Subject: Re: [PATCH] cxl: Fix is_page_fault() for POWER9

From: Vaibhav Jain <[email-masked]>
Date: Thu, 06 Jul 2017 16:38:11 +0530

Christophe Lombard <[email-masked]> writes:

> This patches removes this restriction and all page faults, whatever the
> reason, will be handled. In this case, the interruption is always
> acknowledged.

This can also be done with adding call to cxl_ack_ae(ctx) at the end of
cxl_handle_fault().

>  static bool cxl_is_page_fault(struct cxl_context *ctx, u64 dsisr)
>  {
> -	u64 crs; /* Translation Checkout Response Status */
> -
>  	if ((cxl_is_power8()) && (dsisr & CXL_PSL_DSISR_An_DM))
>  		return true;
>
> -	if (cxl_is_power9()) {
> -		crs = (dsisr & CXL_PSL9_DSISR_An_CO_MASK);
> -		if ((crs == CXL_PSL9_DSISR_An_PF_SLR) ||
> -		    (crs == CXL_PSL9_DSISR_An_PF_RGC) ||
> -		    (crs == CXL_PSL9_DSISR_An_PF_RGP) ||
> -		    (crs == CXL_PSL9_DSISR_An_PF_HRH) ||
> -		    (crs == CXL_PSL9_DSISR_An_PF_STEG) ||
> -		    (crs == CXL_PSL9_DSISR_An_URTCH)) {
> -			return true;
> -		}
> -	}
Removing this check will force call to copro_handle_mm_fault even for
nmmu reported errors that only need to be communicated to the AFU and
not handled by mm subsystem as such. 

> +	if (cxl_is_power9())
> +		return true;

Optional: With this change the function has become a good candidate for
being inlined or even converting to a macro.

-- 
Vaibhav Jain <[email-masked]>
Linux Technology Center, IBM India Pvt. Ltd.