[RFC PATCH 05/22] KVM: x86: Introduce kvm_vcpu_make_runnable()

[Mingwei Zhang <mizhang@google.com>]

From: Jim Mattson <jmattson@google.com>

Factor out common code that handles the transition from
HALTED/AP_RESET_HOLD to RUNNABLE state. In addition to changing
mp_state, this transition has side effects (clearing pv_unhalted,
apf.halted) which must be handled consistently across all code paths.

As future patches add more side effects to this state transition, this
helper ensures they will be applied uniformly at all transition
points.

No functional change intended.

Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
---
 arch/x86/include/asm/kvm_host.h |  2 ++
 arch/x86/kvm/x86.c              | 16 +++++++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 6d9f763a7bb9d..04ef56d10cbb1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2283,6 +2283,8 @@ static inline bool kvm_is_supported_user_return_msr(u32 msr)
 	return kvm_find_user_return_msr(msr) >= 0;
 }
 
+void kvm_vcpu_make_runnable(struct kvm_vcpu *vcpu);
+
 u64 kvm_scale_tsc(u64 tsc, u64 ratio);
 u64 kvm_read_l1_tsc(struct kvm_vcpu *vcpu, u64 host_tsc);
 u64 kvm_calc_nested_tsc_offset(u64 l1_offset, u64 l2_offset, u64 l2_multiplier);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 83fe0a78146fc..3c6b0ca91e5f5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11167,6 +11167,16 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
 	return kvm_vcpu_running(vcpu) || kvm_vcpu_has_events(vcpu);
 }
 
+void kvm_vcpu_make_runnable(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED ||
+	    vcpu->arch.mp_state == KVM_MP_STATE_AP_RESET_HOLD)
+		vcpu->arch.pv.pv_unhalted = false;
+	vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+	vcpu->arch.apf.halted = false;
+}
+EXPORT_SYMBOL_GPL(kvm_vcpu_make_runnable);
+
 /* Called within kvm->srcu read side.  */
 static inline int vcpu_block(struct kvm_vcpu *vcpu)
 {
@@ -11222,12 +11232,8 @@ static inline int vcpu_block(struct kvm_vcpu *vcpu)
 	switch(vcpu->arch.mp_state) {
 	case KVM_MP_STATE_HALTED:
 	case KVM_MP_STATE_AP_RESET_HOLD:
-		vcpu->arch.pv.pv_unhalted = false;
-		vcpu->arch.mp_state =
-			KVM_MP_STATE_RUNNABLE;
-		fallthrough;
 	case KVM_MP_STATE_RUNNABLE:
-		vcpu->arch.apf.halted = false;
+		kvm_vcpu_make_runnable(vcpu);
 		break;
 	case KVM_MP_STATE_INIT_RECEIVED:
 		break;
-- 
2.47.0.371.ga323438b13-goog