commit 4f2f61fc507176edd65826fbedc8987dea29b9d5
author Wanpeng Li <wanpengli@tencent.com> Sun Feb 04 22:57:58 2018 -0800
committer Paolo Bonzini <pbonzini@redhat.com> Sat Feb 24 01:43:49 2018 +0100
tree 99fe7048c8fbcd27f6af8a19267490c1bc1a3b9b
parent afdc3f588850a6fbc996205ee2d472eb4426afb3

KVM: X86: Avoid traversing all the cpus for pv tlb flush when steal time is disabled

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 KrÄmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kernel/kvm.c

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index ee7d5c9..bc1a272 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -545,7 +545,8 @@ static void __init kvm_guest_init(void)
 		pv_time_ops.steal_clock = kvm_steal_clock;
 	}
 
-	if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH))
+	if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+	    !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))
@@ -633,7 +634,8 @@ static __init int kvm_setup_pv_tlb_flush(void)
 {
 	int cpu;
 
-	if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH)) {
+	if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+	    !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));