Re: [Intel-gfx] [PATCH v5 01/19] vfio: Allocate per device file structure

[Jason Gunthorpe]

On Mon, Feb 27, 2023 at 03:11:17AM -0800, Yi Liu wrote:
> This is preparation for adding vfio device cdev support. vfio device
> cdev requires:
> 1) a per device file memory to store the kvm pointer set by KVM. It will
>be propagated to vfio_device:kvm after the device cdev file is bound
>to an iommufd
> 2) a mechanism to block device access through device cdev fd before it
>is bound to an iommufd
> 
> To address above requirements, this adds a per device file structure
> named vfio_device_file. For now, it's only a wrapper of struct vfio_device
> pointer. Other fields will be added to this per file structure in future
> commits.
> 
> Signed-off-by: Yi Liu 
> Reviewed-by: Kevin Tian 
> Reviewed-by: Eric Auger 
> ---
>  drivers/vfio/group.c | 13 +++--
>  drivers/vfio/vfio.h  |  6 ++
>  drivers/vfio/vfio_main.c | 31 ++-
>  3 files changed, 43 insertions(+), 7 deletions(-)

Reviewed-by: Jason Gunthorpe 

Jason

[Intel-gfx] [PATCH v5 01/19] vfio: Allocate per device file structure

[Yi Liu]

This is preparation for adding vfio device cdev support. vfio device
cdev requires:
1) a per device file memory to store the kvm pointer set by KVM. It will
   be propagated to vfio_device:kvm after the device cdev file is bound
   to an iommufd
2) a mechanism to block device access through device cdev fd before it
   is bound to an iommufd

To address above requirements, this adds a per device file structure
named vfio_device_file. For now, it's only a wrapper of struct vfio_device
pointer. Other fields will be added to this per file structure in future
commits.

Signed-off-by: Yi Liu 
Reviewed-by: Kevin Tian 
Reviewed-by: Eric Auger 
---
 drivers/vfio/group.c | 13 +++--
 drivers/vfio/vfio.h  |  6 ++
 drivers/vfio/vfio_main.c | 31 ++-
 3 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
index 0e9036e2b9c4..cf51e1a0fd96 100644
--- a/drivers/vfio/group.c
+++ b/drivers/vfio/group.c
@@ -215,19 +215,26 @@ void vfio_device_group_close(struct vfio_device *device)
 
 static struct file *vfio_device_open_file(struct vfio_device *device)
 {
+   struct vfio_device_file *df;
struct file *filep;
int ret;
 
+   df = vfio_allocate_device_file(device);
+   if (IS_ERR(df)) {
+   ret = PTR_ERR(df);
+   goto err_out;
+   }
+
ret = vfio_device_group_open(device);
if (ret)
-   goto err_out;
+   goto err_free;
 
/*
 * We can't use anon_inode_getfd() because we need to modify
 * the f_mode flags directly to allow more than just ioctls
 */
filep = anon_inode_getfile("[vfio-device]", _device_fops,
-  device, O_RDWR);
+  df, O_RDWR);
if (IS_ERR(filep)) {
ret = PTR_ERR(filep);
goto err_close_device;
@@ -251,6 +258,8 @@ static struct file *vfio_device_open_file(struct 
vfio_device *device)
 
 err_close_device:
vfio_device_group_close(device);
+err_free:
+   kfree(df);
 err_out:
return ERR_PTR(ret);
 }
diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index e9721d8424bc..61bbf673e672 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -16,11 +16,17 @@ struct iommu_group;
 struct vfio_device;
 struct vfio_container;
 
+struct vfio_device_file {
+   struct vfio_device *device;
+};
+
 void vfio_device_put_registration(struct vfio_device *device);
 bool vfio_device_try_get_registration(struct vfio_device *device);
 int vfio_device_open(struct vfio_device *device, struct iommufd_ctx *iommufd);
 void vfio_device_close(struct vfio_device *device,
   struct iommufd_ctx *iommufd);
+struct vfio_device_file *
+vfio_allocate_device_file(struct vfio_device *device);
 
 extern const struct file_operations vfio_device_fops;
 
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 3a597e799918..d99fa0cec18e 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -396,6 +396,20 @@ static bool vfio_assert_device_open(struct vfio_device 
*device)
return !WARN_ON_ONCE(!READ_ONCE(device->open_count));
 }
 
+struct vfio_device_file *
+vfio_allocate_device_file(struct vfio_device *device)
+{
+   struct vfio_device_file *df;
+
+   df = kzalloc(sizeof(*df), GFP_KERNEL_ACCOUNT);
+   if (!df)
+   return ERR_PTR(-ENOMEM);
+
+   df->device = device;
+
+   return df;
+}
+
 static int vfio_device_first_open(struct vfio_device *device,
  struct iommufd_ctx *iommufd)
 {
@@ -509,12 +523,15 @@ static inline void vfio_device_pm_runtime_put(struct 
vfio_device *device)
  */
 static int vfio_device_fops_release(struct inode *inode, struct file *filep)
 {
-   struct vfio_device *device = filep->private_data;
+   struct vfio_device_file *df = filep->private_data;
+   struct vfio_device *device = df->device;
 
vfio_device_group_close(device);
 
vfio_device_put_registration(device);
 
+   kfree(df);
+
return 0;
 }
 
@@ -1079,7 +1096,8 @@ static int vfio_ioctl_device_feature(struct vfio_device 
*device,
 static long vfio_device_fops_unl_ioctl(struct file *filep,
   unsigned int cmd, unsigned long arg)
 {
-   struct vfio_device *device = filep->private_data;
+   struct vfio_device_file *df = filep->private_data;
+   struct vfio_device *device = df->device;
int ret;
 
ret = vfio_device_pm_runtime_get(device);
@@ -1106,7 +1124,8 @@ static long vfio_device_fops_unl_ioctl(struct file *filep,
 static ssize_t vfio_device_fops_read(struct file *filep, char __user *buf,
 size_t count, loff_t *ppos)
 {
-   struct vfio_device *device = filep->private_data;
+   struct vfio_device_file *df = filep->private_data;
+   struct vfio_device