From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Micro optimization to avoid calling wbinvd twice on the CPU that has to
emulate it. As we might be preempted between smp_call_function_many and
the local wbinvd, the cache might be filled again so that real work
could be done uselessly.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
I can fold the first patch into this one if it's preferred.
arch/x86/kvm/x86.c | 10 ++++++----
1 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0ed6dad..58e8232 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4012,13 +4012,15 @@ int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu)
return X86EMUL_CONTINUE;
if (kvm_x86_ops->has_wbinvd_exit()) {
- preempt_disable();
+ int cpu = get_cpu();
+
+ cpumask_set_cpu(cpu, vcpu->arch.wbinvd_dirty_mask);
smp_call_function_many(vcpu->arch.wbinvd_dirty_mask,
wbinvd_ipi, NULL, 1);
- preempt_enable();
+ put_cpu();
cpumask_clear(vcpu->arch.wbinvd_dirty_mask);
- }
- wbinvd();
+ } else
+ wbinvd();
return X86EMUL_CONTINUE;
}
EXPORT_SYMBOL_GPL(kvm_emulate_wbinvd);
--
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