On Fri, 2024-12-13 at 17:49 -0500, Matthew Rosato wrote:
> PCI devices on s390 have a DMA offset that is reported via CLP. In
> preparation for allowing identity domains, setup the bus_dma_region
> for all PCI devices using the reported CLP value.
>
> Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
> ---
> arch/s390/pci/pci_bus.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
> index d5ace00d10f0..14527687d0f2 100644
> --- a/arch/s390/pci/pci_bus.c
> +++ b/arch/s390/pci/pci_bus.c
> @@ -19,6 +19,7 @@
> #include <linux/jump_label.h>
> #include <linux/pci.h>
> #include <linux/printk.h>
> +#include <linux/dma-direct.h>
>
> #include <asm/pci_clp.h>
> #include <asm/pci_dma.h>
> @@ -284,10 +285,27 @@ static struct zpci_bus *zpci_bus_alloc(int topo, bool topo_is_tid)
> return zbus;
> }
>
> +static void pci_dma_range_setup(struct pci_dev *pdev)
> +{
> + struct zpci_dev *zdev = to_zpci(pdev);
> + struct bus_dma_region *map;
> +
> + map = kzalloc(sizeof(*map), GFP_KERNEL);
> + if (!map)
> + return;
> +
> + map->cpu_start = 0;
> + map->dma_start = PAGE_ALIGN(zdev->start_dma);
> + map->size = (u64)virt_to_phys(high_memory);
I don't think we should restrict the size here to the size of memory.
Instead I think it should be zdev->end_dma - zdev->start_dma.
Since we handle the restriction to memory size as reserved regions I
think that should be compatible. Also I think otherwise this might
break the admittedly odd s390_iommu_aperture=X kernel parameter on
LPARs.
> + pdev->dev.dma_range_map = map;
> +}
> +
> void pcibios_bus_add_device(struct pci_dev *pdev)
> {
> struct zpci_dev *zdev = to_zpci(pdev);
>
> + pci_dma_range_setup(pdev);
> +
> /*
> * With pdev->no_vf_scan the common PCI probing code does not
> * perform PF/VF linking.
