svn commit: r290130 - head/sys/dev/ntb/ntb_hw

[Konstantin Belousov]

On Thu, Oct 29, 2015 at 04:16:28AM +0000, Conrad E. Meyer wrote:
> Author: cem
> Date: Thu Oct 29 04:16:28 2015
> New Revision: 290130
> URL: https://svnweb.freebsd.org/changeset/base/290130
> 
> Log:
>   ntb: Do not attempt to set write-combining on MWs
>   
>   AMD64 pmap assumes ranges will be in the DMAP, which isn't necessarily
>   true for NTB memory windows (especially 64-bit BARs).
I am not sure what do you mean.  pmap_change_attr() handles either DMAP
or kernel mapped memory.

>   
>   Suggested by:	pmap_change_attr_locked -> kassert_panic
>   Sponsored by:	EMC / Isilon Storage Division
> 
> Modified:
>   head/sys/dev/ntb/ntb_hw/ntb_hw.c
> 
> Modified: head/sys/dev/ntb/ntb_hw/ntb_hw.c
> ==============================================================================
> --- head/sys/dev/ntb/ntb_hw/ntb_hw.c	Thu Oct 29 04:16:16 2015	(r290129)
> +++ head/sys/dev/ntb/ntb_hw/ntb_hw.c	Thu Oct 29 04:16:28 2015	(r290130)
> @@ -755,9 +755,13 @@ map_memory_window_bar(struct ntb_softc *
>  		save_bar_parameters(bar);
>  	}
>  
> +#if 0	/* XXX: amd64 pmap_change_attr() assumes region lies in DMAP. */
>  	/* Mark bar region as write combining to improve performance. */
>  	rc = pmap_change_attr((vm_offset_t)bar->vbase, bar->size,
>  	    VM_MEMATTR_WRITE_COMBINING);
> +#else
> +	rc = EINVAL;
> +#endif
>  	print_map_success(ntb, bar, "mw");
>  	if (rc == 0)
>  		device_printf(ntb->device,