[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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



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.

Regards,

--
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel

 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.