Re: [Xen-devel] [PATCH] x86/efi: Reserve EFI properties table

[Julien Grall <julien.grall@xxxxxxx>]

Hi Andrew,

On 08/05/17 17:29, Andrew Cooper wrote:
> On 08/05/17 17:17, Ross Lagerwall wrote:
> > Some EFI firmware implementations may place the EFI properties table in
> > RAM marked as BootServicesData, which Xen does not consider as reserved.
> > When dom0 tries to access the EFI properties table (which Linux >= 4.4
> > does), it crashes with a page fault.
> The pagefault is just a side effect of Linux blindly assuming that the
> ioremap() request succeeded.
>
> From Xen's point of view, Dom0 tries to map a page which doesn't belong
> to dom_xen, resulting a permission failure.
>
> >   Fix this by unconditionally
> > marking the EFI properties table as reserved in the E820, much like is
> > done with the dmi regions.
> >
> > Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>
> This is probably also 4.9 material.
It looks like Jan had some comments on this patch. I haven't seen any 
reply from Ross, I will wait before looking from a release perspective.
Cheers,

--
Julien Grall

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