On Mon, Sep 13, 2021, at 20:25, Marc Zyngier wrote:
> The MSI doorbell on Apple HW can be any address in the low 4GB
> range. However, the MSI write is matched by the PCIe block before
> hitting the iommu. It must thus be excluded from the IOVA range
> that is assigned to any PCIe device.
>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
It's not pretty but I'm not aware of any better solution and this should
work as long as these two are always paired. With the small nit below
addressed:
Reviewed-by: Sven Peter <sven@xxxxxxxxxxxxx>
> ---
> drivers/iommu/apple-dart.c | 25 +++++++++++++++++++++++++
> drivers/pci/controller/Kconfig | 5 +++++
> drivers/pci/controller/pcie-apple.c | 4 +++-
> 3 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
> index 559db9259e65..d1456663688e 100644
> --- a/drivers/iommu/apple-dart.c
> +++ b/drivers/iommu/apple-dart.c
> @@ -721,6 +721,29 @@ static int apple_dart_def_domain_type(struct device *dev)
> return 0;
> }
>
> +#define DOORBELL_ADDR (CONFIG_PCIE_APPLE_MSI_DOORBELL_ADDR & PAGE_MASK)
> +
> +static void apple_dart_get_resv_regions(struct device *dev,
> + struct list_head *head)
> +{
> +#ifdef CONFIG_PCIE_APPLE
I think using IS_ENABLED would be better here in case the pcie driver is built as
a module which would then only define CONFIG_PCIE_APPLE_MODULE AIUI.
Thanks,
Sven
