Re: [Xen-devel] [PATCH v3 16/16] xen/arm: arm64: Document Cortex-A57 erratum 834220

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 22 Jun 2016, Julien Grall wrote:
> Hi Stefano,
> 
> On 22/06/16 11:08, Stefano Stabellini wrote:
> > On Tue, 7 Jun 2016, Julien Grall wrote:
> > > The ARM erratum applies to certain revisions of Cortex-A57. The
> > > processor may report a Stage 2 translation fault as the result of
> > > Stage 1 fault for load crossing a page boundary when there is a
> > > permission fault or device memory fault at stage 1 and a translation
> > > fault at Stage 2.
> > > 
> > > So Xen needs to check that Stage 1 translation does not generate a fault
> > > before handling the Stage 2 fault. If it is a Stage 1 translation fault,
> > > return to the guest to let the processor injecting the correct fault.
> >                            ^let the process inject (let somebody do
> > something)
> > 
> > 
> > > Only document it as this is already the behavior of the fault handlers.
> > > Note that some optimization could be done to avoid unnecessary translation
> > > fault. This is because HPFAR_EL2 is valid for more use case. For the
> > > moment,
> > > the code is left unmodified.
> > > 
> > > Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> > 
> > Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> 
> I have another series coming up which require to implement a workaround for
> the erratum.
> 
> Given this is only documentation, I am planning to drop this patch from the
> series.

All right

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