[PATCH v5 21/23] KVM: arm64: GICv4.1: Reload VLPI configuration on distributor enable/disable

Marc Zyngier
2020-03-04T20:36:58Z

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@kernel.org>
---
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 a827b4d60d38..3da57e863df6 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 57fd46acd058..32c8a675e5a4 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 eda7b624eab8..4d864f857ac8 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