[RFC PATCH 09/13] KVM: arm64: Couple vSGI enablement with per-vCPU vPE allocation

[Maximilian Dittgen]

When KVM_ENABLE_VCPU_VLPI is enabled, vCPU vPEs are
dynamically allocated and dislocated ad-hoc. vSGI
direct injection requires receiving vCPUs to have
vPEs, meaning we must couple vSGI enablement with
vPE allocation to avoid injecting vSGIs to nonexistent
vPEs.

Modify vgic_v4_configure_sgis() to validate whether
a target vCPU has an assigned vPE before calling
vgic_v4_enable_vsgis() on boot. Call vgic_v4_enable_vsgis()
and vgic_v4_disable_vsgis() during vCPU vPE alloc and free
within vLPI enablement and disablement functions.

Signed-off-by: Maximilian Dittgen <mdittgen at amazon.de>
---
 arch/arm64/kvm/vgic/vgic-v4.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c
index b7dbc1789c90..5d6694d366b5 100644
--- a/arch/arm64/kvm/vgic/vgic-v4.c
+++ b/arch/arm64/kvm/vgic/vgic-v4.c
@@ -198,7 +198,7 @@ void vgic_v4_configure_vsgis(struct kvm *kvm)
 	kvm_arm_halt_guest(kvm);
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
-		if (dist->nassgireq)
+		if (dist->nassgireq && kvm_vgic_query_vcpu_vlpi(vcpu) > 0)
 			vgic_v4_enable_vsgis(vcpu);
 		else
 			vgic_v4_disable_vsgis(vcpu);
@@ -838,6 +838,13 @@ int kvm_vgic_enable_vcpu_vlpi(struct kvm_vcpu *vcpu)
 	if (ret)
 		return ret;
 
+	/* Enable direct vSGIs */
+	if (kvm_vgic_global_state.has_gicv4_1 && vcpu->kvm->arch.vgic.nassgireq) {
+		mutex_lock(&vcpu->kvm->arch.config_lock);
+		vgic_v4_enable_vsgis(vcpu);
+		mutex_unlock(&vcpu->kvm->arch.config_lock);
+	}
+
 	/*
 	 * Upgrade existing LPIs to vLPIs. We
 	 * do not need to error check since
@@ -859,6 +866,8 @@ int kvm_vgic_disable_vcpu_vlpi(struct kvm_vcpu *vcpu)
 
 	downgrade_existing_vlpis_to_lpis(vcpu);
 
+	vgic_v4_disable_vsgis(vcpu);
+
 	return vgic_v4_vcpu_teardown(vcpu);
 }
 
-- 
2.50.1 (Apple Git-155)




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