Re: [PATCH 09/14] platform/x86/intel/ifs: Use generic microcode headers and functions

[Sohil Mehta]

On 10/21/2022 1:34 PM, Jithu Joseph wrote:
> Newer IFS test image headers will use  microcode_header_intel->hdrver = 2,
> so as to distinguish it from microcode images and older IFS test images.

IIUC, older IFS test images would no longer be supported. Have they been 
released publicly?

What would happen if someone tries to load one? I am guessing one of the 
error checks would catch it. It might be useful to describe this error 
signature in the commit message.

>   
> -	if ((data_size + MC_HEADER_SIZE > total_size) || (total_size % sizeof(u32))) {
> -		dev_err(dev, "bad ifs data file size.\n");
> +	if (data->hdrver != IFS_HEADER_VER) {
> +		dev_err(dev, "Header version %d not supported\n", data->hdrver);
>   		return -EINVAL;
>   	}
>   
> -	if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
> -		dev_err(dev, "invalid/unknown ifs update format.\n");
> +	if (microcode_intel_sanity_check((void *)data, true, IFS_HEADER_VER)) {

I referred to this in a another patch. The data->hdrver is already 
verified above, why is there a need to pass it as a parameter as well.

> +		dev_err(dev, "sanity check failed\n");
>   		return -EINVAL;
>   	}
>   
> -	mc = (u32 *)mc_header;
> -	sum = 0;
> -	for (int i = 0; i < total_size / sizeof(u32); i++)
> -		sum += mc[i];
> +	intel_cpu_collect_info(&uci);
>   
> -	if (sum) {
> -		dev_err(dev, "bad ifs data checksum, aborting.\n");
> +	if (!microcode_intel_find_matching_signature((void *)data,
> +						     uci.cpu_sig.sig,
> +						     uci.cpu_sig.pf)) {
> +		dev_err(dev, "cpu signature, pf not matching\n");

What does pf stand for? It would be good to avoid abbreviations for 
error logging.


>   /*
>    * Load ifs image. Before loading ifs module, the ifs image must be located
>    * in /lib/firmware/intel/ifs and named as {family/model/stepping}.{testname}.
> @@ -252,12 +189,11 @@ int ifs_load_firmware(struct device *dev)
>   		goto done;
>   	}
>   
> -	if (!ifs_image_sanity_check(dev, (struct microcode_header_intel *)fw->data)) {
> -		dev_err(dev, "ifs header sanity check failed\n");
> +	ret = ifs_image_sanity_check(dev, (struct microcode_header_intel *)fw->data);
> +	if (ret)
>   		goto release;
> -	}
>   
> -	ifs_header_ptr = (struct ifs_header *)fw->data;
> +	ifs_header_ptr = (struct microcode_header_intel *)fw->data;

The use of a global ifs_header_ptr seems problematic. The semaphore 
operation before calling ifs_load_firmware() makes it seem concurrency 
is expected. Can ifs_load_firmware() really be called concurrently?

If that is not true can we use a mutex for synchronization?

Sohil