From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762234Ab2FVQ0c (ORCPT ); Fri, 22 Jun 2012 12:26:32 -0400 Received: from smtp.eu.citrix.com ([62.200.22.115]:45046 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753136Ab2FVQ0a (ORCPT ); Fri, 22 Jun 2012 12:26:30 -0400 X-IronPort-AV: E=Sophos;i="4.77,459,1336348800"; d="scan'208";a="13175139" Date: Fri, 22 Jun 2012 17:26:07 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: "linux-kernel@vger.kernel.org" CC: "xen-devel@lists.xensource.com" , Stefano Stabellini , Stefano Stabellini , Konrad Rzeszutek Wilk Subject: [PATCH] xen/events: fix unmask_evtchn for PV on HVM guests In-Reply-To: <1340381685-22529-1-git-send-email-stefano.stabellini@eu.citrix.com> Message-ID: References: <1340381685-22529-1-git-send-email-stefano.stabellini@eu.citrix.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When unmask_evtchn is called, if we already have an event pending, we just set evtchn_pending_sel waiting for local_irq_enable to be called. That is because PV guests set the irq_enable pvops to xen_irq_enable_direct that also handles pending events. However HVM guests (and ARM guests) do not change or do not have the irq_enable pvop, so evtchn_unmask cannot work properly for them. Considering that having the pending_irq bit set when unmask_evtchn is called is not very common, and it is simpler to keep the native_irq_enable implementation for HVM guests (and ARM guests), the best thing to do is just use the EVTCHNOP_unmask hypercall (Xen re-injects pending events in response). Signed-off-by: Stefano Stabellini --- drivers/xen/events.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/xen/events.c b/drivers/xen/events.c index eae0d0b..0132505 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -372,8 +372,11 @@ static void unmask_evtchn(int port) BUG_ON(!irqs_disabled()); - /* Slow path (hypercall) if this is a non-local port. */ - if (unlikely(cpu != cpu_from_evtchn(port))) { + /* Slow path (hypercall) if this is a non-local port or if this is + * an hvm domain and an event is pending (hvm domains don't have + * their own implementation of irq_enable). */ + if (unlikely((cpu != cpu_from_evtchn(port)) || + (xen_hvm_domain() && sync_test_bit(port, &s->evtchn_pending[0])))) { struct evtchn_unmask unmask = { .port = port }; (void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask); } else {