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From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>
Subject: [PATCH v2 2/2] KVM: X86: Avoid traversing all the cpus for pv tlb flush when steal time is disabled
Date: Sun,  4 Feb 2018 22:57:58 -0800	[thread overview]
Message-ID: <1517813878-22248-2-git-send-email-wanpengli@tencent.com> (raw)
In-Reply-To: <1517813878-22248-1-git-send-email-wanpengli@tencent.com>

From: Wanpeng Li <wanpengli@tencent.com>

Avoid traversing all the cpus for pv tlb flush when steal time 
is disabled since pv tlb flush depends on the field in steal time 
for shared data.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
 arch/x86/kernel/kvm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index f2a09cf..4f3c997 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -546,7 +546,8 @@ static void __init kvm_guest_init(void)
 	}
 
 	if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
-			!kvm_para_has_feature(KVM_FEATURE_PV_DEDICATED))
+			!kvm_para_has_feature(KVM_FEATURE_PV_DEDICATED) &&
+			kvm_para_has_feature(KVM_FEATURE_STEAL_TIME))
 		pv_mmu_ops.flush_tlb_others = kvm_flush_tlb_others;
 
 	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
@@ -635,7 +636,8 @@ static __init int kvm_setup_pv_tlb_flush(void)
 	int cpu;
 
 	if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
-			!kvm_para_has_feature(KVM_FEATURE_PV_DEDICATED)) {
+			!kvm_para_has_feature(KVM_FEATURE_PV_DEDICATED) &&
+			kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
 		for_each_possible_cpu(cpu) {
 			zalloc_cpumask_var_node(per_cpu_ptr(&__pv_tlb_mask, cpu),
 				GFP_KERNEL, cpu_to_node(cpu));
-- 
2.7.4

  reply	other threads:[~2018-02-05  6:59 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-05  6:57 [PATCH v2 1/2] KVM: X86: Add per-VM no-HLT-exiting capability Wanpeng Li
2018-02-05  6:57 ` Wanpeng Li [this message]
2018-02-13  5:02 ` Wanpeng Li
2018-02-13 16:02 ` Paolo Bonzini
2018-02-14  3:26   ` Wanpeng Li

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