directly call wbinvd for local cpu, instead of calling atomic
cpumask_set_cpu to set local cpu, and then check if local cpu
needs to run in on_each_cpu_mask
on_each_cpu_mask is less efficient than smp_call_function_many,
since it will close preempt again and running call function by
checking flag with SCF_RUN_LOCAL. and here wbinvd can be called
directly
In fact, This change reverts commit 2eec73437487 ("KVM: x86: Avoid
issuing wbinvd twice"), since smp_call_function_many is skiping the
local cpu (as description of c2162e13d6e2f), wbinvd is not issued
twice
and reverts commit c2162e13d6e2f ("KVM: X86: Fix missing local pCPU
when executing wbinvd on all dirty pCPUs") too, which fixed the
previous patch, when revert previous patch, it is not needed.
Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
---
diff v2: rewrite commit log
arch/x86/kvm/x86.c | 13 ++++++-------
1 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index aabd3a2..28c4c72 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6991,15 +6991,14 @@ static int kvm_emulate_wbinvd_noskip(struct kvm_vcpu *vcpu)
return X86EMUL_CONTINUE;
if (static_call(kvm_x86_has_wbinvd_exit)()) {
- int cpu = get_cpu();
-
- cpumask_set_cpu(cpu, vcpu->arch.wbinvd_dirty_mask);
- on_each_cpu_mask(vcpu->arch.wbinvd_dirty_mask,
+ preempt_disable();
+ smp_call_function_many(vcpu->arch.wbinvd_dirty_mask,
wbinvd_ipi, NULL, 1);
- put_cpu();
+ preempt_enable();
cpumask_clear(vcpu->arch.wbinvd_dirty_mask);
- } else
- wbinvd();
+ }
+
+ wbinvd();
return X86EMUL_CONTINUE;
}
--
1.7.1
