12:22 p.m.
..snip..
+static int handle_mailbox_cmd_from_user(struct cxl_mem *cxlm,
+ const struct cxl_mem_command *cmd,
+ u64 in_payload, u64 out_payload,
+ s32 *size_out, u32 *retval)
+{
+ struct device *dev = &cxlm->pdev->dev;
+ struct mbox_cmd mbox_cmd = {
+ .opcode = cmd->opcode,
+ .size_in = cmd->info.size_in,
+ .size_out = cmd->info.size_out,
+ };
+ int rc;
+
+ if (cmd->info.size_out) {
+ mbox_cmd.payload_out = kvzalloc(cmd->info.size_out, GFP_KERNEL);
+ if (!mbox_cmd.payload_out)
+ return -ENOMEM;
+ }
+
+ if (cmd->info.size_in) {
+ mbox_cmd.payload_in = vmemdup_user(u64_to_user_ptr(in_payload),
+ cmd->info.size_in);
+ if (IS_ERR(mbox_cmd.payload_in))
+ return PTR_ERR(mbox_cmd.payload_in);
Not that this should happen, but what if info.size_out was set? Should
you also free mbox_cmd.payload_out?
+ }
+
+ rc = cxl_mem_mbox_get(cxlm);
+ if (rc)
+ goto out;
+
+ dev_dbg(dev,
+ "Submitting %s command for user\n"
+ "\topcode: %x\n"
+ "\tsize: %ub\n",
+ cxl_command_names[cmd->info.id].name, mbox_cmd.opcode,
+ cmd->info.size_in);
+
+ rc = __cxl_mem_mbox_send_cmd(cxlm, &mbox_cmd);
+ cxl_mem_mbox_put(cxlm);
+ if (rc)
+ goto out;
+
+ /*
+ * @size_out contains the max size that's allowed to be written back out
+ * to userspace. While the payload may have written more output than
+ * this it will have to be ignored.
+ */
+ if (mbox_cmd.size_out) {
+ dev_WARN_ONCE(dev, mbox_cmd.size_out > *size_out,
+ "Invalid return size\n");
+ if (copy_to_user(u64_to_user_ptr(out_payload),
+ mbox_cmd.payload_out, mbox_cmd.size_out)) {
+ rc = -EFAULT;
+ goto out;
+ }
+ }
+
+ *size_out = mbox_cmd.size_out;
+ *retval = mbox_cmd.return_code;
+
+out:
+ kvfree(mbox_cmd.payload_in);
+ kvfree(mbox_cmd.payload_out);
+ return rc;
+}
..snip..
+static int cxl_query_cmd(struct cxl_memdev *cxlmd,
+ struct cxl_mem_query_commands __user *q)
+{
+ struct device *dev = &cxlmd->dev;
+ struct cxl_mem_command *cmd;
+ u32 n_commands;
+ int j = 0;
How come it is 'j' instead of the usual 'i'?
> +
> + dev_dbg(dev, "Query IOCTL\n");
> +
> + if (get_user(n_commands, &q->n_commands))
> + return -EFAULT;
> +
> + /* returns the total number if 0 elements are requested. */
> + if (n_commands == 0)
> + return put_user(cxl_cmd_count, &q->n_commands);
> +
> + /*
> + * otherwise, return max(n_commands, total commands) cxl_command_info
> + * structures.
> + */
> + cxl_for_each_cmd(cmd) {
> + const struct cxl_command_info *info = &cmd->info;
> +
> + if (copy_to_user(&q->commands[j++], info, sizeof(*info)))
> + return -EFAULT;
> +
> + if (j == n_commands)
> + break;
> + }
> +
> + return 0;
> +}
> +