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From:   Marc Zyngier <maz@kernel.org>
To:     linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Jason Cooper <jason@lakedaemon.net>,
        Robert Richter <rrichter@marvell.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Zenghui Yu <yuzenghui@huawei.com>,
        Eric Auger <eric.auger@redhat.com>,
        James Morse <james.morse@arm.com>,
        Julien Thierry <julien.thierry.kdev@gmail.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH v4 14/20] KVM: arm64: GICv4.1: Let doorbells be auto-enabled
Date:   Fri, 14 Feb 2020 14:57:30 +0000
Message-Id: <20200214145736.18550-15-maz@kernel.org>
In-Reply-To: <20200214145736.18550-1-maz@kernel.org>
References: <20200214145736.18550-1-maz@kernel.org>
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As GICv4.1 understands the life cycle of doorbells (instead of
just randomly firing them at the most inconvenient time), just
enable them at irq_request time, and be done with it.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 virt/kvm/arm/vgic/vgic-v4.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
index 1eb0f8c76219..c2fcde104ea2 100644
--- a/virt/kvm/arm/vgic/vgic-v4.c
+++ b/virt/kvm/arm/vgic/vgic-v4.c
@@ -141,6 +141,7 @@ int vgic_v4_init(struct kvm *kvm)
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		int irq = dist->its_vm.vpes[i]->irq;
+		unsigned long irq_flags = DB_IRQ_FLAGS;
 
 		/*
 		 * Don't automatically enable the doorbell, as we're
@@ -148,8 +149,14 @@ int vgic_v4_init(struct kvm *kvm)
 		 * blocked. Also disable the lazy disabling, as the
 		 * doorbell could kick us out of the guest too
 		 * early...
+		 *
+		 * On GICv4.1, the doorbell is managed in HW and must
+		 * be left enabled.
 		 */
-		irq_set_status_flags(irq, DB_IRQ_FLAGS);
+		if (kvm_vgic_global_state.has_gicv4_1)
+			irq_flags &= ~IRQ_NOAUTOEN;
+		irq_set_status_flags(irq, irq_flags);
+
 		ret = request_irq(irq, vgic_v4_doorbell_handler,
 				  0, "vcpu", vcpu);
 		if (ret) {
-- 
2.20.1