From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH] xen/arm: ctxt_switch: Document the erratum #852523 related to Cortex A57 Date: Fri, 9 Oct 2015 10:22:31 +0100 Message-ID: <1444382551.1410.309.camel@citrix.com> References: <1444332157-22325-1-git-send-email-julien.grall@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZkTsv-0000E2-7F for xen-devel@lists.xenproject.org; Fri, 09 Oct 2015 09:22:41 +0000 In-Reply-To: <1444332157-22325-1-git-send-email-julien.grall@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: Julien Grall , xen-devel@lists.xenproject.org Cc: stefano.stabellini@eu.citrix.com List-Id: xen-devel@lists.xenproject.org On Thu, 2015-10-08 at 20:22 +0100, Julien Grall wrote: > When restoring the system register state for an AArch32 guest at EL2, > writes to DACR32_EL2 may not be correctly synchronised by Cortex-A57, > which can lead to the guest effectively running into unexpected domain > faults. > > Thankfully, we don't hit this erratum in Xen. Nonetheless, document the > code to prevent any introduction of the erratum if the context switch > code is re-ordered. > > Link: http://lists.xen.org/archives/html/xen-devel/2015-09/msg01746.html > Signed-off-by: Julien Grall Acked-by: Ian Campbell nits: > > + /* > + * This write to sysreg CONTEXTIDR_EL1 ensure we don't hit the erratum "ensures" and s/the //. (fixable on commit) Ian.