From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Stabellini Subject: Re: [PATCH v4 07/10] xen/arm: call gic_clear_lrs on entry to the hypervisor Date: Fri, 21 Mar 2014 16:34:59 +0000 Message-ID: References: <1395232325-19226-7-git-send-email-stefano.stabellini@eu.citrix.com> <1395407692.19839.59.camel@kazak.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1395407692.19839.59.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, jtd@galois.com, xen-devel@lists.xensource.com, Stefano Stabellini List-Id: xen-devel@lists.xenproject.org On Fri, 21 Mar 2014, Ian Campbell wrote: > On Wed, 2014-03-19 at 12:32 +0000, Stefano Stabellini wrote: > > Can this not be folded back into the patch which added this function? Yes, it can. > > This change is needed by other patches later on. It is going to make > > sure that the calculation in Xen of the highest priority interrupt > > currently inflight is correct and accurate and not based on stale data. > > Hrm, can we not do this on demand just at the point where we are about > to make such a calculation? There are going to be lots of hypervisor > entries which don't want to do anything at all with interrupts, aren't > there? The alternative would be calling gic_clear_lrs at the beginning of gic_inject and gic_events_need_delivery, that is called by local_events_need_delivery*. It could be called multiple times before returning to guest. However gic_clear_lrs only iterates over the LRs in lr_mask, so even calling it multiple times shouldn't cause more work, the only slow down would be due to the spin_lock.