[v3,6/8] KVM: kvm-vfio: wrapper to VFIO external API device helpers

Message ID 1416767760-14487-7-git-send-email-eric.auger@linaro.org
State New
Headers show

Commit Message

Auger Eric Nov. 23, 2014, 6:35 p.m.
Provide wrapper functions that allow KVM-VFIO device code to
interact with a vfio device:
- kvm_vfio_device_get_external_user gets a handle to a struct
  vfio_device from the vfio device file descriptor and increments
  its reference counter,
- kvm_vfio_device_put_external_user decrements the reference counter
  to a vfio device,
- kvm_vfio_external_base_device returns a handle to the struct device
  of the vfio device.

The KVM-VFIO device uses the VFIO external API device functions.

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

---

v2 -> v3:
reword the commit message and title

v1 -> v2:
- kvm_vfio_external_get_base_device renamed into
  kvm_vfio_external_base_device
- kvm_vfio_external_get_type removed
---
 arch/arm/include/asm/kvm_host.h |  5 +++++
 virt/kvm/vfio.c                 | 45 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

Comments

Christoffer Dall Nov. 30, 2014, 1:01 p.m. | #1
On Sun, Nov 23, 2014 at 07:35:58PM +0100, Eric Auger wrote:
> Provide wrapper functions that allow KVM-VFIO device code to
> interact with a vfio device:
> - kvm_vfio_device_get_external_user gets a handle to a struct
>   vfio_device from the vfio device file descriptor and increments
>   its reference counter,
> - kvm_vfio_device_put_external_user decrements the reference counter
>   to a vfio device,
> - kvm_vfio_external_base_device returns a handle to the struct device
>   of the vfio device.
> 
> The KVM-VFIO device uses the VFIO external API device functions.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> 
> v2 -> v3:
> reword the commit message and title
> 
> v1 -> v2:
> - kvm_vfio_external_get_base_device renamed into
>   kvm_vfio_external_base_device
> - kvm_vfio_external_get_type removed
> ---
>  arch/arm/include/asm/kvm_host.h |  5 +++++
>  virt/kvm/vfio.c                 | 45 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 50 insertions(+)
> 
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index 53036e2..bca5b79 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -169,6 +169,11 @@ void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
>  unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu);
>  int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices);
>  
> +struct vfio_device;
> +struct vfio_device *kvm_vfio_device_get_external_user(struct file *filep);
> +void kvm_vfio_device_put_external_user(struct vfio_device *vdev);
> +struct device *kvm_vfio_external_base_device(struct vfio_device *vdev);
> +

why do we add this in kvm_host.h ?

>  /* We do not have shadow page tables, hence the empty hooks */
>  static inline int kvm_age_hva(struct kvm *kvm, unsigned long start,
>  			      unsigned long end)
> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
> index 620e37f..6f0cc34 100644
> --- a/virt/kvm/vfio.c
> +++ b/virt/kvm/vfio.c
> @@ -60,6 +60,51 @@ static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
>  	symbol_put(vfio_group_put_external_user);
>  }
>  
> +struct vfio_device *kvm_vfio_device_get_external_user(struct file *filep)
> +{
> +	struct vfio_device *vdev;
> +	struct vfio_device *(*fn)(struct file *);
> +
> +	fn = symbol_get(vfio_device_get_external_user);
> +	if (!fn)
> +		return ERR_PTR(-EINVAL);
> +
> +	vdev = fn(filep);
> +
> +	symbol_put(vfio_device_get_external_user);
> +
> +	return vdev;
> +}
> +
> +void kvm_vfio_device_put_external_user(struct vfio_device *vdev)
> +{
> +	void (*fn)(struct vfio_device *);
> +
> +	fn = symbol_get(vfio_device_put_external_user);
> +	if (!fn)
> +		return;
> +
> +	fn(vdev);
> +
> +	symbol_put(vfio_device_put_external_user);
> +}
> +
> +struct device *kvm_vfio_external_base_device(struct vfio_device *vdev)
> +{
> +	struct device *(*fn)(struct vfio_device *);
> +	struct device *dev;
> +
> +	fn = symbol_get(vfio_external_base_device);
> +	if (!fn)
> +		return NULL;
> +
> +	dev = fn(vdev);
> +
> +	symbol_put(vfio_external_base_device);
> +
> +	return dev;
> +}
> +
>  static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
>  {
>  	long (*fn)(struct vfio_group *, unsigned long);
> -- 
> 1.9.1
>

Patch

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 53036e2..bca5b79 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -169,6 +169,11 @@  void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
 unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu);
 int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *indices);
 
+struct vfio_device;
+struct vfio_device *kvm_vfio_device_get_external_user(struct file *filep);
+void kvm_vfio_device_put_external_user(struct vfio_device *vdev);
+struct device *kvm_vfio_external_base_device(struct vfio_device *vdev);
+
 /* We do not have shadow page tables, hence the empty hooks */
 static inline int kvm_age_hva(struct kvm *kvm, unsigned long start,
 			      unsigned long end)
diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
index 620e37f..6f0cc34 100644
--- a/virt/kvm/vfio.c
+++ b/virt/kvm/vfio.c
@@ -60,6 +60,51 @@  static void kvm_vfio_group_put_external_user(struct vfio_group *vfio_group)
 	symbol_put(vfio_group_put_external_user);
 }
 
+struct vfio_device *kvm_vfio_device_get_external_user(struct file *filep)
+{
+	struct vfio_device *vdev;
+	struct vfio_device *(*fn)(struct file *);
+
+	fn = symbol_get(vfio_device_get_external_user);
+	if (!fn)
+		return ERR_PTR(-EINVAL);
+
+	vdev = fn(filep);
+
+	symbol_put(vfio_device_get_external_user);
+
+	return vdev;
+}
+
+void kvm_vfio_device_put_external_user(struct vfio_device *vdev)
+{
+	void (*fn)(struct vfio_device *);
+
+	fn = symbol_get(vfio_device_put_external_user);
+	if (!fn)
+		return;
+
+	fn(vdev);
+
+	symbol_put(vfio_device_put_external_user);
+}
+
+struct device *kvm_vfio_external_base_device(struct vfio_device *vdev)
+{
+	struct device *(*fn)(struct vfio_device *);
+	struct device *dev;
+
+	fn = symbol_get(vfio_external_base_device);
+	if (!fn)
+		return NULL;
+
+	dev = fn(vdev);
+
+	symbol_put(vfio_external_base_device);
+
+	return dev;
+}
+
 static bool kvm_vfio_group_is_coherent(struct vfio_group *vfio_group)
 {
 	long (*fn)(struct vfio_group *, unsigned long);