linux-kernel - [PATCH v5 15/26] KVM: arm/arm64: GICv4: Handle MOVALL applied to a vPE

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Date:   Fri, 27 Oct 2017 15:28:44 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Christoffer Dall <christoffer.dall@...aro.org>,
        Eric Auger <eric.auger@...hat.com>,
        Shanker Donthineni <shankerd@...eaurora.org>,
        Mark Rutland <mark.rutland@....com>,
        Shameerali Kolothum Thodi 
        <shameerali.kolothum.thodi@...wei.com>,
        Andre Przywara <Andre.Przywara@....com>
Subject: [PATCH v5 15/26] KVM: arm/arm64: GICv4: Handle MOVALL applied to a vPE

The current implementation of MOVALL doesn't allow us to call
into the core ITS code as we hold a number of spinlocks.

Let's try a method used in other parts of the code, were we copy
the intids of the candicate interrupts, and then do whatever
we need to do with them outside of the critical section.

This allows us to move the interrupts one by one, at the expense
of a bit of CPU time. Who cares? MOVALL is such a stupid command
anyway...

Reviewed-by: Christoffer Dall <christoffer.dall@...aro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
 virt/kvm/arm/vgic/vgic-its.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 5778b50911e8..0b7e648e7a0c 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1148,11 +1148,12 @@ static int vgic_its_cmd_handle_invall(struct kvm *kvm, struct vgic_its *its,
 static int vgic_its_cmd_handle_movall(struct kvm *kvm, struct vgic_its *its,
 				      u64 *its_cmd)
 {
-	struct vgic_dist *dist = &kvm->arch.vgic;
 	u32 target1_addr = its_cmd_get_target_addr(its_cmd);
 	u32 target2_addr = its_cmd_mask_field(its_cmd, 3, 16, 32);
 	struct kvm_vcpu *vcpu1, *vcpu2;
 	struct vgic_irq *irq;
+	u32 *intids;
+	int irq_count, i;
 
 	if (target1_addr >= atomic_read(&kvm->online_vcpus) ||
 	    target2_addr >= atomic_read(&kvm->online_vcpus))
@@ -1164,19 +1165,19 @@ static int vgic_its_cmd_handle_movall(struct kvm *kvm, struct vgic_its *its,
 	vcpu1 = kvm_get_vcpu(kvm, target1_addr);
 	vcpu2 = kvm_get_vcpu(kvm, target2_addr);
 
-	spin_lock(&dist->lpi_list_lock);
+	irq_count = vgic_copy_lpi_list(vcpu1, &intids);
+	if (irq_count < 0)
+		return irq_count;
 
-	list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
-		spin_lock(&irq->irq_lock);
+	for (i = 0; i < irq_count; i++) {
+		irq = vgic_get_irq(kvm, NULL, intids[i]);
 
-		if (irq->target_vcpu == vcpu1)
-			irq->target_vcpu = vcpu2;
+		update_affinity(irq, vcpu2);
 
-		spin_unlock(&irq->irq_lock);
+		vgic_put_irq(kvm, irq);
 	}
 
-	spin_unlock(&dist->lpi_list_lock);
-
+	kfree(intids);
 	return 0;
 }
 
-- 
2.11.0