Re: [Xen-devel] [PATCH v4 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization

["Xu, Quan" <quan.xu@xxxxxxxxx>]

On March 11, 2016 8:24am, <Tian, Kevin> wrote:
> > From: Xu, Quan
> > Sent: Thursday, March 10, 2016 10:10 PM
> >
> > pcidevs_lock doesn't require interrupts to be disabled while being acquired.
> > However there remains an exception in AMD IOMMU code, where the lock
> > is acquired with interrupt disabled. This inconsistency might lead to 
> > deadlock.
> >
> > The fix is straightforward to use spin_lock instead. Also interrupt
> > has been enabled when this function is invoked, so we're sure
> > consistency around pcidevs_lock can be guaranteed after this fix.
> >
> > Signed-off-by: Quan Xu <quan.xu@xxxxxxxxx>
> > Reviewed-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
> > CC: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> > CC: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
> > CC: Jan Beulich <jbeulich@xxxxxxxx>
> > CC: Kevin Tian <kevin.tian@xxxxxxxxx>
> 
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>

Kevin, thanks!!
Quan

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