[PATCH] drm/amdkfd: clamp queue size to minimum

[David Yat Sin]

If queue size is less than minimum, clamp it to minimum to prevent
underflow when writing queue mqd.

Signed-off-by: David Yat Sin <david.yat...@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 4 ++++
 include/uapi/linux/kfd_ioctl.h           | 2 ++
 2 files changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index 433de9e9a77e..e90c3d1c8f8a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -212,6 +212,8 @@ static int set_queue_properties_from_user(struct 
queue_properties *q_properties,
                return -EINVAL;
        }
 
+       args->ring_size = max(args->ring_size, KFD_MIN_QUEUE_RING_SIZE);
+
        if (!access_ok((const void __user *) args->read_pointer_address,
                        sizeof(uint32_t))) {
                pr_err("Can't access read pointer\n");
@@ -461,6 +463,8 @@ static int kfd_ioctl_update_queue(struct file *filp, struct 
kfd_process *p,
                return -EINVAL;
        }
 
+       args->ring_size = max(args->ring_size, KFD_MIN_QUEUE_RING_SIZE);
+
        properties.queue_address = args->ring_base_address;
        properties.queue_size = args->ring_size;
        properties.queue_percent = args->queue_percentage & 0xFF;
diff --git a/include/uapi/linux/kfd_ioctl.h b/include/uapi/linux/kfd_ioctl.h
index fa9f9846b88e..b0160b09987c 100644
--- a/include/uapi/linux/kfd_ioctl.h
+++ b/include/uapi/linux/kfd_ioctl.h
@@ -62,6 +62,8 @@ struct kfd_ioctl_get_version_args {
 #define KFD_MAX_QUEUE_PERCENTAGE       100
 #define KFD_MAX_QUEUE_PRIORITY         15
 
+#define KFD_MIN_QUEUE_RING_SIZE                1024
+
 struct kfd_ioctl_create_queue_args {
        __u64 ring_base_address;        /* to KFD */
        __u64 write_pointer_address;    /* from KFD */
-- 
2.17.1