From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762568Ab2FVQPK (ORCPT ); Fri, 22 Jun 2012 12:15:10 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:20975 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762509Ab2FVQPI (ORCPT ); Fri, 22 Jun 2012 12:15:08 -0400 X-IronPort-AV: E=Sophos;i="4.77,459,1336363200"; d="scan'208";a="199722616" From: Stefano Stabellini To: CC: , , , , Stefano Stabellini , Konrad Rzeszutek Wilk Subject: [PATCH WIP 5/6] xen: fix unmask_evtchn for HVM guests Date: Fri, 22 Jun 2012 17:14:44 +0100 Message-ID: <1340381685-22529-5-git-send-email-stefano.stabellini@eu.citrix.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1340381685-22529-1-git-send-email-stefano.stabellini@eu.citrix.com> References: <1340381685-22529-1-git-send-email-stefano.stabellini@eu.citrix.com> MIME-Version: 1.0 Content-Type: text/plain 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 irq to be re-enabled. That is because x86 pv guests overwrite the irq_enable pvops with xen_irq_enable_direct that also handles pending events. However x86 HVM guests and ARM guests do not change or do not have the irq_enable pvop, so this scheme doesn't work properly for them. Considering that having a pending irq when unmask_evtchn is called is not very common, and it is better to keep the native_irq_enable implementation for HVM guests and ARM guests, the best thing to do is just using the EVTCHNOP_unmask callback (Xen re-injects pending events in response). Considering that this patch fixes a bug on x86 for current PV on HVM guests, I'll resend it separately. Signed-off-by: Stefano Stabellini CC: Konrad Rzeszutek Wilk --- 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 { -- 1.7.2.5 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Stabellini Subject: [PATCH WIP 5/6] xen: fix unmask_evtchn for HVM guests Date: Fri, 22 Jun 2012 17:14:44 +0100 Message-ID: <1340381685-22529-5-git-send-email-stefano.stabellini@eu.citrix.com> References: <1340381685-22529-1-git-send-email-stefano.stabellini@eu.citrix.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1340381685-22529-1-git-send-email-stefano.stabellini@eu.citrix.com> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: xen-devel@lists.xensource.com, Stefano.Stabellini@eu.citrix.com, Ian.Campbell@citrix.com, tim@xen.org, Stefano Stabellini , Konrad Rzeszutek Wilk List-Id: xen-devel@lists.xenproject.org When unmask_evtchn is called, if we already have an event pending, we just set evtchn_pending_sel waiting for irq to be re-enabled. That is because x86 pv guests overwrite the irq_enable pvops with xen_irq_enable_direct that also handles pending events. However x86 HVM guests and ARM guests do not change or do not have the irq_enable pvop, so this scheme doesn't work properly for them. Considering that having a pending irq when unmask_evtchn is called is not very common, and it is better to keep the native_irq_enable implementation for HVM guests and ARM guests, the best thing to do is just using the EVTCHNOP_unmask callback (Xen re-injects pending events in response). Considering that this patch fixes a bug on x86 for current PV on HVM guests, I'll resend it separately. Signed-off-by: Stefano Stabellini CC: Konrad Rzeszutek Wilk --- 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 { -- 1.7.2.5