From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH for-4.5] xen/arm: clear UIE on hypervisor entry Date: Wed, 19 Nov 2014 13:25:52 -0500 Message-ID: <20141119182552.GA14861@laptop.dumpdata.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Stefano Stabellini Cc: Julien Grall , xen-devel@lists.xensource.com, Ian Campbell , andrii.tseglytskyi@globallogic.com List-Id: xen-devel@lists.xenproject.org On Wed, Nov 19, 2014 at 05:44:49PM +0000, Stefano Stabellini wrote: > UIE being set can cause maintenance interrupts to occur when Xen writes > to one or more LR registers. The effect is a busy loop around the > interrupt handler in Xen > (http://marc.info/?l=xen-devel&m=141597517132682): everything gets stuck. > > Konrad, this fixes an actual bug, at least on OMAP5. It should have no > bad side effects on any other platforms as far as I can tell. It should > go in 4.5. Have you checked (aka ran the tests) on the other platforms? > > Signed-off-by: Stefano Stabellini > Tested-by: Andrii Tseglytskyi ^^^^^^^ 'Reported-and-Tested-by' > > diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c > index 70d10d6..df140b9 100644 > --- a/xen/arch/arm/gic.c > +++ b/xen/arch/arm/gic.c > @@ -403,6 +403,8 @@ void gic_clear_lrs(struct vcpu *v) > if ( is_idle_vcpu(v) ) > return; > > + gic_hw_ops->update_hcr_status(GICH_HCR_UIE, 0); > + > spin_lock_irqsave(&v->arch.vgic.lock, flags); > > while ((i = find_next_bit((const unsigned long *) &this_cpu(lr_mask), > @@ -527,8 +529,6 @@ void gic_inject(void) > > if ( !list_empty(¤t->arch.vgic.lr_pending) && lr_all_full() ) > gic_hw_ops->update_hcr_status(GICH_HCR_UIE, 1); > - else > - gic_hw_ops->update_hcr_status(GICH_HCR_UIE, 0); > } > > static void do_sgi(struct cpu_user_regs *regs, enum gic_sgi sgi)