Re: [RESEND PATCH] ACPI: VIOT: Initialize the correct IOMMU fwspec

[Eric Auger <eric.auger@redhat.com>]

Hi Jean,

On 3/20/23 19:05, Jean-Philippe Brucker wrote:
> When setting up DMA for a PCI device, we need to initialize its
> iommu_fwspec with all possible alias RIDs (such as PCI bridges). To do
> this we use pci_for_each_dma_alias() which calls
> viot_pci_dev_iommu_init(). This function incorrectly initializes the
> fwspec of the bridge instead of the device being configured. Fix it by
> passing the original device as context to pci_for_each_dma_alias().
>
> Fixes: 3cf485540e7b ("ACPI: Add driver for the VIOT table")
> Reported-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Tested-by: Eric Auger <eric.auger@redhat.com>

With this patch the pcie-to-pci bridge is assigned an iommu group.
The iommu group topology is not yet correct (ie. end points downstream
to the pcie-to-pci bridge are put in a separate iommu group) however
this is not related to that patch and not supposed to be fixed here
(https://lore.kernel.org/all/4fead092-1058-198a-b430-3dee0fffcd51@arm.com/)

Thanks

Eric

> ---
> This fixes issue (1) reported here:
> https://lore.kernel.org/all/Y8qzOKm6kvhGWG1T@myrica/
>
> resend: Added linux-pci list
> ---
>  drivers/acpi/viot.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/viot.c b/drivers/acpi/viot.c
> index ed752cbbe636..c8025921c129 100644
> --- a/drivers/acpi/viot.c
> +++ b/drivers/acpi/viot.c
> @@ -328,6 +328,7 @@ static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data)
>  {
>  	u32 epid;
>  	struct viot_endpoint *ep;
> +	struct device *aliased_dev = data;
>  	u32 domain_nr = pci_domain_nr(pdev->bus);
>  
>  	list_for_each_entry(ep, &viot_pci_ranges, list) {
> @@ -338,7 +339,7 @@ static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data)
>  			epid = ((domain_nr - ep->segment_start) << 16) +
>  				dev_id - ep->bdf_start + ep->endpoint_id;
>  
> -			return viot_dev_iommu_init(&pdev->dev, ep->viommu,
> +			return viot_dev_iommu_init(aliased_dev, ep->viommu,
>  						   epid);
>  		}
>  	}
> @@ -372,7 +373,7 @@ int viot_iommu_configure(struct device *dev)
>  {
>  	if (dev_is_pci(dev))
>  		return pci_for_each_dma_alias(to_pci_dev(dev),
> -					      viot_pci_dev_iommu_init, NULL);
> +					      viot_pci_dev_iommu_init, dev);
>  	else if (dev_is_platform(dev))
>  		return viot_mmio_dev_iommu_init(to_platform_device(dev));
>  	return -ENODEV;