Re: [PATCH for-4.14 0/3] Remove the 1GB limitation on Rasberry Pi 4

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Mon, 18 May 2020, Julien Grall wrote:
> From: Julien Grall <jgrall@xxxxxxxxxx>
> 
> Hi all,
> 
> At the moment, a user who wants to boot Xen on the Raspberry Pi 4 can
> only use the first GB of memory.
> 
> This is because several devices cannot DMA above 1GB but Xen doesn't
> necessarily allocate memory for Dom0 below 1GB.
> 
> This small series is trying to address the problem by allowing a
> platform to restrict where Dom0 banks are allocated.
> 
> This is also a candidate for Xen 4.14. Without it, a user will not be
> able to use all the RAM on the Raspberry Pi 4.

The series looks good to me aside from the couple of minor issues being
discussed


> This series has only be slighlty tested. I would appreciate more test on
> the Rasbperry Pi 4 to confirm this removing the restriction.
> 
> Cheers,
> 
> Cc: paul@xxxxxxx
> 
> Julien Grall (3):
>   xen/arm: Allow a platform to override the DMA width
>   xen/arm: Take into account the DMA width when allocating Dom0 memory
>     banks
>   xen/arm: plat: Allocate as much as possible memory below 1GB for dom0
>     for RPI
> 
>  xen/arch/arm/domain_build.c                | 32 +++++++++++++---------
>  xen/arch/arm/platform.c                    |  5 ++++
>  xen/arch/arm/platforms/brcm-raspberry-pi.c |  1 +
>  xen/include/asm-arm/mm.h                   |  2 ++
>  xen/include/asm-arm/numa.h                 |  5 ----
>  xen/include/asm-arm/platform.h             |  2 ++
>  6 files changed, 29 insertions(+), 18 deletions(-)
> 
> -- 
> 2.17.1
>