[4/5] KVM: arm64: Restructure the point where has_run_once is advertised

Commit Message

Marc Zyngier Oct. 15, 2021, 9:08 a.m. UTC

Restructure kvm_arch_vcpu_run_pid_change() to set the has_run_once
flag after having completed all the "run once" activities.

This includes moving the flip of the userspace irqchip static key
to a point where nothing can fail (the current code could end-up
in a bizarre state in a few error cases).

Signed-off-by: Marc Zyngier <[e-mail]>
---
 arch/arm64/kvm/arm.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

Patch

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 30692497c4ea..5bcdf8073854 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -603,8 +603,6 @@  int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 	if (likely(vcpu->arch.has_run_once))
 		return 0;
 
-	vcpu->arch.has_run_once = true;
-
 	kvm_arm_vcpu_init_debug(vcpu);
 
 	if (likely(irqchip_in_kernel(kvm))) {
@@ -615,12 +613,6 @@  int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 		ret = kvm_vgic_map_resources(kvm);
 		if (ret)
 			return ret;
-	} else {
-		/*
-		 * Tell the rest of the code that there are userspace irqchip
-		 * VMs in the wild.
-		 */
-		static_branch_inc(&userspace_irqchip_in_use);
 	}
 
 	ret = kvm_timer_enable(vcpu);
@@ -628,6 +620,18 @@  int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 		return ret;
 
 	ret = kvm_arm_pmu_v3_enable(vcpu);
+	if (ret)
+		return ret;
+
+	if (!irqchip_in_kernel(kvm)) {
+		/*
+		 * Tell the rest of the code that there are userspace irqchip
+		 * VMs in the wild.
+		 */
+		static_branch_inc(&userspace_irqchip_in_use);
+	}
+
+	vcpu->arch.has_run_once = true;
 
 	return ret;
 }