On Wed, Jul 16, 2025 at 01:39:47PM +0800, huaqian.li@xxxxxxxxxxx wrote:
> From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
>
> The AM654 lacks an IOMMU, thus does not support isolating DMA requests
> from untrusted PCI devices to selected memory regions this way. Use
> static PVU-based protection instead. The PVU, when enabled, will only
> accept DMA requests that address previously configured regions.
>
> Use the availability of a restricted-dma-pool memory region as trigger
> and register it as valid DMA target with the PVU. In addition, enable
> the mapping of requester IDs to VirtIDs in the PCI RC. Use only a single
> VirtID so far, catching all devices.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Signed-off-by: Li Hua Qian <huaqian.li@xxxxxxxxxxx>
> ---
> drivers/pci/controller/dwc/pci-keystone.c | 106 ++++++++++++++++++++++
> 1 file changed, 106 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
> index 2b2632e513b5..fbf1bf43b7ca 100644
> --- a/drivers/pci/controller/dwc/pci-keystone.c
> +++ b/drivers/pci/controller/dwc/pci-keystone.c
[------------------email has been trimmed----------------------------]
> +static void ks_release_restricted_dma(struct platform_device *pdev)
> +{
> + struct of_phandle_iterator it;
> + struct resource phys;
> + int err;
> +
> + if (!IS_ENABLED(CONFIG_TI_PVU))
> + return;
> +
> + of_for_each_phandle(&it, err, pdev->dev.of_node, "memory-region",
> + NULL, 0) {
> + if (of_device_is_compatible(it.node, "restricted-dma-pool") &&
> + of_address_to_resource(it.node, 0, &phys) == 0) {
> + ti_pvu_remove_region(KS_PCI_VIRTID, &phys);
> + break;
> + }
> + }
> +}
> +
> static int ks_pcie_probe(struct platform_device *pdev)
> {
> const struct dw_pcie_host_ops *host_ops;
> @@ -1284,6 +1384,10 @@ static int ks_pcie_probe(struct platform_device *pdev)
> if (ret < 0)
> goto err_get_sync;
>
> + ret = ks_init_restricted_dma(pdev);
> + if (ret < 0)
> + goto err_get_sync;
> +
Please move the above into the section specific to RC mode. This has
been agreed to by Jan at:
https://lore.kernel.org/r/e9716614-1849-4524-af4d-20587df365cf@xxxxxxxxxxx/
> switch (mode) {
> case DW_PCIE_RC_TYPE:
> if (!IS_ENABLED(CONFIG_PCI_KEYSTONE_HOST)) {
> @@ -1365,6 +1469,8 @@ static void ks_pcie_remove(struct platform_device *pdev)
> int num_lanes = ks_pcie->num_lanes;
> struct device *dev = &pdev->dev;
>
> + ks_release_restricted_dma(pdev);
> +
Regards,
Siddharth.
