Re: [PATCH 0/5] iommu/arm-smmu: Support maintaining bootloader mappings

Vinod Koul
2020-07-09T07:33:40Z

On 08-07-20, 22:01, Bjorn Andersson wrote:
> Based on previous attempts and discussions this is the latest attempt at
> inheriting stream mappings set up by the bootloader, for e.g. boot splash or
> efifb.
>
> The first patch is an implementation of Robin's suggestion that we should just
> mark the relevant stream mappings as BYPASS. Relying on something else to set
> up the stream mappings wanted - e.g. by reading it back in platform specific
> implementation code.
>
> The series then tackles the problem seen in most versions of Qualcomm firmware,
> that the hypervisor intercepts BYPASS writes and turn them into FAULTs. It does
> this by allocating context banks for identity domains as well, with translation
> disabled.
>
> Lastly it amends the stream mapping initialization code to allocate a specific
> identity domain that is used for any mappings inherited from the bootloader, if
> above Qualcomm quirk is required.
>
>
> The series has been tested and shown to allow booting SDM845, SDM850, SM8150,
> SM8250 with boot splash screen setup by the bootloader. Specifically it also
> allows the Lenovo Yoga C630 to boot with SMMU and efifb enabled.

This resolves issue on RB3 for me so:

Tested-by: Vinod Koul <vkoul@kernel.org>

--
~Vinod