[PATCH v6 01/24] vfio: Allocate per device file structure

Yi Liu
2023-03-08T13:30:35Z

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 <yi.l.liu@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
---
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 27d5ba7cf9dc..af2ef8006e1d 100644
--- a/drivers/vfio/group.c
+++ b/drivers/vfio/group.c
@@ -218,19 +218,26 @@ 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]", &vfio_device_fops,
- device, O_RDWR);
+ df, O_RDWR);
if (IS_ERR(filep)) {
ret = PTR_ERR(filep);
goto err_close_device;
@@ -254,6 +261,8 @@ 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 7b19c621e0e6..87d3dd6b9ef9 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -16,11 +16,17 @@ struct iommufd_ctx;
struct iommu_group;
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 89497c933490..f0b9151e3ba7 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -404,6 +404,20 @@ 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)
{
@@ -517,12 +531,15 @@ 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;
}

@@ -1087,7 +1104,8 @@ 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);
@@ -1114,7 +1132,8 @@ 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 *device = df->device;

if (unlikely(!device->ops->read))
return -EINVAL;
@@ -1126,7 +1145,8 @@ static ssize_t vfio_device_fops_write(struct file *filep,
const 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 *device = df->device;

if (unlikely(!device->ops->write))
return -EINVAL;
@@ -1136,7 +1156,8 @@ static ssize_t vfio_device_fops_write(struct file *filep,

static int vfio_device_fops_mmap(struct file *filep, struct vm_area_struct *vma)
{
- struct vfio_device *device = filep->private_data;
+ struct vfio_device_file *df = filep->private_data;
+ struct vfio_device *device = df->device;

if (unlikely(!device->ops->mmap))
return -EINVAL;
--
2.34.1