From: Marcelo Tosatti <mtosatti@redhat.com>
To: Sheng Yang <sheng@linux.intel.com>
Cc: Amit Shah <amshah@redhat.com>, Avi Kivity <avi@redhat.com>,
kvm@vger.kernel.org, Amit Shah <amit.shah@redhat.com>,
"Han, Weidong" <weidong.han@intel.com>
Subject: Re: [PATCH 15/15] KVM: Fix racy in kvm_free_assigned_irq
Date: Thu, 1 Jan 2009 22:10:37 -0200 [thread overview]
Message-ID: <20090102001037.GA5835@amt.cnet> (raw)
In-Reply-To: <200812311343.55772.sheng@linux.intel.com>
On Wed, Dec 31, 2008 at 01:43:54PM +0800, Sheng Yang wrote:
> On Wednesday 31 December 2008 00:45:51 Marcelo Tosatti wrote:
> > On Tue, Dec 30, 2008 at 10:14:09AM +0800, Sheng Yang wrote:
> > > > There is one remaining issue: kvm_assigned_dev_interrupt_work_handler
> > > > can re-enable the interrupt for KVM_ASSIGNED_DEV_GUEST_MSI case.
> > > > Perhaps you need a new flag to indicate shutdown (so the host IRQ won't
> > > > be reenabled).
> > >
> > > Is it already covered by disable_irq_no_sync() before cancel_work_sync()?
> > > I've noted this in my comment: the irq may be disabled nested(once for
> > > MSI and twice for INTx), but I think it's fine for we're going to free
> > > it.
> >
> > The problem is that the irq can be re-enabled in
> > kvm_assigned_dev_interrupt_work_handler:
> >
> >
> > context 1 | context 2
> >
> > disable_irq_nosync
> > kvm_assigned_dev_interrupt_work_handler
> > enable_irq
> > cancel_work_sync
> >
> > free_irq
> >
>
> Um... My understanding is a little different...
>
> Before context1 execute disable_irq_nosync(), in irq handler,
> disable_irq_nosync() would also been executed. So only one enable_irq() is not
> really enable irq here, which can cover the window at all. That's what I means
> nested disable irq...
You're right. There have been two disable_irq calls.
OK, looks good to me.
next prev parent reply other threads:[~2009-01-02 0:10 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-25 9:09 [PATCH 0/15] Device assignment & MSI enhancement Sheng Yang
2008-12-25 9:09 ` [PATCH 01/15] KVM: Add MSI_ACTION flag for assigned irq Sheng Yang
2008-12-25 9:09 ` [PATCH 02/15] KVM: Use kvm_free_assigned_irq() for free irq Sheng Yang
2008-12-25 9:09 ` [PATCH 03/15] KVM: Add support to disable MSI for assigned device Sheng Yang
2008-12-25 9:09 ` [PATCH 04/15] KVM: Add a route layer to convert MSI message to GSI Sheng Yang
2008-12-25 9:09 ` [PATCH 05/15] KVM: Using gsi_msg mapping for MSI device assignment Sheng Yang
2008-12-25 9:09 ` [PATCH 06/15] KVM: Improve MSI dispatch function Sheng Yang
2008-12-25 9:09 ` [PATCH 07/15] KVM: Using ioapic_irqchip() macro for kvm_set_irq Sheng Yang
2008-12-25 9:09 ` [PATCH 08/15] KVM: Merge MSI handling to kvm_set_irq Sheng Yang
2008-12-25 9:09 ` [PATCH 09/15] KVM: Split IOAPIC structure Sheng Yang
2008-12-25 9:09 ` [PATCH 10/15] KVM: Unified the delivery of IOAPIC and MSI Sheng Yang
2008-12-25 9:09 ` [PATCH 11/15] KVM: Change API of kvm_ioapic_get_delivery_bitmask Sheng Yang
2008-12-25 9:09 ` [PATCH 12/15] KVM: Update intr delivery func to accept unsigned long* bitmap Sheng Yang
2008-12-25 9:09 ` [PATCH 13/15] KVM: bit ops for deliver_bitmap Sheng Yang
2008-12-25 9:09 ` [PATCH 14/15] KVM: Using kfifo for irq recording Sheng Yang
2008-12-26 2:29 ` [PATCH 14/15] KVM: Replace host_irq_disable with a new flag Sheng Yang
2008-12-25 9:09 ` [PATCH 15/15] KVM: Fix racy in kvm_free_assigned_irq Sheng Yang
2008-12-25 11:56 ` Sheng Yang
2008-12-26 2:30 ` Sheng Yang
2008-12-27 20:06 ` Marcelo Tosatti
2008-12-27 20:15 ` Marcelo Tosatti
2008-12-28 11:24 ` Sheng Yang
2008-12-28 12:57 ` Avi Kivity
2008-12-29 5:42 ` Amit Shah
2008-12-29 12:23 ` Sheng Yang
2008-12-29 13:37 ` Avi Kivity
2008-12-29 13:49 ` Sheng Yang
2008-12-29 15:20 ` Marcelo Tosatti
2008-12-30 2:14 ` Sheng Yang
2008-12-30 16:45 ` Marcelo Tosatti
2008-12-31 5:43 ` Sheng Yang
2009-01-02 0:10 ` Marcelo Tosatti [this message]
2009-01-05 7:07 ` Sheng Yang
2009-01-05 13:27 ` Avi Kivity
2009-01-06 1:25 ` Sheng Yang
2008-12-29 13:20 ` Avi Kivity
2008-12-25 9:13 ` [PATCH 0/15] Device assignment & MSI enhancement Sheng Yang
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