[v8,04/81] KVM: add kvm_vcpu_kick_and_wait()

Commit Message

Adalbert Lazăr March 30, 2020, 10:11 a.m. UTC

This function is needed for the KVMI_VCPU_PAUSE command. There are
cases when it is easier for the introspection tool if it knows that
the vCPU doesn't run guest code when the command completed, without
the need to wait for the KVMI_EVENT_PAUSE_VCPU event.

Signed-off-by: Adalbert Lazăr <[e-mail]>
---
 include/linux/kvm_host.h |  1 +
 virt/kvm/kvm_main.c      | 10 ++++++++++
 2 files changed, 11 insertions(+)

Patch

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index bcb9b2ac0791..6890f0a85dba 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -799,6 +799,7 @@  void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu);
 void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu);
 bool kvm_vcpu_wake_up(struct kvm_vcpu *vcpu);
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
+void kvm_vcpu_kick_and_wait(struct kvm_vcpu *vcpu);
 int kvm_vcpu_yield_to(struct kvm_vcpu *target);
 void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu, bool usermode_vcpu_not_eligible);
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 70f03ce0e5c1..4c69ce5aa79c 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2567,6 +2567,16 @@  void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 EXPORT_SYMBOL_GPL(kvm_vcpu_kick);
 #endif /* !CONFIG_S390 */
 
+void kvm_vcpu_kick_and_wait(struct kvm_vcpu *vcpu)
+{
+	if (kvm_vcpu_wake_up(vcpu))
+		return;
+
+	if (kvm_request_needs_ipi(vcpu, KVM_REQUEST_WAIT))
+		smp_call_function_single(vcpu->cpu, ack_flush, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_kick_and_wait);
+
 int kvm_vcpu_yield_to(struct kvm_vcpu *target)
 {
 	struct pid *pid;