otherwise there's a chance there could be a change between checks that we miss (preemption disabling comes after vcpu request checks). Signed-off-by: Andrew Jones <drjones@redhat.com> --- arch/arm64/kvm/pvtime.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/pvtime.c b/arch/arm64/kvm/pvtime.c index c3ef4ebd6846..95f9580275b1 100644 --- a/arch/arm64/kvm/pvtime.c +++ b/arch/arm64/kvm/pvtime.c @@ -13,6 +13,7 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) { struct kvm *kvm = vcpu->kvm; + u64 last_steal = vcpu->arch.steal.last_steal; u64 steal; __le64 steal_le; u64 offset; @@ -24,8 +25,8 @@ void kvm_update_stolen_time(struct kvm_vcpu *vcpu) /* Let's do the local bookkeeping */ steal = vcpu->arch.steal.steal; - steal += current->sched_info.run_delay - vcpu->arch.steal.last_steal; - vcpu->arch.steal.last_steal = current->sched_info.run_delay; + vcpu->arch.steal.last_steal = READ_ONCE(current->sched_info.run_delay); + steal += vcpu->arch.steal.last_steal - last_steal; vcpu->arch.steal.steal = steal; steal_le = cpu_to_le64(steal); -- 2.25.4 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
next prev parent reply other threads:[~2020-08-04 17:08 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-04 17:05 [PATCH v2 0/6] KVM: arm64: pvtime: Fixes and a new cap Andrew Jones 2020-08-04 17:05 ` Andrew Jones 2020-08-04 17:05 ` [PATCH v2 1/6] KVM: arm64: pvtime: steal-time is only supported when configured Andrew Jones 2020-08-04 17:05 ` Andrew Jones 2020-08-04 17:06 ` Andrew Jones [this message] 2020-08-04 17:06 ` [PATCH v2 2/6] KVM: arm64: pvtime: Fix potential loss of stolen time Andrew Jones 2020-08-04 17:06 ` [PATCH v2 3/6] KVM: arm64: Drop type input from kvm_put_guest Andrew Jones 2020-08-04 17:06 ` Andrew Jones 2020-08-04 17:06 ` [PATCH v2 4/6] KVM: arm64: pvtime: Fix stolen time accounting across migration Andrew Jones 2020-08-04 17:06 ` Andrew Jones 2020-08-04 17:06 ` [PATCH v2 5/6] KVM: Documentation: Minor fixups Andrew Jones 2020-08-04 17:06 ` Andrew Jones 2020-08-04 17:06 ` [PATCH v2 6/6] arm64/x86: KVM: Introduce steal-time cap Andrew Jones 2020-08-04 17:06 ` Andrew Jones 2020-08-05 15:37 ` [PATCH v2 0/6] KVM: arm64: pvtime: Fixes and a new cap Steven Price 2020-08-05 15:37 ` Steven Price 2020-08-19 12:50 ` Andrew Jones 2020-08-19 12:50 ` Andrew Jones 2020-08-21 13:04 ` Marc Zyngier 2020-08-21 13:04 ` Marc Zyngier
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