Re: [PATCH 3/7] vfio: New external user group/file match

2017-06-14 Thread Auger Eric 
Hi,
On 09/06/2017 23:59, Alex Williamson wrote:
> At the point where the kvm-vfio pseudo device wants to release its
> vfio group reference, we can't always acquire a new reference to make
> that happen.  The group can be in a state where we wouldn't allow a
> new reference to be added.  This new helper function allows a caller
> to match a file to a group to facilitate this.  Given a file and
> group, report if they match.  Thus the caller needs to already have a
> group reference to match to the file.  This allows the deletion of a
> group without acquiring a new reference.
> 
> Signed-off-by: Alex Williamson 
> Cc: Paolo Bonzini 
Reviewed-by: Eric Auger 

Thanks

Eric
> ---
>  drivers/vfio/vfio.c  |9 +
>  include/linux/vfio.h |2 ++
>  virt/kvm/vfio.c  |   27 +++
>  3 files changed, 30 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index f2e24d5699f2..e6117de60f87 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -1776,6 +1776,15 @@ void vfio_group_put_external_user(struct vfio_group 
> *group)
>  }
>  EXPORT_SYMBOL_GPL(vfio_group_put_external_user);
>  
> +bool vfio_external_group_match_file(struct vfio_group *test_group,
> + struct file *filep)
> +{
> + struct vfio_group *group = filep->private_data;
> +
> + return (filep->f_op == &vfio_group_fops) && (group == test_group);
> +}
> +EXPORT_SYMBOL_GPL(vfio_external_group_match_file);
> +
>  int vfio_external_user_iommu_id(struct vfio_group *group)
>  {
>   return iommu_group_id(group->iommu_group);
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index edf9b2cad277..9b34d0af5d27 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -97,6 +97,8 @@ extern void vfio_unregister_iommu_driver(
>   */
>  extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
>  extern void vfio_group_put_external_user(struct vfio_group *group);
> +extern bool vfio_external_group_match_file(struct vfio_group *group,
> +struct file *filep);
>  extern int vfio_external_user_iommu_id(struct vfio_group *group);
>  extern long vfio_external_check_extension(struct vfio_group *group,
> unsigned long arg);
> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
> index db9036ef8c73..7c14729b1f2c 100644
> --- a/virt/kvm/vfio.c
> +++ b/virt/kvm/vfio.c
> @@ -47,6 +47,22 @@ static struct vfio_group 
> *kvm_vfio_group_get_external_user(struct file *filep)
>   return vfio_group;
>  }
>  
> +static bool kvm_vfio_external_group_match_file(struct vfio_group *group,
> +struct file *filep)
> +{
> + bool ret, (*fn)(struct vfio_group *, struct file *);
> +
> + fn = symbol_get(vfio_external_group_match_file);
> + if (!fn)
> + return false;
> +
> + ret = fn(group, filep);
> +
> + symbol_put(vfio_external_group_match_file);
> +
> + return ret;
> +}
> +
>  static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
>  {
>   void (*fn)(struct vfio_group *);
> @@ -186,18 +202,13 @@ static int kvm_vfio_set_group(struct kvm_device *dev, 
> long attr, u64 arg)
>   if (!f.file)
>   return -EBADF;
>  
> - vfio_group = kvm_vfio_group_get_external_user(f.file);
> - fdput(f);
> -
> - if (IS_ERR(vfio_group))
> - return PTR_ERR(vfio_group);
> -
>   ret = -ENOENT;
>  
>   mutex_lock(&kv->lock);
>  
>   list_for_each_entry(kvg, &kv->group_list, node) {
> - if (kvg->vfio_group != vfio_group)
> + if (!kvm_vfio_external_group_match_file(kvg->vfio_group,
> + f.file))
>   continue;
>  
>   list_del(&kvg->node);
> @@ -211,7 +222,7 @@ static int kvm_vfio_set_group(struct kvm_device *dev, 
> long attr, u64 arg)
>  
>   mutex_unlock(&kv->lock);
>  
> - kvm_vfio_group_put_external_user(vfio_group);
> + fdput(f);
>  
>   kvm_vfio_update_coherency(dev);
>  
>

