Re: [PATCH v4 12/18] nitro_enclaves: Add logic for enclave start

[Alexander Graf <graf@amazon.de>]

On 22.06.20 22:03, Andra Paraschiv wrote:
> After all the enclave resources are set, the enclave is ready for
> beginning to run.
> 
> Add ioctl command logic for starting an enclave after all its resources,
> memory regions and CPUs, have been set.
> 
> The enclave start information includes the local channel addressing -
> vsock CID - and the flags associated with the enclave.
> 
> Signed-off-by: Alexandru Vasile <lexnv@amazon.com>
> Signed-off-by: Andra Paraschiv <andraprs@amazon.com>
> ---
> Changelog
> 
> v3 -> v4
> 
> * Use dev_err instead of custom NE log pattern.
> * Update the naming for the ioctl command from metadata to info.
> * Check for minimum enclave memory size.
> 
> v2 -> v3
> 
> * Remove the WARN_ON calls.
> * Update static calls sanity checks.
> 
> v1 -> v2
> 
> * Add log pattern for NE.
> * Check if enclave state is init when starting an enclave.
> * Remove the BUG_ON calls.
> ---
>   drivers/virt/nitro_enclaves/ne_misc_dev.c | 114 ++++++++++++++++++++++
>   1 file changed, 114 insertions(+)
> 
> diff --git a/drivers/virt/nitro_enclaves/ne_misc_dev.c b/drivers/virt/nitro_enclaves/ne_misc_dev.c
> index 17ccb6cdbd75..d9794f327169 100644
> --- a/drivers/virt/nitro_enclaves/ne_misc_dev.c
> +++ b/drivers/virt/nitro_enclaves/ne_misc_dev.c
> @@ -703,6 +703,45 @@ static int ne_set_user_memory_region_ioctl(struct ne_enclave *ne_enclave,
>   	return rc;
>   }
>   
> +/**
> + * ne_start_enclave_ioctl - Trigger enclave start after the enclave resources,
> + * such as memory and CPU, have been set.
> + *
> + * This function gets called with the ne_enclave mutex held.
> + *
> + * @ne_enclave: private data associated with the current enclave.
> + * @enclave_start_info: enclave info that includes enclave cid and flags.
> + *
> + * @returns: 0 on success, negative return value on failure.
> + */
> +static int ne_start_enclave_ioctl(struct ne_enclave *ne_enclave,
> +	struct ne_enclave_start_info *enclave_start_info)
> +{
> +	struct ne_pci_dev_cmd_reply cmd_reply = {};
> +	struct enclave_start_req enclave_start_req = {};
> +	int rc = -EINVAL;
> +
> +	enclave_start_req.enclave_cid = enclave_start_info->enclave_cid;
> +	enclave_start_req.flags = enclave_start_info->flags;
> +	enclave_start_req.slot_uid = ne_enclave->slot_uid;

I think it's easier to read if you do the initialization straight in the 
variable declaation:

   struct enclave_start_req enclave_start_req = {
     .enclave_cid = enclave_start_info->cid,
     .flags = enclave_start_info->flags,
     .slot_uid = ne_enclave->slot_uid,
   };

> +
> +	rc = ne_do_request(ne_enclave->pdev, ENCLAVE_START, &enclave_start_req,
> +			   sizeof(enclave_start_req), &cmd_reply,
> +			   sizeof(cmd_reply));
> +	if (rc < 0) {
> +		dev_err_ratelimited(ne_misc_dev.this_device,
> +				    "Error in enclave start [rc=%d]\n", rc);
> +
> +		return rc;
> +	}
> +
> +	ne_enclave->state = NE_STATE_RUNNING;
> +
> +	enclave_start_info->enclave_cid = cmd_reply.enclave_cid;
> +
> +	return 0;
> +}
> +
>   static long ne_enclave_ioctl(struct file *file, unsigned int cmd,
>   			     unsigned long arg)
>   {
> @@ -818,6 +857,81 @@ static long ne_enclave_ioctl(struct file *file, unsigned int cmd,
>   		return rc;
>   	}
>   
> +	case NE_START_ENCLAVE: {
> +		struct ne_enclave_start_info enclave_start_info = {};
> +		int rc = -EINVAL;
> +
> +		if (copy_from_user(&enclave_start_info, (void *)arg,
> +				   sizeof(enclave_start_info))) {
> +			dev_err_ratelimited(ne_misc_dev.this_device,
> +					    "Error in copy from user\n");

No need to print anything here

> +
> +			return -EFAULT;
> +		}
> +
> +		mutex_lock(&ne_enclave->enclave_info_mutex);
> +
> +		if (ne_enclave->state != NE_STATE_INIT) {
> +			dev_err_ratelimited(ne_misc_dev.this_device,
> +					    "Enclave isn't in init state\n");
> +
> +			mutex_unlock(&ne_enclave->enclave_info_mutex);
> +
> +			return -EINVAL;

Can this be its own return value instead?

> +		}
> +
> +		if (!ne_enclave->nr_mem_regions) {
> +			dev_err_ratelimited(ne_misc_dev.this_device,
> +					    "Enclave has no mem regions\n");
> +
> +			mutex_unlock(&ne_enclave->enclave_info_mutex);
> +
> +			return -ENOMEM;
> +		}
> +
> +		if (ne_enclave->mem_size < NE_MIN_ENCLAVE_MEM_SIZE) {
> +			dev_err_ratelimited(ne_misc_dev.this_device,
> +					    "Enclave memory is less than %ld\n",
> +					    NE_MIN_ENCLAVE_MEM_SIZE);
> +
> +			mutex_unlock(&ne_enclave->enclave_info_mutex);
> +
> +			return -ENOMEM;
> +		}
> +
> +		if (!ne_enclave->nr_vcpus) {
> +			dev_err_ratelimited(ne_misc_dev.this_device,
> +					    "Enclave has no vcpus\n");
> +
> +			mutex_unlock(&ne_enclave->enclave_info_mutex);
> +
> +			return -EINVAL;

Same here.

> +		}
> +
> +		if (!cpumask_empty(ne_enclave->cpu_siblings)) {
> +			dev_err_ratelimited(ne_misc_dev.this_device,
> +					    "CPU siblings not used\n");
> +
> +			mutex_unlock(&ne_enclave->enclave_info_mutex);
> +
> +			return -EINVAL;

Same here.

> +		}
> +
> +		rc = ne_start_enclave_ioctl(ne_enclave, &enclave_start_info);
> +
> +		mutex_unlock(&ne_enclave->enclave_info_mutex);
> +
> +		if (copy_to_user((void *)arg, &enclave_start_info,

This needs to be __user void *, no?


Alex

> +				 sizeof(enclave_start_info))) {
> +			dev_err_ratelimited(ne_misc_dev.this_device,
> +					    "Error in copy to user\n");
> +
> +			return -EFAULT;
> +		}
> +
> +		return rc;
> +	}
> +
>   	default:
>   		return -ENOTTY;
>   	}
> 



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