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From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: julien.grall@citrix.com, xen-devel@lists.xensource.com,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: [PATCH v8 03/10] xen/arm: inflight irqs during migration
Date: Thu, 24 Jul 2014 17:49:27 +0100	[thread overview]
Message-ID: <alpine.DEB.2.02.1407241748190.2293@kaball.uk.xensource.com> (raw)
In-Reply-To: <1406220497.8706.17.camel@kazak.uk.xensource.com>

On Thu, 24 Jul 2014, Ian Campbell wrote:
> On Thu, 2014-07-24 at 17:45 +0100, Stefano Stabellini wrote:
> > > Are you sure about the second physical IRQ always hitting on the source
> > > pCPU though? I'm unclear about where the physical ITARGETSR gets written
> > > in the scheme you are proposing.
> > 
> > It gets written right away if there are no inflight irqs.
> 
> There's no way that something can be pending in the physical GIC at this
> point? i.e. because it happened since we took the trap?

If it is pending is OK: ARM ARM states that writes to itarget affect
pending irqs too. Only active irqs are not affected. But we deal with
that case separately.


> >  Otherwise it
> > gets written when clearing the LRs. That's why we are sure it is going
> > to hit the old cpu. If the vcpu gets descheduled after EOIing the irq,
> > that is also fine because Xen is going to clear the LRs on hypervisor
> > entry.
> 
> Ian.
> 

  reply	other threads:[~2014-07-24 16:49 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-10 18:12 [PATCH v8 00/10] gic and vgic fixes and improvements Stefano Stabellini
2014-07-10 18:13 ` [PATCH v8 01/10] xen/arm: observe itargets setting in vgic_enable_irqs and vgic_disable_irqs Stefano Stabellini
2014-07-11 13:01   ` Julien Grall
2014-07-23 15:31     ` Stefano Stabellini
2014-07-10 18:13 ` [PATCH v8 02/10] xen/arm: move setting GIC_IRQ_GUEST_QUEUED earlier Stefano Stabellini
2014-07-10 18:13 ` [PATCH v8 03/10] xen/arm: inflight irqs during migration Stefano Stabellini
2014-07-17 12:44   ` Ian Campbell
2014-07-23 14:45     ` Stefano Stabellini
2014-07-23 15:38       ` Ian Campbell
2014-07-24 14:48         ` Stefano Stabellini
2014-07-24 16:41           ` Ian Campbell
2014-07-24 16:45             ` Stefano Stabellini
2014-07-24 16:48               ` Ian Campbell
2014-07-24 16:49                 ` Stefano Stabellini [this message]
2014-07-25  9:08                   ` Ian Campbell
2014-07-10 18:13 ` [PATCH v8 04/10] xen/arm: support irq delivery to vcpu > 0 Stefano Stabellini
2014-07-10 18:13 ` [PATCH v8 05/10] xen/arm: physical irq follow virtual irq Stefano Stabellini
2014-07-11 13:07   ` Julien Grall
2014-07-23 15:00     ` Stefano Stabellini
2014-07-10 18:13 ` [PATCH v8 06/10] xen: introduce sched_move_irqs Stefano Stabellini
2014-07-10 18:13 ` [PATCH v8 07/10] xen/arm: remove workaround to inject evtchn_irq on irq enable Stefano Stabellini
2014-07-11 13:10   ` Julien Grall
2014-07-17 12:50   ` Ian Campbell
2014-07-23 15:04     ` Stefano Stabellini
2014-07-23 16:09       ` Stefano Stabellini
2014-07-23 16:11         ` Ian Campbell
2014-07-23 16:12           ` Stefano Stabellini
2014-07-23 16:16             ` Ian Campbell
2014-07-24 14:37               ` Stefano Stabellini
2014-07-10 18:13 ` [PATCH v8 08/10] xen/arm: take the rank lock before accessing ipriority Stefano Stabellini
2014-07-17 12:51   ` Ian Campbell
2014-07-23 14:57     ` Stefano Stabellini
2014-07-10 18:13 ` [PATCH v8 09/10] xen: introduce bit access macros for the IRQ line status flags Stefano Stabellini
2014-07-11 13:15   ` Julien Grall
2014-07-23 14:52     ` Stefano Stabellini
2014-07-10 18:13 ` [PATCH v8 10/10] xen/arm: make accesses to desc->status flags atomic Stefano Stabellini
2014-07-17 12:52   ` Ian Campbell

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