Re: [PATCH 8/9] firmware: arm_ffa: Setup and register all the KVM managed partitions

Jonathan Cameron
2020-09-01T16:37:46Z

On Sat, 29 Aug 2020 18:09:22 +0100
Sudeep Holla <sudeep.holla@arm.com> wrote:

> Parse the FFA nodes from the device-tree and register all the partitions
> managed by the KVM hypervisor.
>
> All the partitions including the host(self) are registered as the
> character device with a set of file operations. Most of the interface
> will concentrated in the ioctl.
>
> For now, we have a tiny set of initial ioctls implemented.
>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

A few trivial comments inline.

> ---
> drivers/firmware/arm_ffa/bus.c | 2 +
> drivers/firmware/arm_ffa/driver.c | 378 +++++++++++++++++++++++++++++-
> include/linux/arm_ffa.h | 3 +
> include/uapi/linux/arm_ffa.h | 56 +++++
> 4 files changed, 438 insertions(+), 1 deletion(-)
> create mode 100644 include/uapi/linux/arm_ffa.h
>

...

> diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> index 3670ba400f89..96113e594db6 100644
> --- a/drivers/firmware/arm_ffa/driver.c
> +++ b/drivers/firmware/arm_ffa/driver.c
> @@ -22,11 +22,17 @@
> #define DRIVER_NAME "ARM FF-A"
> #define pr_fmt(fmt) DRIVER_NAME ": " fmt
>
> +#include <linux/arm_ffa.h>
> #include <linux/bitfield.h>
> +#include <linux/device.h>
> +#include <linux/fs.h>
> #include <linux/io.h>
> #include <linux/module.h>
> +#include <linux/of.h>
> #include <linux/slab.h>
> -#include <linux/arm_ffa.h>

Ah. Fix that in the earlier patch rather than adding then moving it.

> +#include <linux/uaccess.h>
> +#include <linux/uuid.h>
> +#include <uapi/linux/arm_ffa.h>
>
> #include "common.h"
>

...

> +
> +static long ffa_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
> +{
> + long r = -EINVAL;
> + void __user *argp = (void __user *)arg;
> + struct ffa_device *ffa_dev = filp->private_data;
> +
> + switch (ioctl) {
> + case FFA_GET_API_VERSION:
> + if (arg)
> + goto out;

Perhaps more readable (and a little shorter) with early returns?

> + r = drv_info->version;
> + break;
> + case FFA_GET_PARTITION_ID:
> + if (arg)
> + goto out;
> + r = ffa_dev->vm_id;
> + break;
> + case FFA_GET_PARTITION_INFO: {
> + struct ffa_partition_info pbuf;
> + struct ffa_part_info __user *pinfo = argp;
> + struct ffa_part_info info;
> + unsigned int count;
> +
> + r = -EFAULT;
> + if (copy_from_user(&info, pinfo, sizeof(info)))
> + break;
> + count = ffa_partition_probe(info.uuid_str, &pbuf);
> + if (count > 1) {
> + r = -E2BIG;
> + break;
> + }
> + r = -EFAULT;
> + if (copy_to_user(pinfo, &info, sizeof(info)))
> + break;
> + r = 0;
> + break;
> + }
> + case FFA_SEND_RECEIVE_SYNC: {
> + struct ffa_send_recv_sync __user *udata = argp;
> + struct ffa_send_recv_sync kdata;
> +
> + r = -EFAULT;
> + if (copy_from_user(&kdata, udata, sizeof(kdata)))
> + break;
> + r = ffa_msg_send_direct_req(ffa_dev->vm_id, kdata.endpoint_id,
> + &kdata.data);
> + if (r)
> + break;
> + if (copy_to_user(udata, &kdata, sizeof(kdata)))
> + break;
> + break;
> + }
> + case FFA_SEND_RECEIVE_ASYNC: {
> + struct ffa_send_recv_async __user *udata = argp;
> + struct ffa_send_recv_async kdata;
> + void *buf;
> +
> + r = -EFAULT;
> + if (copy_from_user(&kdata, udata, sizeof(kdata)))
> + break;
> +
> + if (kdata.length < 0 || kdata.length > RXTX_BUFFER_SIZE) {
> + r = -EINVAL;
> + break;
> + }
> +
> + buf = kzalloc(kdata.length, GFP_KERNEL);
> + if (!buf) {
> + r = -ENOMEM;
> + break;
> + }
> +
> + if (copy_from_user(buf, udata->buffer, kdata.length)) {
> + kfree(buf);
> + break;
> + }
> +
> + r = ffa_msg_send(ffa_dev->vm_id, kdata.endpoint_id, buf,
> + kdata.length);
> + if (r) {
> + kfree(buf);
> + break;
> + }
> +
> + break;
> + }
> + default:
> + r = -EINVAL;
> + }
> +out:
> + return r;
> +}
> +

...

> static int __init ffa_init(void)
> {
> int ret;
> @@ -262,6 +623,14 @@ static int __init ffa_init(void)
> mutex_init(&drv_info->rx_lock);
> mutex_init(&drv_info->tx_lock);
>
> + /* This will be default device both in theguests and host */

the guests

> + ret = ffa_device_alloc_register("self", drv_info->vm_id, NULL);
> + if (ret)
> + return ret;
> +
> + /* Set up all the partitions that KVM hypervisor maintains */
> + ffa_setup_partitions();
> +
> return 0;
> free_pages:
> if (drv_info->tx_buffer)
> @@ -275,6 +644,13 @@ module_init(ffa_init);
>
> static void __exit ffa_exit(void)
> {
> + struct list_head *p;
> +
> + mutex_lock(&ffa_devs_list_mutex);
> + list_for_each(p, &ffa_devs_list)
> + ffa_device_unregister(list_to_ffa_dev(p));
> + mutex_unlock(&ffa_devs_list_mutex);
> +
> ffa_rxtx_unmap(drv_info->vm_id);
> free_pages_exact(drv_info->tx_buffer, RXTX_BUFFER_SIZE);
> free_pages_exact(drv_info->rx_buffer, RXTX_BUFFER_SIZE);

...

Jonathan