On 19/06/17 16:45, shameer wrote:
> The HiSilicon erratum 161010801 describes the limitation of HiSilicon
> platforms Hip06/Hip07 to support the SMMU mappings for MSI transactions.
>
> On these platforms GICv3 ITS translator is presented with the deviceID
> by extending the MSI payload data to 64 bits to include the deviceID.
> Hence, the PCIe controller on this platforms has to differentiate the
> MSI payload against other DMA payload and has to modify the MSI payload.
> This basically makes it difficult for this platforms to have a SMMU
> translation for MSI.
>
> This patch implements a ACPI table based quirk to reserve the hw msi
> regions in the smmu-v3 driver which means these address regions will
> not be translated and will be excluded from iova allocations.
>
> Signed-off-by: shameer <shameerali.kolothum.thodi@xxxxxxxxxx>
> ---
> drivers/iommu/arm-smmu-v3.c | 29 ++++++++++++++++++++++++-----
> 1 file changed, 24 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index abe4b88..f03c63b 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -597,6 +597,7 @@ struct arm_smmu_device {
> u32 features;
>
> #define ARM_SMMU_OPT_SKIP_PREFETCH (1 << 0)
> +#define ARM_SMMU_OPT_RESV_HW_MSI (1 << 1)
> u32 options;
>
> struct arm_smmu_cmdq cmdq;
> @@ -1904,14 +1905,31 @@ static void arm_smmu_get_resv_regions(struct device *dev,
> struct list_head *head)
> {
> struct iommu_resv_region *region;
> + struct arm_smmu_device *smmu;
> + struct iommu_fwspec *fwspec = dev->iommu_fwspec;
> int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
>
> - region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
> - prot, IOMMU_RESV_SW_MSI);
> - if (!region)
> - return;
> + smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
> +
> + if (smmu && (smmu->options & ARM_SMMU_OPT_RESV_HW_MSI) &&
AFAICS, iommu_get_resv_regions is only ever called on devices which are
at least already part of an iommu_group, so smmu should never
legitimately be NULL. I'd say if you really want to be robust against
flagrant API misuse, at least WARN_ON and bail out immediately.
Robin.
> + dev_is_pci(dev)) {
> + int ret = -EINVAL;
> +
> + if (!is_of_node(smmu->dev->fwnode))
> + ret = iort_iommu_its_get_resv_regions(dev, head);
>
> - list_add_tail(®ion->list, head);
> + if (ret) {
> + dev_warn(dev, "HW MSI region resv failed: %d\n", ret);
> + return;
> + }
> + } else {
> + region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
> + prot, IOMMU_RESV_SW_MSI);
> + if (!region)
> + return;
> +
> + list_add_tail(®ion->list, head);
> + }
>
> iommu_dma_get_resv_regions(dev, head);
> }
> @@ -2611,6 +2629,7 @@ static void parse_driver_acpi_options(struct acpi_iort_smmu_v3 *iort_smmu,
> switch (iort_smmu->model) {
> case ACPI_IORT_SMMU_HISILICON_HI161X:
> smmu->options |= ARM_SMMU_OPT_SKIP_PREFETCH;
> + smmu->options |= ARM_SMMU_OPT_RESV_HW_MSI;
> break;
> default:
> break;
>
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