[PATCH v4 18/20] KVM: arm64: GICv4.1: Reload VLPI configuration on distributor enable/disable

[Marc Zyngier]

Each time a Group-enable bit gets flipped, the state of these bits
needs to be forwarded to the hardware. This is a pretty heavy
handed operation, requiring all vcpus to reload their GICv4
configuration. It is thus implemented as a new request type.

Of course, we only support Group-1 for now...

Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
 arch/arm/include/asm/kvm_host.h   | 1 +
 arch/arm64/include/asm/kvm_host.h | 1 +
 virt/kvm/arm/arm.c                | 8 ++++++++
 virt/kvm/arm/vgic/vgic-mmio-v3.c  | 5 ++++-
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index c3314b286a61..7104babef15a 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -39,6 +39,7 @@
 #define KVM_REQ_IRQ_PENDING	KVM_ARCH_REQ(1)
 #define KVM_REQ_VCPU_RESET	KVM_ARCH_REQ(2)
 #define KVM_REQ_RECORD_STEAL	KVM_ARCH_REQ(3)
+#define KVM_REQ_RELOAD_GICv4	KVM_ARCH_REQ(4)
 
 DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
 
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index d87aa609d2b6..90b86f349ceb 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -44,6 +44,7 @@
 #define KVM_REQ_IRQ_PENDING	KVM_ARCH_REQ(1)
 #define KVM_REQ_VCPU_RESET	KVM_ARCH_REQ(2)
 #define KVM_REQ_RECORD_STEAL	KVM_ARCH_REQ(3)
+#define KVM_REQ_RELOAD_GICv4	KVM_ARCH_REQ(4)
 
 DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
 
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index d65a0faa46d8..d21e17b7af45 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -625,6 +625,14 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu)
 
 		if (kvm_check_request(KVM_REQ_RECORD_STEAL, vcpu))
 			kvm_update_stolen_time(vcpu);
+
+		if (kvm_check_request(KVM_REQ_RELOAD_GICv4, vcpu)) {
+			/* The distributor enable bits were changed */
+			preempt_disable();
+			vgic_v4_put(vcpu, false);
+			vgic_v4_load(vcpu);
+			preempt_enable();
+		}
 	}
 }
 
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index 442f3b8c2559..48fd9fc229a2 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -132,7 +132,10 @@ static void vgic_mmio_write_v3_misc(struct kvm_vcpu *vcpu,
 		if (is_hwsgi != dist->nassgireq)
 			vgic_v4_configure_vsgis(vcpu->kvm);
 
-		if (!was_enabled && dist->enabled)
+		if (kvm_vgic_global_state.has_gicv4_1 &&
+		    was_enabled != dist->enabled)
+			kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_RELOAD_GICv4);
+		else if (!was_enabled && dist->enabled)
 			vgic_kick_vcpus(vcpu->kvm);
 
 		mutex_unlock(&vcpu->kvm->lock);
-- 
2.20.1