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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
	kvmarm@lists.cs.columbia.edu
Cc: 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] KVM: arm64: vgic-v4: Initialize GICv4.1 even in the absence of a virtual ITS
Date: Sat, 25 Apr 2020 10:44:26 +0100	[thread overview]
Message-ID: <20200425094426.162962-1-maz@kernel.org> (raw)

KVM now expects to be able to use HW-accelerated delivery of vSGIs
as soon as the guest has enabled thm. Unfortunately, we only
initialize the GICv4 context if we have a virtual ITS exposed to
the guest.

Fix it by always initializing the GICv4.1 context if it is
available on the host.

Fixes: 2291ff2f2a56 ("KVM: arm64: GICv4.1: Plumb SGI implementation selection in the distributor")
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 virt/kvm/arm/vgic/vgic-init.c    | 9 ++++++++-
 virt/kvm/arm/vgic/vgic-mmio-v3.c | 3 ++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index a963b9d766b73..8e6f350c3bcd1 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -294,8 +294,15 @@ int vgic_init(struct kvm *kvm)
 		}
 	}
 
-	if (vgic_has_its(kvm)) {
+	if (vgic_has_its(kvm))
 		vgic_lpi_translation_cache_init(kvm);
+
+	/*
+	 * If we have GICv4.1 enabled, unconditionnaly request enable the
+	 * v4 support so that we get HW-accelerated vSGIs. Otherwise, only
+	 * enable it if we present a virtual ITS to the guest.
+	 */
+	if (vgic_supports_direct_msis(kvm)) {
 		ret = vgic_v4_init(kvm);
 		if (ret)
 			goto out;
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index e72dcc4542475..26b11dcd45524 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -50,7 +50,8 @@ bool vgic_has_its(struct kvm *kvm)
 
 bool vgic_supports_direct_msis(struct kvm *kvm)
 {
-	return kvm_vgic_global_state.has_gicv4 && vgic_has_its(kvm);
+	return (kvm_vgic_global_state.has_gicv4_1 ||
+		(kvm_vgic_global_state.has_gicv4 && vgic_has_its(kvm)));
 }
 
 /*
-- 
2.26.2


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             reply	other threads:[~2020-04-25  9:45 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-25  9:44 Marc Zyngier [this message]
2020-04-30 11:24 ` [PATCH] KVM: arm64: vgic-v4: Initialize GICv4.1 even in the absence of a virtual ITS Zenghui Yu
2020-04-30 11:39   ` Marc Zyngier

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