From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH -v2] EFI: Runtime services virtual mapping
Date: Mon, 23 Sep 2013 15:08:41 +0800
Message-ID: <20130923070841.GE7007@dhcp-16-126.nay.redhat.com>
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To: Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>
Cc: X86 ML <x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>, Matt Fleming <matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>, Matthew Garrett <mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org>, "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>, James Bottomley <James.Bottomley-d9PhHud1JfjCXq6kfMZ53/egYHeGw8Jk@public.gmane.org>, Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
List-Id: linux-efi@vger.kernel.org

On 09/23/13 at 08:29am, Borislav Petkov wrote:
> On Mon, Sep 23, 2013 at 01:47:41PM +0800, Dave Young wrote:
> > > +	unsigned long size = md->num_pages << PAGE_SHIFT;
> > > +
> > > +	efi_va -= size;
> > > +	if (efi_va < EFI_VA_END) {
> > > +		pr_warning(FW_WARN "VA address range overflow!\n");
> > > +		return;
> > > +	}
> > > +
> > > +	/* Do the 1:1 map */
> > > +	__map_region(md, md->phys_addr);
> > > +
> > > +	/* Do the VA map */
> > > +	__map_region(md, efi_va);
> > 
> > 
> > Could you add comment for above code? It's hard to understand the
> > twice mapping if one did not follow the old thread.
> 
> Does that suffice:
> 
> /*
>  * Make sure the 1:1 mappings are present as a catch-all for b0rked firmware
>  * which doesn't update all internal pointers after switching to virtual mode
>  * and would otherwise crap on us.
>  */
> 
> ?

Yes, looks good. Thanks

> 
> Btw, when you reply to a mail, please remove that quoted portion of it
> which you're not replying to - I had to scroll a bunch of screens down
> and I almost missed your reply. :)

Will do. I did notice the problem after I enter 'y' in mutt, sorry about it.

> 
> Thanks.
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> Sent from a fat crate under my desk. Formatting is fine.
> --