From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v6a 17/17] xen/arm: Restrict saving of gic register for idle domain Date: Fri, 27 Jun 2014 15:58:48 +0100 Message-ID: <53AD86A8.5020905@linaro.org> References: <1403760849-14627-1-git-send-email-vijay.kilari@gmail.com> <1403760849-14627-18-git-send-email-vijay.kilari@gmail.com> <53AC2F21.7060800@linaro.org> <1403880347.3169.54.camel@kazak.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1403880347.3169.54.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: vijay.kilari@gmail.com, stefano.stabellini@eu.citrix.com, Prasun.Kapoor@caviumnetworks.com, vijaya.kumar@caviumnetworks.com, tim@xen.org, xen-devel@lists.xen.org, stefano.stabellini@citrix.com List-Id: xen-devel@lists.xenproject.org On 27/06/14 15:45, Ian Campbell wrote: > On Thu, 2014-06-26 at 15:33 +0100, Julien Grall wrote: >> Hi Vijay, >> >> On 06/26/2014 06:34 AM, vijay.kilari@gmail.com wrote: >>> From: Vijaya Kumar K >>> >>> Check for idle domain is missing before saving gic context >> >> Can you be a bit more verbose to explain why we don't need to save >> context for idle vcpu? > > There's lots of state you don't need to save for an idle domain, this > one seems pretty clear cut to me. Right. Actually, for a lambda developer it's not clear why we add non-stop is_idle_vcpu on every save/restore functions. As the Xen will always stay to hyp mode when the idle VCPU is running, why do we simply skip ctx_to/ctx_from? It would make more sense and we will be able to put a big comment to clearly explain how idle VCPU works. Regards, -- Julien Grall