From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: Frame buffer mmap not working in pvops dom0
Date: Wed, 21 Jul 2010 15:50:06 -0400
Message-ID: <20100721195006.GA5839@phenom.dumpdata.com>
References: <4C46FA8D.6040809@tycho.nsa.gov>
	<20100721141613.GG17817@reaktio.net>
	<20100721144209.GA5031@phenom.dumpdata.com>
	<4C4711BB.5090905@tycho.nsa.gov>
	<20100721190056.GA9756@phenom.dumpdata.com>
	<4C474909.8080005@tycho.nsa.gov>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Return-path: <xen-devel-bounces@lists.xensource.com>
Content-Disposition: inline
In-Reply-To: <4C474909.8080005@tycho.nsa.gov>
List-Unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
List-Id: xen-devel@lists.xenproject.org

> The code path is fb_mmap with a NULL fbops->fb_mmap, so it just
> delegates to the default code. Specifically, io_remap_pfn_range is where
> the bad mapping is requested.
> 
> I have a patch that fixes the issue, but I'm not sure under what
> conditions the _PAGE_IOMAP bit needs to be set.

Oh wow. That easy, eh?

> --- a/arch/x86/include/asm/fb.h
> +++ b/arch/x86/include/asm/fb.h
> @@ -10,6 +10,7 @@ static inline void fb_pgprotect
>  {
>         if (boot_cpu_data.x86 > 3)
>                 pgprot_val(vma->vm_page_prot) |= _PAGE_PCD;
> +       pgprot_val(vma->vm_page_prot) |= _PAGE_IOMAP;
>  }
> 
>  #ifdef CONFIG_X86_32


I would say this patch is more sensible as the VM_IO flag had been
set already, it just never got propagated:


diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index 731fce6..187171b 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1362,6 +1362,7 @@ fb_mmap(struct file *file, struct vm_area_struct * vma)
 	vma->vm_pgoff = off >> PAGE_SHIFT;
 	/* This is an IO map - tell maydump to skip this VMA */
 	vma->vm_flags |= VM_IO | VM_RESERVED;
+	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 	fb_pgprotect(file, vma, off);
 	if (io_remap_pfn_range(vma, vma->vm_start, off >> PAGE_SHIFT,
 			     vma->vm_end - vma->vm_start, vma->vm_page_prot))


If that fixes your problem, are you OK with me sticking a Signed-off-by:
from you on this patch?