linux-kernel - [RFC 2/4] KVM: arm: vgic: add forwarded irq rbtree lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1416766373-13569-3-git-send-email-eric.auger@linaro.org>
Date:	Sun, 23 Nov 2014 19:12:51 +0100
From:	Eric Auger <eric.auger@...aro.org>
To:	eric.auger@...com, eric.auger@...aro.org,
	christoffer.dall@...aro.org, marc.zyngier@....com,
	linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
	kvm@...r.kernel.org, alex.williamson@...hat.com,
	joel.schopp@....com, kim.phillips@...escale.com, paulus@...ba.org,
	gleb@...nel.org, pbonzini@...hat.com
Cc:	linux-kernel@...r.kernel.org, patches@...aro.org,
	will.deacon@....com, a.motakis@...tualopensystems.com,
	a.rigo@...tualopensystems.com, john.liuli@...wei.com,
	ming.lei@...onical.com, feng.wu@...el.com
Subject: [RFC 2/4] KVM: arm: vgic: add forwarded irq rbtree lock

Add a lock related to the rb tree manipulation. The rb tree can be
searched in one thread (irqfd handler for instance) and map/unmap
may happen in another.

Signed-off-by: Eric Auger <eric.auger@...aro.org>

---

v2 -> v3:
re-arrange lock sequence in vgic_map_phys_irq
---
 include/kvm/arm_vgic.h |  1 +
 virt/kvm/arm/vgic.c    | 56 ++++++++++++++++++++++++++++++++++++--------------
 2 files changed, 42 insertions(+), 15 deletions(-)

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index ea31ac6..9b3290b 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -220,6 +220,7 @@ struct vgic_dist {
 	unsigned long		*irq_pending_on_cpu;
 
 	struct rb_root		irq_phys_map;
+	spinlock_t			rb_tree_lock;
 #endif
 };
 
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 5484e3d..f592219 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1750,9 +1750,22 @@ static struct rb_root *vgic_get_irq_phys_map(struct kvm_vcpu *vcpu,
 
 int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq)
 {
-	struct rb_root *root = vgic_get_irq_phys_map(vcpu, virt_irq);
-	struct rb_node **new = &root->rb_node, *parent = NULL;
+	struct rb_root *root;
+	struct rb_node **new, *parent = NULL;
 	struct irq_phys_map *new_map;
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	root = vgic_get_irq_phys_map(vcpu, virt_irq);
+	new = &root->rb_node;
+
+	new_map = kzalloc(sizeof(*new_map), GFP_KERNEL);
+	if (!new_map)
+		return -ENOMEM;
+
+	new_map->virt_irq = virt_irq;
+	new_map->phys_irq = phys_irq;
+
+	spin_lock(&dist->rb_tree_lock);
 
 	/* Boilerplate rb_tree code */
 	while (*new) {
@@ -1764,19 +1777,16 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq)
 			new = &(*new)->rb_left;
 		else if (this->virt_irq > virt_irq)
 			new = &(*new)->rb_right;
-		else
+		else {
+			kfree(new_map);
+			spin_unlock(&dist->rb_tree_lock);
 			return -EEXIST;
+		}
 	}
 
-	new_map = kzalloc(sizeof(*new_map), GFP_KERNEL);
-	if (!new_map)
-		return -ENOMEM;
-
-	new_map->virt_irq = virt_irq;
-	new_map->phys_irq = phys_irq;
-
 	rb_link_node(&new_map->node, parent, new);
 	rb_insert_color(&new_map->node, root);
+	spin_unlock(&dist->rb_tree_lock);
 
 	return 0;
 }
@@ -1805,24 +1815,39 @@ static struct irq_phys_map *vgic_irq_map_search(struct kvm_vcpu *vcpu,
 
 int vgic_get_phys_irq(struct kvm_vcpu *vcpu, int virt_irq)
 {
-	struct irq_phys_map *map = vgic_irq_map_search(vcpu, virt_irq);
+	struct irq_phys_map *map;
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+	int ret;
+
+	spin_lock(&dist->rb_tree_lock);
+	map = vgic_irq_map_search(vcpu, virt_irq);
 
 	if (map)
-		return map->phys_irq;
+		ret = map->phys_irq;
+	else
+		ret =  -ENOENT;
+
+	spin_unlock(&dist->rb_tree_lock);
+	return ret;
 
-	return -ENOENT;
 }
 
 int vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq)
 {
-	struct irq_phys_map *map = vgic_irq_map_search(vcpu, virt_irq);
+	struct irq_phys_map *map;
+	struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+
+	spin_lock(&dist->rb_tree_lock);
+
+	map = vgic_irq_map_search(vcpu, virt_irq);
 
 	if (map && map->phys_irq == phys_irq) {
 		rb_erase(&map->node, vgic_get_irq_phys_map(vcpu, virt_irq));
 		kfree(map);
+		spin_unlock(&dist->rb_tree_lock);
 		return 0;
 	}
-
+	spin_unlock(&dist->rb_tree_lock);
 	return -ENOENT;
 }
 
@@ -2078,6 +2103,7 @@ int kvm_vgic_create(struct kvm *kvm)
 	}
 
 	spin_lock_init(&kvm->arch.vgic.lock);
+	spin_lock_init(&kvm->arch.vgic.rb_tree_lock);
 	kvm->arch.vgic.in_kernel = true;
 	kvm->arch.vgic.vctrl_base = vgic->vctrl_base;
 	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/