Re: [Xen-devel] [PATCH v8 7/7] vtd: add lookup_page method to iommu_ops

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: 13 September 2018 15:51
> To: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
> Cc: George Dunlap <George.Dunlap@xxxxxxxxxx>; Wei Liu
> <wei.liu2@xxxxxxxxxx>; Kevin Tian <kevin.tian@xxxxxxxxx>; xen-devel <xen-
> devel@xxxxxxxxxxxxxxxxxxxx>
> Subject: RE: [PATCH v8 7/7] vtd: add lookup_page method to iommu_ops
> 
> >>> On 13.09.18 at 16:04, <Paul.Durrant@xxxxxxxxxx> wrote:
> >>  -----Original Message-----
> >> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> >> Sent: 13 September 2018 14:57
> >> To: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
> >> Cc: George Dunlap <George.Dunlap@xxxxxxxxxx>; Wei Liu
> >> <wei.liu2@xxxxxxxxxx>; Kevin Tian <kevin.tian@xxxxxxxxx>; xen-devel
> <xen-
> >> devel@xxxxxxxxxxxxxxxxxxxx>
> >> Subject: RE: [PATCH v8 7/7] vtd: add lookup_page method to iommu_ops
> >>
> >> >>> On 13.09.18 at 15:50, <Paul.Durrant@xxxxxxxxxx> wrote:
> >> > Ok. I'll spell it out in the header if you think it is non-obvious.
> >>
> >> Obvious or not - do we _have_ any such outer locking in place right
> now?
> >>
> >
> > Yes. The locking is either via the P2M or grant table locks for all
> current
> > uses or map and unmap that I can see.
> 
> But two different locks still means no guarantees at all.
> 

So, are you saying the current implementation is not fit for purpose? Do you 
want me to add locking at the wrapper level?

  Paul

> Jan
> 


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