From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH] xen: workaround for 64-bit size/alignment bitops Date: Mon, 28 Apr 2014 10:10:08 +0100 Message-ID: <535E1AF0.3090402@citrix.com> References: <1398589752-14639-1-git-send-email-murzin.v@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta4.messagelabs.com ([85.158.143.247]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WehZl-00067N-PH for xen-devel@lists.xenproject.org; Mon, 28 Apr 2014 09:10:13 +0000 In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Pranavkumar Sawargaonkar Cc: xen-devel@lists.xenproject.org, Vladimir Murzin , Ian Campbell List-Id: xen-devel@lists.xenproject.org On 28/04/14 09:47, Pranavkumar Sawargaonkar wrote: > On 27 April 2014 14:39, Vladimir Murzin wrote: >> Xen assumes that bit operations are able to operate on 32-bit size and >> alignment. For arm64 bitops are based on atomic exclusive load/store >> instructions to guarantee that changes are made atomically. However, these >> instructions require that address to be aligned to the data size. Because, by >> default, bitops operates on 64-bit size it implies that address should be >> aligned appropriately. All these lead to breakage of Xen assumption for bitops >> properties. >> >> As a workaround address is aligned forcefully along with adjustment for bit >> position. >> [...] > > I have tried this patch on XGENE and works fine, I have managed to get > dom0 and domU working with it. > > Tested-by: Pranavkumar Sawargaonkar Thanks. Are there arm64 platforms that support Xen currently available in 3.15? Or can this wait until 3.16? David