Re: [PATCH v5 07/23] iommu/vt-d: fix dev iotlb pfsid use

Lu Baolu
2018-05-14T01:52:04Z

Hi,

On 05/12/2018 04:53 AM, Jacob Pan wrote:
> PFSID should be used in the invalidation descriptor for flushing
> device IOTLBs on SRIOV VFs.

This patch could be submitted separately.

>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> ---
> drivers/iommu/dmar.c | 6 +++---
> drivers/iommu/intel-iommu.c | 16 +++++++++++++++-
> include/linux/intel-iommu.h | 5 ++---
> 3 files changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
> index 460bed4..7852678 100644
> --- a/drivers/iommu/dmar.c
> +++ b/drivers/iommu/dmar.c
> @@ -1339,8 +1339,8 @@ void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
> qi_submit_sync(&desc, iommu);
> }
>
> -void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 qdep,
> - u64 addr, unsigned mask)
> +void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
> + u16 qdep, u64 addr, unsigned mask)
> {
> struct qi_desc desc;
>
> @@ -1355,7 +1355,7 @@ void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 qdep,
> qdep = 0;
>
> desc.low = QI_DEV_IOTLB_SID(sid) | QI_DEV_IOTLB_QDEP(qdep) |
> - QI_DIOTLB_TYPE;
> + QI_DIOTLB_TYPE | QI_DEV_IOTLB_PFSID(pfsid);
>
> qi_submit_sync(&desc, iommu);
> }
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 4623294..732a10f 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -1459,6 +1459,19 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info)
> return;
>
> pdev = to_pci_dev(info->dev);
> + /* For IOMMU that supports device IOTLB throttling (DIT), we assign
> + * PFSID to the invalidation desc of a VF such that IOMMU HW can gauge
> + * queue depth at PF level. If DIT is not set, PFSID will be treated as
> + * reserved, which should be set to 0.
> + */
> + if (!ecap_dit(info->iommu->ecap))
> + info->pfsid = 0;
> + else if (pdev && pdev->is_virtfn) {
> + if (ecap_dit(info->iommu->ecap))
> + dev_warn(&pdev->dev, "SRIOV VF device IOTLB enabled without flow control\n");

I can't understand these two lines.

Isn't the condition always true? What does the error message mean?

> + info->pfsid = PCI_DEVID(pdev->physfn->bus->number, pdev->physfn->devfn);
> + } else
> + info->pfsid = PCI_DEVID(info->bus, info->devfn);
>
> #ifdef CONFIG_INTEL_IOMMU_SVM
> /* The PCIe spec, in its wisdom, declares that the behaviour of
> @@ -1524,7 +1537,8 @@ static void iommu_flush_dev_iotlb(struct dmar_domain *domain,
>
> sid = info->bus << 8 | info->devfn;
> qdep = info->ats_qdep;
> - qi_flush_dev_iotlb(info->iommu, sid, qdep, addr, mask);
> + qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
> + qdep, addr, mask);

Alignment should match open parenthesis.

> }
> spin_unlock_irqrestore(&device_domain_lock, flags);
> }
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index dfacd49..678a0f4 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -504,9 +504,8 @@ extern void qi_flush_context(struct intel_iommu *iommu, u16 did, u16 sid,
> u8 fm, u64 type);
> extern void qi_flush_iotlb(struct intel_iommu *iommu, u16 did, u64 addr,
> unsigned int size_order, u64 type);
> -extern void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 qdep,
> - u64 addr, unsigned mask);
> -
> +extern void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
> + u16 qdep, u64 addr, unsigned mask);

Alignment should match open parenthesis.

> extern int qi_submit_sync(struct qi_desc *desc, struct intel_iommu *iommu);
>
> extern int dmar_ir_support(void);

Best regards,
Lu Baolu