Re: [PATCH 3/7] vfio: New external user group/file match

2017-06-12 Thread Paolo Bonzini 


On 09/06/2017 23:59, Alex Williamson wrote:
> At the point where the kvm-vfio pseudo device wants to release its
> vfio group reference, we can't always acquire a new reference to make
> that happen.  The group can be in a state where we wouldn't allow a
> new reference to be added.  This new helper function allows a caller
> to match a file to a group to facilitate this.  Given a file and
> group, report if they match.  Thus the caller needs to already have a
> group reference to match to the file.  This allows the deletion of a
> group without acquiring a new reference.
> 
> Signed-off-by: Alex Williamson 
> Cc: Paolo Bonzini 
> ---
>  drivers/vfio/vfio.c  |9 +
>  include/linux/vfio.h |2 ++
>  virt/kvm/vfio.c  |   27 +++
>  3 files changed, 30 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
> index f2e24d5699f2..e6117de60f87 100644
> --- a/drivers/vfio/vfio.c
> +++ b/drivers/vfio/vfio.c
> @@ -1776,6 +1776,15 @@ void vfio_group_put_external_user(struct vfio_group 
> *group)
>  }
>  EXPORT_SYMBOL_GPL(vfio_group_put_external_user);
>  
> +bool vfio_external_group_match_file(struct vfio_group *test_group,
> + struct file *filep)
> +{
> + struct vfio_group *group = filep->private_data;
> +
> + return (filep->f_op == &vfio_group_fops) && (group == test_group);
> +}
> +EXPORT_SYMBOL_GPL(vfio_external_group_match_file);
> +
>  int vfio_external_user_iommu_id(struct vfio_group *group)
>  {
>   return iommu_group_id(group->iommu_group);
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index edf9b2cad277..9b34d0af5d27 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -97,6 +97,8 @@ extern void vfio_unregister_iommu_driver(
>   */
>  extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
>  extern void vfio_group_put_external_user(struct vfio_group *group);
> +extern bool vfio_external_group_match_file(struct vfio_group *group,
> +struct file *filep);
>  extern int vfio_external_user_iommu_id(struct vfio_group *group);
>  extern long vfio_external_check_extension(struct vfio_group *group,
> unsigned long arg);
> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
> index db9036ef8c73..7c14729b1f2c 100644
> --- a/virt/kvm/vfio.c
> +++ b/virt/kvm/vfio.c
> @@ -47,6 +47,22 @@ static struct vfio_group 
> *kvm_vfio_group_get_external_user(struct file *filep)
>   return vfio_group;
>  }
>  
> +static bool kvm_vfio_external_group_match_file(struct vfio_group *group,
> +struct file *filep)
> +{
> + bool ret, (*fn)(struct vfio_group *, struct file *);
> +
> + fn = symbol_get(vfio_external_group_match_file);
> + if (!fn)
> + return false;
> +
> + ret = fn(group, filep);
> +
> + symbol_put(vfio_external_group_match_file);
> +
> + return ret;
> +}
> +
>  static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
>  {
>   void (*fn)(struct vfio_group *);
> @@ -186,18 +202,13 @@ static int kvm_vfio_set_group(struct kvm_device *dev, 
> long attr, u64 arg)
>   if (!f.file)
>   return -EBADF;
>  
> - vfio_group = kvm_vfio_group_get_external_user(f.file);
> - fdput(f);
> -
> - if (IS_ERR(vfio_group))
> - return PTR_ERR(vfio_group);
> -
>   ret = -ENOENT;
>  
>   mutex_lock(&kv->lock);
>  
>   list_for_each_entry(kvg, &kv->group_list, node) {
> - if (kvg->vfio_group != vfio_group)
> + if (!kvm_vfio_external_group_match_file(kvg->vfio_group,
> + f.file))
>   continue;
>  
>   list_del(&kvg->node);
> @@ -211,7 +222,7 @@ static int kvm_vfio_set_group(struct kvm_device *dev, 
> long attr, u64 arg)
>  
>   mutex_unlock(&kv->lock);
>  
> - kvm_vfio_group_put_external_user(vfio_group);
> + fdput(f);
>  
>   kvm_vfio_update_coherency(dev);
>  
> 

