On Sat, May 4, 2024 at 12:13 AM Tomasz Jeznach <tjeznach@xxxxxxxxxxxx> wrote:
>
> Advertise IOMMU device and its core API.
> Only minimal implementation for single identity domain type, without
> per-group domain protection.
>
> Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Signed-off-by: Tomasz Jeznach <tjeznach@xxxxxxxxxxxx>
> ---
> drivers/iommu/riscv/iommu.c | 66 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 66 insertions(+)
>
> diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
> index 3c5a6b49669d..1f889daffb0e 100644
> --- a/drivers/iommu/riscv/iommu.c
> +++ b/drivers/iommu/riscv/iommu.c
> @@ -17,6 +17,7 @@
> #include <linux/init.h>
> #include <linux/iommu.h>
> #include <linux/kernel.h>
> +#include <linux/pci.h>
>
> #include "iommu-bits.h"
> #include "iommu.h"
> @@ -36,6 +37,60 @@ static void riscv_iommu_disable(struct riscv_iommu_device *iommu)
> riscv_iommu_writel(iommu, RISCV_IOMMU_REG_PQCSR, 0);
> }
>
> +static int riscv_iommu_attach_identity_domain(struct iommu_domain *iommu_domain,
> + struct device *dev)
> +{
> + /* Global pass-through already enabled, do nothing for now. */
> + return 0;
> +}
> +
> +static struct iommu_domain riscv_iommu_identity_domain = {
> + .type = IOMMU_DOMAIN_IDENTITY,
> + .ops = &(const struct iommu_domain_ops) {
> + .attach_dev = riscv_iommu_attach_identity_domain,
> + }
> +};
> +
> +static int riscv_iommu_device_domain_type(struct device *dev)
> +{
> + return IOMMU_DOMAIN_IDENTITY;
> +}
> +
> +static struct iommu_group *riscv_iommu_device_group(struct device *dev)
> +{
> + if (dev_is_pci(dev))
> + return pci_device_group(dev);
> + return generic_device_group(dev);
> +}
> +
> +static int riscv_iommu_of_xlate(struct device *dev, const struct of_phandle_args *args)
> +{
> + return iommu_fwspec_add_ids(dev, args->args, 1);
> +}
> +
> +static struct iommu_device *riscv_iommu_probe_device(struct device *dev)
> +{
> + struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> + struct riscv_iommu_device *iommu;
> +
> + if (!fwspec->iommu_fwnode->dev || !fwspec->num_ids)
> + return ERR_PTR(-ENODEV);
It seems to me that we might need to ensure fwspec is not NULL before
accessing fwspec->iommu_fwnode, otherwise, it will cause NULL pointer
dereference.
> +
> + iommu = dev_get_drvdata(fwspec->iommu_fwnode->dev);
> + if (!iommu)
> + return ERR_PTR(-ENODEV);
> +
> + return &iommu->iommu;
> +}
> +
> +static const struct iommu_ops riscv_iommu_ops = {
> + .of_xlate = riscv_iommu_of_xlate,
> + .identity_domain = &riscv_iommu_identity_domain,
> + .def_domain_type = riscv_iommu_device_domain_type,
> + .device_group = riscv_iommu_device_group,
> + .probe_device = riscv_iommu_probe_device,
> +};
> +
> static int riscv_iommu_init_check(struct riscv_iommu_device *iommu)
> {
> u64 ddtp;
> @@ -71,6 +126,7 @@ static int riscv_iommu_init_check(struct riscv_iommu_device *iommu)
>
> void riscv_iommu_remove(struct riscv_iommu_device *iommu)
> {
> + iommu_device_unregister(&iommu->iommu);
> iommu_device_sysfs_remove(&iommu->iommu);
> }
>
> @@ -95,5 +151,15 @@ int riscv_iommu_init(struct riscv_iommu_device *iommu)
> return dev_err_probe(iommu->dev, rc,
> "cannot register sysfs interface\n");
>
> + rc = iommu_device_register(&iommu->iommu, &riscv_iommu_ops, iommu->dev);
> + if (rc) {
> + dev_err_probe(iommu->dev, rc, "cannot register iommu interface\n");
> + goto err_remove_sysfs;
> + }
> +
> return 0;
> +
> +err_remove_sysfs:
> + iommu_device_sysfs_remove(&iommu->iommu);
> + return rc;
> }
> --
> 2.34.1
>
>
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