Re: [RFC v2 2/9] KVM: ARM: VGIC: add forwarded irq rbtree lock
On 09/11/2014 05:09 AM, Christoffer Dall wrote:
On Mon, Sep 01, 2014 at 02:52:41PM +0200, Eric Auger wrote:
add a lock related to the rb tree manipulation. The rb tree can be
Ok, I can't hold myself back any longer.
Please begin sentences with a
capital letter. You don't do this in French? :)
Hi Christoffer,
yep that's understood ;-) Definitively we do. Just that I am discovering
it is common too in commits and comments ;-)
searched in one thread (irqfd handler for instance) and map/unmap
happen in another.
Signed-off-by: Eric Auger eric.au...@linaro.org
---
include/kvm/arm_vgic.h | 1 +
virt/kvm/arm/vgic.c| 46 +-
2 files changed, 38 insertions(+), 9 deletions(-)
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 743020f..3da244f 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -177,6 +177,7 @@ 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 8ef495b..dbc2a5a 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1630,9 +1630,15 @@ 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;
+
+spin_lock(dist-rb_tree_lock);
+
+root = vgic_get_irq_phys_map(vcpu, virt_irq);
+new = root-rb_node;
/* Boilerplate rb_tree code */
while (*new) {
@@ -1644,13 +1650,17 @@ 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 {
+spin_unlock(dist-rb_tree_lock);
return -EEXIST;
+}
can you initialize a ret variable to -EEXIST in the beginning of this
function, and add an out label above the unlock below, replace this
multi-line statement with a goto out, and set ret = 0 after the while
loop?
sure
}
new_map = kzalloc(sizeof(*new_map), GFP_KERNEL);
-if (!new_map)
+if (!new_map) {
+spin_unlock(dist-rb_tree_lock);
return -ENOMEM;
then this becomes ret = -ENOMEM; goto out;
OK
+}
new_map-virt_irq = virt_irq;
new_map-phys_irq = phys_irq;
@@ -1658,6 +1668,8 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int
virt_irq, int phys_irq)
rb_link_node(new_map-node, parent, new);
rb_insert_color(new_map-node, root);
+spin_unlock(dist-rb_tree_lock);
+
aren't you allocating memory with GFP_KERNEL while holding a spinlock
here?
oups. Thanks for noticing. I Will move the lock.
return 0;
}
@@ -1685,24 +1697,39 @@ 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;
initialize ret to -ENOENT and avoid the else statement.
ok
+
+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);
can kfree sleep? I don't remember. In any case, you can unlock before
calling kfree.
no it can't but I will move anyway.
return 0;
}
-
+spin_unlock(dist-rb_tree_lock);
return -ENOENT;
an out label and single unlock location would be preferred here as well
I think.
ok
Thansk
Eric
}
@@ -1898,6 +1925,7 @@ 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 =
Re: [RFC v2 2/9] KVM: ARM: VGIC: add forwarded irq rbtree lock
On Mon, Sep 01, 2014 at 02:52:41PM +0200, Eric Auger wrote:
add a lock related to the rb tree manipulation. The rb tree can be
Ok, I can't hold myself back any longer. Please begin sentences with a
capital letter. You don't do this in French? :)
searched in one thread (irqfd handler for instance) and map/unmap
happen in another.
Signed-off-by: Eric Auger eric.au...@linaro.org
---
include/kvm/arm_vgic.h | 1 +
virt/kvm/arm/vgic.c| 46 +-
2 files changed, 38 insertions(+), 9 deletions(-)
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 743020f..3da244f 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -177,6 +177,7 @@ 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 8ef495b..dbc2a5a 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1630,9 +1630,15 @@ 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;
+
+ spin_lock(dist-rb_tree_lock);
+
+ root = vgic_get_irq_phys_map(vcpu, virt_irq);
+ new = root-rb_node;
/* Boilerplate rb_tree code */
while (*new) {
@@ -1644,13 +1650,17 @@ 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 {
+ spin_unlock(dist-rb_tree_lock);
return -EEXIST;
+ }
can you initialize a ret variable to -EEXIST in the beginning of this
function, and add an out label above the unlock below, replace this
multi-line statement with a goto out, and set ret = 0 after the while
loop?
}
new_map = kzalloc(sizeof(*new_map), GFP_KERNEL);
- if (!new_map)
+ if (!new_map) {
+ spin_unlock(dist-rb_tree_lock);
return -ENOMEM;
then this becomes ret = -ENOMEM; goto out;
+ }
new_map-virt_irq = virt_irq;
new_map-phys_irq = phys_irq;
@@ -1658,6 +1668,8 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int
virt_irq, int phys_irq)
rb_link_node(new_map-node, parent, new);
rb_insert_color(new_map-node, root);
+ spin_unlock(dist-rb_tree_lock);
+
aren't you allocating memory with GFP_KERNEL while holding a spinlock
here?
return 0;
}
@@ -1685,24 +1697,39 @@ 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;
initialize ret to -ENOENT and avoid the else statement.
+
+ 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);
can kfree sleep? I don't remember. In any case, you can unlock before
calling kfree.
return 0;
}
-
+ spin_unlock(dist-rb_tree_lock);
return -ENOENT;
an out label and single unlock location would be preferred here as well
I think.
}
@@ -1898,6 +1925,7 @@ 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
--
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[RFC v2 2/9] 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
happen in another.
Signed-off-by: Eric Auger eric.au...@linaro.org
---
include/kvm/arm_vgic.h | 1 +
virt/kvm/arm/vgic.c| 46 +-
2 files changed, 38 insertions(+), 9 deletions(-)
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index 743020f..3da244f 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -177,6 +177,7 @@ 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 8ef495b..dbc2a5a 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1630,9 +1630,15 @@ 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;
+
+ spin_lock(dist-rb_tree_lock);
+
+ root = vgic_get_irq_phys_map(vcpu, virt_irq);
+ new = root-rb_node;
/* Boilerplate rb_tree code */
while (*new) {
@@ -1644,13 +1650,17 @@ 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 {
+ spin_unlock(dist-rb_tree_lock);
return -EEXIST;
+ }
}
new_map = kzalloc(sizeof(*new_map), GFP_KERNEL);
- if (!new_map)
+ if (!new_map) {
+ spin_unlock(dist-rb_tree_lock);
return -ENOMEM;
+ }
new_map-virt_irq = virt_irq;
new_map-phys_irq = phys_irq;
@@ -1658,6 +1668,8 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int
virt_irq, int 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;
}
@@ -1685,24 +1697,39 @@ 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;
}
@@ -1898,6 +1925,7 @@ 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
--
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