WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] [PATCH 4/6] xen-gntdev: Support mapping in HVM domains

To: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH 4/6] xen-gntdev: Support mapping in HVM domains
From: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
Date: Mon, 14 Feb 2011 12:43:10 -0500
Cc: jeremy@xxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxx, Ian.Campbell@xxxxxxxxxx
Delivery-date: Mon, 14 Feb 2011 09:44:06 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20110214155136.GA11034@xxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Organization: National Security Agency
References: <1296753544-13323-1-git-send-email-dgdegra@xxxxxxxxxxxxx> <1296753544-13323-5-git-send-email-dgdegra@xxxxxxxxxxxxx> <20110214155136.GA11034@xxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc13 Thunderbird/3.1.7
On 02/14/2011 10:51 AM, Konrad Rzeszutek Wilk wrote:
>> +static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
>> +
>>  /* ------------------------------------------------------------------ */
>>  
>>  static void gntdev_print_maps(struct gntdev_priv *priv,
>> @@ -179,11 +184,34 @@ static void gntdev_put_map(struct grant_map *map)
>>  
>>      atomic_sub(map->count, &pages_mapped);
>>  
>> -    if (map->pages)
>> +    if (map->pages) {
>> +            if (!use_ptemod)
>> +                    unmap_grant_pages(map, 0, map->count);
> 
> In the past (before this patch) the unmap_grant_pages would be called
> on the .ioctl, .release, and .close (on VMA). This adds it now also
> on the mmu_notifier_ops paths. Why?
> 
This does not actually add the unmap on the mmu_notifier path. The MMU
notifier is used only if use_ptemod is true, and unmap_grant_pages is
only called when use_ptemod is false.

The HVM path for map and unmap is slightly different: HVM keeps the pages
mapped until the area is deleted, while the PV case (use_ptemod being true)
must unmap them when userspace unmaps the range. In the normal use case,
this makes no difference to users since unmap time is deletion time.

-- 
Daniel De Graaf
National Security Agency

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>