On Tue, Jun 06, 2017 at 03:01:36PM +0000, Shameerali Kolothum Thodi wrote: > Hi Lorenzo, > > > -----Original Message----- > > From: Lorenzo Pieralisi [mailto:lorenzo.pieralisi@xxxxxxx] > > Sent: Tuesday, June 06, 2017 2:56 PM > > To: Shameerali Kolothum Thodi > > Cc: marc.zyngier@xxxxxxx; sudeep.holla@xxxxxxx; will.deacon@xxxxxxx; > > robin.murphy@xxxxxxx; hanjun.guo@xxxxxxxxxx; Gabriele Paoloni; John > > Garry; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-arm- > > kernel@xxxxxxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; devel@xxxxxxxxxx; > > Linuxarm; Wangzhou (B); Guohanjun (Hanjun Guo) > > Subject: Re: [RFCv2 2/2] iommu/arm-smmu-v3:Enable ACPI based HiSilicon > > erratum 161010801 > > > > On Wed, May 31, 2017 at 03:32:13PM +0100, 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. > > > > > > The HW ITS address region associated with the dev is retrieved using a > > > new helper function added in the IORT code. > > > > Remove or rephrase last paragraph, it reads as if you are adding an IORT > > helper function in this patch but you actually aren't. > > Thanks for going through this patch series. I will remove this in next version. > > > > Signed-off-by: shameer <shameerali.kolothum.thodi@xxxxxxxxxx> > > > --- > > > drivers/iommu/arm-smmu-v3.c | 49 > > > ++++++++++++++++++++++++++++++++++++++++++--- > > > 1 file changed, 46 insertions(+), 3 deletions(-) > > > > > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu- > > v3.c > > > index abe4b88..3767526 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; > > > @@ -1755,6 +1756,38 @@ static bool arm_smmu_sid_in_range(struct > > > arm_smmu_device *smmu, u32 sid) > > > > > > static struct iommu_ops arm_smmu_ops; > > > > > > +#ifdef CONFIG_ACPI > > > +static struct iommu_resv_region *arm_smmu_acpi_alloc_hw_msi(struct > > > +device *dev) { > > > + struct iommu_resv_region *region; > > > + struct irq_domain *irq_dom; > > > + int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO; > > > + u64 base; > > > > phys_addr_t > > Ok. > > > > + irq_dom = pci_msi_get_device_domain(to_pci_dev(dev)); > > > + if (irq_dom) { > > > + int ret; > > > + u32 rid; > > > + > > > + rid = pci_msi_domain_get_msi_rid(irq_dom, > > to_pci_dev(dev)); > > > + ret = iort_dev_find_its_base(dev, rid, 0, &base); > > > > Well, here we use ITS id 0 which is fine as long as code in IORT uses the same > > policy for getting the irq_domain (ie we want to reserve the ITS address > > space that is actually used by the device to send IRQs not a a different one) it > > is just a heads-up because I find this confusing. > > Ok. Just to make it clear, 0 is the index into the ITS identifier list. > I noted that iort_get_device_domain() uses index 0 while retrieving the ITS identifier. > May be use the same approach here as well? ie, remove the index from function call? > > I am not sure, how we can get the index info though theoretically It is possible for > the ITS group node having multiple ITSs. Yes, it would be ideal to avoid the look-up through the ITS index and just reuse the ITS node associated with the MSI domain because I do not want this quirk to force the ITS domain allocation policy (what I mean I do not want to be tied to index 0 if for any reason we change the allocation in IORT for normal ITS<->device mapping). I will have a further look to see if we can improve the code to this extent. > > > + if (!ret) { > > > + dev_info(dev, "SMMUv3:HW MSI resv addr > > 0x%pa\n", &base); > > > + region = iommu_alloc_resv_region(base, SZ_128K, > > > + prot, > > IOMMU_RESV_MSI); > > > + return region; > > > + } > > > + } > > > + > > > + return NULL; > > > +} > > > +#else > > > +static struct iommu_resv_region *arm_smmu_acpi_alloc_hw_msi(struct > > > +device *dev) { > > > + return NULL; > > > +} > > > +#endif > > > + > > > static int arm_smmu_add_device(struct device *dev) { > > > int i, ret; > > > @@ -1903,11 +1936,20 @@ static int arm_smmu_of_xlate(struct device > > > *dev, struct of_phandle_args *args) static void > > arm_smmu_get_resv_regions(struct device *dev, > > > struct list_head *head) > > > { > > > - struct iommu_resv_region *region; > > > + struct iommu_fwspec *fwspec = dev->iommu_fwspec; > > > + struct iommu_resv_region *region = NULL; > > > int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO; > > > + struct arm_smmu_device *smmu; > > > + > > > + smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode); > > > > > > - region = iommu_alloc_resv_region(MSI_IOVA_BASE, > > MSI_IOVA_LENGTH, > > > - prot, IOMMU_RESV_SW_MSI); > > > + if (smmu && (smmu->options & ARM_SMMU_OPT_RESV_HW_MSI) > > && > > > + dev_is_pci(dev)) > > > + region = arm_smmu_acpi_alloc_hw_msi(dev); > > > > Is it safe to carry on if arm_smmu_acpi_alloc_hw_msi() returns NULL here ? > > It is just that PCIe devices won't be functional on this platforms as the endpoint will > be configured with ITS IOVA address. May be I should add some dev_warn() here. Well yes and also I am not sure that if arm_smmu_acpi_alloc_hw_msi() fails you should allocate the SW_MSI region I am not sure I understand the logic, so you should add a warning and just return on failure right ? Lorenzo -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