Reviewed-by: Paolo Bonzini

[PATCH 3/7] vfio: New external user group/file match

2017-06-09 Thread Alex Williamson 
At the point where the kvm-vfio pseudo device wants to release its
vfio group reference, we can't always acquire a new reference to make
that happen.  The group can be in a state where we wouldn't allow a
new reference to be added.  This new helper function allows a caller
to match a file to a group to facilitate this.  Given a file and
group, report if they match.  Thus the caller needs to already have a
group reference to match to the file.  This allows the deletion of a
group without acquiring a new reference.

Signed-off-by: Alex Williamson 
Cc: Paolo Bonzini 
---
 drivers/vfio/vfio.c  |9 +
 include/linux/vfio.h |2 ++
 virt/kvm/vfio.c  |   27 +++
 3 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index f2e24d5699f2..e6117de60f87 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1776,6 +1776,15 @@ void vfio_group_put_external_user(struct vfio_group 
*group)
 }
 EXPORT_SYMBOL_GPL(vfio_group_put_external_user);
 
+bool vfio_external_group_match_file(struct vfio_group *test_group,
+   struct file *filep)
+{
+   struct vfio_group *group = filep->private_data;
+
+   return (filep->f_op == &vfio_group_fops) && (group == test_group);
+}
+EXPORT_SYMBOL_GPL(vfio_external_group_match_file);
+
 int vfio_external_user_iommu_id(struct vfio_group *group)
 {
return iommu_group_id(group->iommu_group);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index edf9b2cad277..9b34d0af5d27 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -97,6 +97,8 @@ extern void vfio_unregister_iommu_driver(
  */
 extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
 extern void vfio_group_put_external_user(struct vfio_group *group);
+extern bool vfio_external_group_match_file(struct vfio_group *group,
+  struct file *filep);
 extern int vfio_external_user_iommu_id(struct vfio_group *group);
 extern long vfio_external_check_extension(struct vfio_group *group,
  unsigned long arg);
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index db9036ef8c73..7c14729b1f2c 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -47,6 +47,22 @@ static struct vfio_group 
*kvm_vfio_group_get_external_user(struct file *filep)
return vfio_group;
 }
 
+static bool kvm_vfio_external_group_match_file(struct vfio_group *group,
+  struct file *filep)
+{
+   bool ret, (*fn)(struct vfio_group *, struct file *);
+
+   fn = symbol_get(vfio_external_group_match_file);
+   if (!fn)
+   return false;
+
+   ret = fn(group, filep);
+
+   symbol_put(vfio_external_group_match_file);
+
+   return ret;
+}
+
 static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
 {
void (*fn)(struct vfio_group *);
@@ -186,18 +202,13 @@ static int kvm_vfio_set_group(struct kvm_device *dev, 
long attr, u64 arg)
if (!f.file)
return -EBADF;
 
-   vfio_group = kvm_vfio_group_get_external_user(f.file);
-   fdput(f);
-
-   if (IS_ERR(vfio_group))
-   return PTR_ERR(vfio_group);
-
ret = -ENOENT;
 
mutex_lock(&kv->lock);
 
list_for_each_entry(kvg, &kv->group_list, node) {
-   if (kvg->vfio_group != vfio_group)
+   if (!kvm_vfio_external_group_match_file(kvg->vfio_group,
+   f.file))
continue;
 
list_del(&kvg->node);
@@ -211,7 +222,7 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long 
attr, u64 arg)
 
mutex_unlock(&kv->lock);
 
-   kvm_vfio_group_put_external_user(vfio_group);
+   fdput(f);
 
kvm_vfio_update_coherency(dev);