linux-kernel - Re: [PATCH v3 2/2] iommu/vt-d:Add support for probing ACPI device in RMRR

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Date:   Tue, 1 Sep 2020 14:12:34 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     FelixCuioc <FelixCui-oc@...oxin.com>,
        Joerg Roedel <joro@...tes.org>,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        David Woodhouse <dwmw2@...radead.org>,
        Dan Carpenter <dan.carpenter@...cle.com>, kbuild@...ts.01.org
Cc:     baolu.lu@...ux.intel.com, CobeChen-oc@...oxin.com,
        RaymondPang-oc@...oxin.com, TonyWWang-oc@...oxin.com
Subject: Re: [PATCH v3 2/2] iommu/vt-d:Add support for probing ACPI device in
 RMRR

Hi Felix,

On 8/27/20 6:02 PM, FelixCuioc wrote:
> After acpi device in RMRR is detected,it is necessary
> to establish a mapping for these devices.
> In acpi_device_create_direct_mappings(),create a mapping
> for the acpi device in RMRR.
> Add a helper to achieve the acpi namespace device can
> access the RMRR region.

Are those ACPI devices visible to kernel? If so, any device driver bound
for it?

Best regards,
baolu

> 
> Signed-off-by: FelixCuioc <FelixCui-oc@...oxin.com>
> ---
>   drivers/iommu/intel/iommu.c | 29 +++++++++++++++++++++++++++++
>   drivers/iommu/iommu.c       |  6 ++++++
>   include/linux/iommu.h       |  3 +++
>   3 files changed, 38 insertions(+)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 208a91605288..51d7a5b18f41 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -4799,6 +4799,21 @@ static int __init platform_optin_force_iommu(void)
>   	return 1;
>   }
>   
> +static int acpi_device_create_direct_mappings(struct device *pn_dev, struct device *acpi_device)
> +{
> +	struct iommu_group *group;
> +
> +	acpi_device->bus->iommu_ops = &intel_iommu_ops;
> +	group = iommu_group_get(pn_dev);
> +	if (!group) {
> +		pr_warn("ACPI name space devices create direct mappings wrong!\n");
> +		return -EINVAL;
> +	}
> +	__acpi_device_create_direct_mappings(group, acpi_device);
> +
> +	return 0;
> +}
> +
>   static int __init probe_acpi_namespace_devices(void)
>   {
>   	struct dmar_drhd_unit *drhd;
> @@ -4813,6 +4828,7 @@ static int __init probe_acpi_namespace_devices(void)
>   			struct acpi_device_physical_node *pn;
>   			struct iommu_group *group;
>   			struct acpi_device *adev;
> +			struct device *pn_dev = NULL;
>   
>   			if (dev->bus != &acpi_bus_type)
>   				continue;
> @@ -4823,6 +4839,7 @@ static int __init probe_acpi_namespace_devices(void)
>   					    &adev->physical_node_list, node) {
>   				group = iommu_group_get(pn->dev);
>   				if (group) {
> +					pn_dev = pn->dev;
>   					iommu_group_put(group);
>   					continue;
>   				}
> @@ -4831,7 +4848,19 @@ static int __init probe_acpi_namespace_devices(void)
>   				ret = iommu_probe_device(pn->dev);
>   				if (ret)
>   					break;
> +				pn_dev = pn->dev;
> +			}
> +			if (!pn_dev) {
> +				dev->bus->iommu_ops = &intel_iommu_ops;
> +				ret = iommu_probe_device(dev);
> +				if (ret) {
> +					pr_err("acpi_device probe fail! ret:%d\n", ret);
> +					goto unlock;
> +				}
> +				goto unlock;
>   			}
> +			ret = acpi_device_create_direct_mappings(pn_dev, dev);
> +unlock:
>   			mutex_unlock(&adev->physical_node_lock);
>   
>   			if (ret)
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 609bd25bf154..4f714a2d5ef7 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -779,6 +779,12 @@ static bool iommu_is_attach_deferred(struct iommu_domain *domain,
>   	return false;
>   }
>   
> +void  __acpi_device_create_direct_mappings(struct iommu_group *group, struct device *acpi_device)
> +{
> +	iommu_create_device_direct_mappings(group, acpi_device);
> +}
> +EXPORT_SYMBOL_GPL(__acpi_device_create_direct_mappings);
> +
>   /**
>    * iommu_group_add_device - add a device to an iommu group
>    * @group: the group into which to add the device (reference should be held)
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index fee209efb756..9be134775886 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -514,6 +514,9 @@ extern void iommu_domain_window_disable(struct iommu_domain *domain, u32 wnd_nr)
>   extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev,
>   			      unsigned long iova, int flags);
>   
> +extern void __acpi_device_create_direct_mappings(struct iommu_group *group,
> +						struct device *acpi_device);
> +
>   static inline void iommu_flush_tlb_all(struct iommu_domain *domain)
>   {
>   	if (domain->ops->flush_iotlb_all)
>