From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH] xen: arm: document which hypercalls (and subops) are supported on ARM Date: Mon, 29 Jul 2013 14:09:29 -0400 Message-ID: <20130729180929.GA13280@phenom.dumpdata.com> References: <1374517040-10822-1-git-send-email-ijc@hellion.org.uk> <1374588861.6623.104.camel@hastur.hellion.org.uk> <1374598788.6623.123.camel@hastur.hellion.org.uk> <1375109811.12741.21.camel@kazak.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1375109811.12741.21.camel@kazak.uk.xensource.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 Cc: julien.grall@citrix.com, xen-devel@lists.xen.org, tim@xen.org, Stefano Stabellini List-Id: xen-devel@lists.xenproject.org On Mon, Jul 29, 2013 at 03:56:51PM +0100, Ian Campbell wrote: > On Tue, 2013-07-23 at 17:59 +0100, Ian Campbell wrote: > > On Tue, 2013-07-23 at 16:34 +0100, Stefano Stabellini wrote: > > > On Tue, 23 Jul 2013, Ian Campbell wrote: > > > > On Tue, 2013-07-23 at 12:33 +0100, Stefano Stabellini wrote: > > > > > > > > > You are missing all the common tmem ops. > > > > > > > > tmem_ops are not hooked up in arm_hypercall_table, so they are currently > > > > not supported. We should add them here when we add the necessary > > > > support. ISTR stubbing out some functions which are used by tmem > > > > (steal_page and donate_page perhaps?) so it's not just a case or wiring > > > > it up either. > > > > > > Right.. I was confused by the fact that we do compile tmem_op in Linux, > > > even though XEN_TMEM is actually not available on ARM or ARM64 > > > > I started from the other end and looked at what the hypervisor actually > > implements rather than what Linux calls. It's useful to validate from > > both angles though. For now I think we should stick with documenting > > what the hypervisor provides even if the kernel might try and > > optimistically call other stuff too. > > So did we decide whether to run with this patch or not? I would say a better option is to just disable by default tmem in Xen hypervisor for ARM. So even if you boot with 'tmem=1' nothing will happen. That way when I get an ARM box up and I can test tmem we can just revert that simple patch without much trouble.