Re: [PATCH v2 3/4] ACPI: scan: Add support for LoongArch in acpi_iommu_configure_id()

[Rafael J. Wysocki (Intel)]

On Fri, Jul 17, 2026 at 8:44 AM Bibo Mao <maobibo@xxxxxxxxxxx> wrote:
>
> acpi_iommu_configure_id() currently supports only IORT and VIOT. Add
> support for IOVT as well.
>
> Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>

The one-liner in scan.c is fine with me, so

Acked-by: Rafael J. Wysocki (Intel) <rafael@xxxxxxxxxx> # ACPI core

for this one, but conditional on the acceptance of the Loongarch-specific parts.

Thanks!

> ---
>  drivers/acpi/loongarch/iovt.c | 61 +++++++++++++++++++++++++++++++++++
>  drivers/acpi/scan.c           |  3 ++
>  include/linux/acpi_iovt.h     | 13 ++++++++
>  3 files changed, 77 insertions(+)
>  create mode 100644 include/linux/acpi_iovt.h
>
> diff --git a/drivers/acpi/loongarch/iovt.c b/drivers/acpi/loongarch/iovt.c
> index fb384664ba78..09fcf09e0f85 100644
> --- a/drivers/acpi/loongarch/iovt.c
> +++ b/drivers/acpi/loongarch/iovt.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: GPL-2.0-only
>
>  #include <linux/acpi.h>
> +#include <linux/acpi_iovt.h>
>  #include <linux/pci.h>
>  #include "init.h"
>
> @@ -217,3 +218,63 @@ void __init acpi_iovt_late_init(void)
>         iovt_init_devices(hdr);
>         acpi_put_table(hdr);
>  }
> +
> +static int iovt_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data)
> +{
> +       u32 sbdf;
> +       struct iovt_fwnode *np;
> +       struct device *aliased_dev = data;
> +       u32 domain = pci_domain_nr(pdev->bus);
> +       struct iovt_device_entry *entry;
> +       bool found = false;
> +
> +       list_for_each_entry(np, &iovt_fwnode_list, list) {
> +               if (domain != np->segment)
> +                       continue;
> +
> +               /* We're not translating ourself */
> +               if (dev_id == np->devid)
> +                       return -EINVAL;
> +
> +               if (np->flag & ACPI_IOVT_MAGAGE_BY_SEGMENT) {
> +                       found = true;
> +                       break;
> +               }
> +
> +               list_for_each_entry(entry, &np->ep_list, list) {
> +                       if (dev_id < entry->start_devid)
> +                               continue;
> +
> +                       if (dev_id > entry->end_devid)
> +                               continue;
> +
> +                       found = true;
> +                       break;
> +               }
> +
> +               if (found)
> +                       break;
> +       }
> +
> +       if (!found)
> +               return -ENODEV;
> +
> +       sbdf = (domain << 16) + dev_id;
> +       return acpi_iommu_fwspec_init(aliased_dev, sbdf, np->fwnode);
> +}
> +
> +/*
> + * iovt_iommu_configure_id - Set-up IOMMU configuration for a device.
> + *
> + * @dev: device to configure
> + * @id_in: optional input id const value pointer
> + *
> + * Returns: 0 on success, <0 on failure
> + */
> +int iovt_iommu_configure_id(struct device *dev, const u32 *id_in)
> +{
> +       if (!dev_is_pci(dev))
> +               return -ENODEV;
> +
> +       return pci_for_each_dma_alias(to_pci_dev(dev), iovt_pci_dev_iommu_init, dev);
> +}
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 9a7ac2eb9ce0..508575f25e10 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -13,6 +13,7 @@
>  #include <linux/kernel.h>
>  #include <linux/acpi.h>
>  #include <linux/acpi_iort.h>
> +#include <linux/acpi_iovt.h>
>  #include <linux/acpi_rimt.h>
>  #include <linux/acpi_viot.h>
>  #include <linux/iommu.h>
> @@ -1629,6 +1630,8 @@ static int acpi_iommu_configure_id(struct device *dev, const u32 *id_in)
>                 err = rimt_iommu_configure_id(dev, id_in);
>         if (err && err != -EPROBE_DEFER)
>                 err = viot_iommu_configure(dev);
> +       if (err && err != -EPROBE_DEFER)
> +               err = iovt_iommu_configure_id(dev, id_in);
>
>         mutex_unlock(&iommu_probe_device_lock);
>
> diff --git a/include/linux/acpi_iovt.h b/include/linux/acpi_iovt.h
> new file mode 100644
> index 000000000000..25a846b96260
> --- /dev/null
> +++ b/include/linux/acpi_iovt.h
> @@ -0,0 +1,13 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#ifndef __ACPI_IOVT_H__
> +#define __ACPI_IOVT_H__
> +
> +#if defined(CONFIG_IOMMU_API) && defined(CONFIG_ACPI_IOVT)
> +int iovt_iommu_configure_id(struct device *dev, const u32 *id_in);
> +#else
> +static inline int iovt_iommu_configure_id(struct device *dev, const u32 *id_in)
> +{ return -ENODEV; }
> +#endif
> +
> +#endif
> --
> 2.39.3
>