Re: [PATCH v1 2/3] iommu/vt-d: Allocate domain info for real DMA sub-devices

[Lu Baolu <baolu.lu@linux.intel.com>]

On 2020/5/28 0:56, Jon Derrick wrote:
> Sub-devices of a real DMA device might exist on a separate segment than
> the real DMA device and its IOMMU. These devices should still have a
> valid device_domain_info, but the current dma alias model won't
> allocate info for the subdevice.
> 
> This patch adds a segment member to struct device_domain_info and uses
> the sub-device's BDF so that these sub-devices won't alias to other
> devices.
> 
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>

Acked-by: Lu Baolu <baolu.lu@linux.intel.com>

Best regards,
baolu

> ---
>   drivers/iommu/intel-iommu.c | 19 +++++++++++++++----
>   include/linux/intel-iommu.h |  1 +
>   2 files changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 1ff45b2..6d39b9b 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -2463,7 +2463,7 @@ static void do_deferred_attach(struct device *dev)
>   	struct device_domain_info *info;
>   
>   	list_for_each_entry(info, &device_domain_list, global)
> -		if (info->iommu->segment == segment && info->bus == bus &&
> +		if (info->segment == segment && info->bus == bus &&
>   		    info->devfn == devfn)
>   			return info;
>   
> @@ -2520,8 +2520,18 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
>   	if (!info)
>   		return NULL;
>   
> -	info->bus = bus;
> -	info->devfn = devfn;
> +	if (!dev_is_real_dma_subdevice(dev)) {
> +		info->bus = bus;
> +		info->devfn = devfn;
> +		info->segment = iommu->segment;
> +	} else {
> +		struct pci_dev *pdev = to_pci_dev(dev);
> +
> +		info->bus = pdev->bus->number;
> +		info->devfn = pdev->devfn;
> +		info->segment = pci_domain_nr(pdev->bus);
> +	}
> +
>   	info->ats_supported = info->pasid_supported = info->pri_supported = 0;
>   	info->ats_enabled = info->pasid_enabled = info->pri_enabled = 0;
>   	info->ats_qdep = 0;
> @@ -2561,7 +2571,8 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
>   
>   	if (!found) {
>   		struct device_domain_info *info2;
> -		info2 = dmar_search_domain_by_dev_info(iommu->segment, bus, devfn);
> +		info2 = dmar_search_domain_by_dev_info(info->segment, info->bus,
> +						       info->devfn);
>   		if (info2) {
>   			found      = info2->domain;
>   			info2->dev = dev;
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index 21633ce..4100bd2 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -609,6 +609,7 @@ struct device_domain_info {
>   	struct list_head auxiliary_domains; /* auxiliary domains
>   					     * attached to this device
>   					     */
> +	u32 segment;		/* PCI segment number */
>   	u8 bus;			/* PCI bus number */
>   	u8 devfn;		/* PCI devfn number */
>   	u16 pfsid;		/* SRIOV physical function source ID */
>