Re: [PATCH ats_vtd v5 20/22] pci: add a pci-level API for ATS

[Minwoo Im <minwoo.im@samsung.com>]

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On 24-07-02 05:52:45, CLEMENT MATHIEU--DRIF wrote:
> From: Clément Mathieu--Drif <clement.mathieu--drif@eviden.com>
> 
> Devices implementing ATS can send translation requests using
> pci_ats_request_translation_pasid.
> 
> The invalidation events are sent back to the device using the iommu
> notifier managed with pci_register_iommu_tlb_event_notifier and
> pci_unregister_iommu_tlb_event_notifier
> 
> Signed-off-by: Clément Mathieu--Drif <clement.mathieu--drif@eviden.com>
> ---
>  hw/pci/pci.c         | 44 +++++++++++++++++++++++++++++++++++++
>  include/hw/pci/pci.h | 52 ++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 96 insertions(+)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 7a483dd05d..93b816aff2 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -2833,6 +2833,50 @@ void pci_device_unset_iommu_device(PCIDevice *dev)
>      }
>  }
>  
> +ssize_t pci_ats_request_translation_pasid(PCIDevice *dev, uint32_t pasid,
> +                                          bool priv_req, bool exec_req,
> +                                          hwaddr addr, size_t length,
> +                                          bool no_write, IOMMUTLBEntry *result,
> +                                          size_t result_length,
> +                                          uint32_t *err_count)
> +{
> +    assert(result_length);
> +    IOMMUMemoryRegion *iommu_mr = pci_device_iommu_memory_region_pasid(dev,
> +                                                                        pasid);
> +    if (!iommu_mr || !pcie_ats_enabled(dev)) {
> +        return -EPERM;
> +    }
> +    return memory_region_iommu_ats_request_translation(iommu_mr, priv_req,
> +                                                       exec_req, addr, length,
> +                                                       no_write, result,
> +                                                       result_length,
> +                                                       err_count);
> +}

Can we use this function not from the endpoint PCI device, but inside of the pci
subsystem (hw/pci/pci.c) to make transparent abstraction for ATS request from
PCI endpoint device POV?  I guess it would be better to have PCI subsystem to
issue ATS request if pcie_ats_enabled(dev) rather than calling from the endpoint
side.

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