From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH 1/3] xen: arm: avoid reusing incorrect mappings when walking the p2m. Date: Mon, 14 Jul 2014 19:17:38 +0100 Message-ID: <53C41EC2.8030705@linaro.org> References: <1405355194.31863.2.camel@kazak.uk.xensource.com> <1405355225-4623-1-git-send-email-ian.campbell@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1405355225-4623-1-git-send-email-ian.campbell@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell , xen-devel@lists.xen.org Cc: tim@xen.org, stefano.stabellini@eu.citrix.com List-Id: xen-devel@lists.xenproject.org Hi Ian, On 07/14/2014 05:27 PM, Ian Campbell wrote: > If we handle a change in a superpage then we need to invalidate any cached > mappings further down, otherwise we risk using them because their offset might > match but be based on a different offset further up the table. > > Signed-off-by: Ian Campbell > --- > xen/arch/arm/p2m.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c > index c0c011a..917baa3 100644 > --- a/xen/arch/arm/p2m.c > +++ b/xen/arch/arm/p2m.c > @@ -719,6 +719,8 @@ static int apply_p2m_changes(struct domain *d, > goto out; > } > cur_first_page = p2m_first_level_index(addr); > + /* Any mapping further down is now invalid */ > + cur_second_offset = ~0; I think you miss to invalid cur_first_offset. Also, I think we have the same issue on Xen 4.4. Regards, -- Julien Grall