[RFC PATCH 18/30] PCI: Make "PRG Response PASID Required" handling common

Bjorn Helgaas
2017-03-03T21:11:40Z

On Mon, Feb 27, 2017 at 07:54:29PM +0000, Jean-Philippe Brucker wrote:
> The PASID ECN to the PCIe spec added a bit in the PRI status register that
> allows a Function to declare whether a PRG Response should contain the
> PASID prefix or not.
>
> Move the helper that accesses it from amd_iommu into the PCI subsystem,
> renaming it to something more consistent with the spec, and introducing
> another obscure acronym to make it all fit.

Maybe mention the acronym itelf and spell it out here?

> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
> drivers/iommu/amd_iommu.c | 19 +------------------
> drivers/pci/ats.c | 17 +++++++++++++++++
> include/linux/pci-ats.h | 8 ++++++++
> include/uapi/linux/pci_regs.h | 1 +
> 4 files changed, 27 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
> index 98940d1392cb..c5c598bf4ba3 100644
> --- a/drivers/iommu/amd_iommu.c
> +++ b/drivers/iommu/amd_iommu.c
> @@ -2024,23 +2024,6 @@ static int pdev_iommuv2_enable(struct pci_dev *pdev)
> return ret;
> }
>
> -/* FIXME: Move this to PCI code */
> -#define PCI_PRI_TLP_OFF (1 << 15)
> -
> -static bool pci_pri_tlp_required(struct pci_dev *pdev)
> -{
> - u16 status;
> - int pos;
> -
> - pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
> - if (!pos)
> - return false;
> -
> - pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
> -
> - return (status & PCI_PRI_TLP_OFF) ? true : false;
> -}
> -
> /*
> * If a device is not yet associated with a domain, this function
> * assigns it visible for the hardware
> @@ -2069,7 +2052,7 @@ static int attach_device(struct device *dev,
>
> dev_data->ats.enabled = true;
> dev_data->ats.qdep = pci_ats_queue_depth(pdev);
> - dev_data->pri_tlp = pci_pri_tlp_required(pdev);
> + dev_data->pri_tlp = pci_prg_resp_requires_prefix(pdev);
> }
> } else if (amd_iommu_iotlb_sup &&
> pci_enable_ats(pdev, PAGE_SHIFT) == 0) {
> diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
> index eeb9fb2b47aa..331376e9bb8b 100644
> --- a/drivers/pci/ats.c
> +++ b/drivers/pci/ats.c
> @@ -334,3 +334,20 @@ int pci_max_pasids(struct pci_dev *pdev)
> }
> EXPORT_SYMBOL_GPL(pci_max_pasids);
> #endif /* CONFIG_PCI_PASID */
> +
> +#if defined(CONFIG_PCI_PASID) && defined(CONFIG_PCI_PRI)
> +bool pci_prg_resp_requires_prefix(struct pci_dev *pdev)
> +{
> + u16 status;
> + int pos;
> +
> + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
> + if (!pos)
> + return false;
> +
> + pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
> +
> + return !!(status & PCI_PRI_STATUS_PRPR);
> +}
> +EXPORT_SYMBOL_GPL(pci_prg_resp_requires_prefix);
> +#endif /* CONFIG_PCI_PASID && CONFIG_PCI_PRI */
> diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h
> index 57e0b8250947..e21bcacbe80c 100644
> --- a/include/linux/pci-ats.h
> +++ b/include/linux/pci-ats.h
> @@ -57,5 +57,13 @@ static inline int pci_max_pasids(struct pci_dev *pdev)
>
> #endif /* CONFIG_PCI_PASID */
>
> +#if defined(CONFIG_PCI_PASID) && defined(CONFIG_PCI_PRI)
> +bool pci_prg_resp_requires_prefix(struct pci_dev *pdev);
> +#else
> +static inline bool pci_prg_resp_requires_prefix(struct pci_dev *pdev)
> +{
> + return false;
> +}
> +#endif /* CONFIG_PCI_PASID && CONFIG_PCI_PRI */
>
> #endif /* LINUX_PCI_ATS_H*/
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index 634c9c44ed6c..bae815876be6 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -864,6 +864,7 @@
> #define PCI_PRI_STATUS_RF 0x001 /* Response Failure */
> #define PCI_PRI_STATUS_UPRGI 0x002 /* Unexpected PRG index */
> #define PCI_PRI_STATUS_STOPPED 0x100 /* PRI Stopped */
> +#define PCI_PRI_STATUS_PRPR 0x8000 /* PRG Response requires PASID prefix */
> #define PCI_PRI_MAX_REQ 0x08 /* PRI max reqs supported */
> #define PCI_PRI_ALLOC_REQ 0x0c /* PRI max reqs allowed */
> #define PCI_EXT_CAP_PRI_SIZEOF 16
> --
> 2.11.0
>
>
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