From e3156048346c28c695f5cf9db67a8cf88c90f947 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Fri, 8 Apr 2016 15:12:24 +0200 Subject: [PATCH 1/3] iommu/amd: Fix checking of pci dma aliases Commit 61289cb ('iommu/amd: Remove old alias handling code') removed the old alias handling code from the AMD IOMMU driver because this is now handled by the IOMMU core code. But this also removed the handling of PCI aliases, which is not handled by the core code. This caused issues with PCI devices that have hidden PCIe-to-PCI bridges that rewrite the request-id. Fix this bug by re-introducing some of the removed functions from commit 61289cbaf6c8 and add a alias field 'struct iommu_dev_data'. This field carrys the return value of the get_alias() function and uses that instead of the amd_iommu_alias_table[] array in the code. Fixes: 61289cbaf6c8 ('iommu/amd: Remove old alias handling code') Cc: stable@vger.kernel.org # v4.4+ Tested-by: Tomasz Golinski Signed-off-by: Joerg Roedel --- drivers/iommu/amd_iommu.c | 87 ++++++++++++++++++++++++++++++++++----- 1 file changed, 76 insertions(+), 11 deletions(-) diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 374c129219ef..5efadad4615b 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -92,6 +92,7 @@ struct iommu_dev_data { struct list_head dev_data_list; /* For global dev_data_list */ struct protection_domain *domain; /* Domain the device is bound to */ u16 devid; /* PCI Device ID */ + u16 alias; /* Alias Device ID */ bool iommu_v2; /* Device can make use of IOMMUv2 */ bool passthrough; /* Device is identity mapped */ struct { @@ -166,6 +167,13 @@ static struct protection_domain *to_pdomain(struct iommu_domain *dom) return container_of(dom, struct protection_domain, domain); } +static inline u16 get_device_id(struct device *dev) +{ + struct pci_dev *pdev = to_pci_dev(dev); + + return PCI_DEVID(pdev->bus->number, pdev->devfn); +} + static struct iommu_dev_data *alloc_dev_data(u16 devid) { struct iommu_dev_data *dev_data; @@ -203,6 +211,68 @@ out_unlock: return dev_data; } +static int __last_alias(struct pci_dev *pdev, u16 alias, void *data) +{ + *(u16 *)data = alias; + return 0; +} + +static u16 get_alias(struct device *dev) +{ + struct pci_dev *pdev = to_pci_dev(dev); + u16 devid, ivrs_alias, pci_alias; + + devid = get_device_id(dev); + ivrs_alias = amd_iommu_alias_table[devid]; + pci_for_each_dma_alias(pdev, __last_alias, &pci_alias); + + if (ivrs_alias == pci_alias) + return ivrs_alias; + + /* + * DMA alias showdown + * + * The IVRS is fairly reliable in telling us about aliases, but it + * can't know about every screwy device. If we don't have an IVRS + * reported alias, use the PCI reported alias. In that case we may + * still need to initialize the rlookup and dev_table entries if the + * alias is to a non-existent device. + */ + if (ivrs_alias == devid) { + if (!amd_iommu_rlookup_table[pci_alias]) { + amd_iommu_rlookup_table[pci_alias] = + amd_iommu_rlookup_table[devid]; + memcpy(amd_iommu_dev_table[pci_alias].data, + amd_iommu_dev_table[devid].data, + sizeof(amd_iommu_dev_table[pci_alias].data)); + } + + return pci_alias; + } + + pr_info("AMD-Vi: Using IVRS reported alias %02x:%02x.%d " + "for device %s[%04x:%04x], kernel reported alias " + "%02x:%02x.%d\n", PCI_BUS_NUM(ivrs_alias), PCI_SLOT(ivrs_alias), + PCI_FUNC(ivrs_alias), dev_name(dev), pdev->vendor, pdev->device, + PCI_BUS_NUM(pci_alias), PCI_SLOT(pci_alias), + PCI_FUNC(pci_alias)); + + /* + * If we don't have a PCI DMA alias and the IVRS alias is on the same + * bus, then the IVRS table may know about a quirk that we don't. + */ + if (pci_alias == devid && + PCI_BUS_NUM(ivrs_alias) == pdev->bus->number) { + pdev->dev_flags |= PCI_DEV_FLAGS_DMA_ALIAS_DEVFN; + pdev->dma_alias_devfn = ivrs_alias & 0xff; + pr_info("AMD-Vi: Added PCI DMA alias %02x.%d for %s\n", + PCI_SLOT(ivrs_alias), PCI_FUNC(ivrs_alias), + dev_name(dev)); + } + + return ivrs_alias; +} + static struct iommu_dev_data *find_dev_data(u16 devid) { struct iommu_dev_data *dev_data; @@ -215,13 +285,6 @@ static struct iommu_dev_data *find_dev_data(u16 devid) return dev_data; } -static inline u16 get_device_id(struct device *dev) -{ - struct pci_dev *pdev = to_pci_dev(dev); - - return PCI_DEVID(pdev->bus->number, pdev->devfn); -} - static struct iommu_dev_data *get_dev_data(struct device *dev) { return dev->archdata.iommu; @@ -349,6 +412,8 @@ static int iommu_init_device(struct device *dev) if (!dev_data) return -ENOMEM; + dev_data->alias = get_alias(dev); + if (pci_iommuv2_capable(pdev)) { struct amd_iommu *iommu; @@ -369,7 +434,7 @@ static void iommu_ignore_device(struct device *dev) u16 devid, alias; devid = get_device_id(dev); - alias = amd_iommu_alias_table[devid]; + alias = get_alias(dev); memset(&amd_iommu_dev_table[devid], 0, sizeof(struct dev_table_entry)); memset(&amd_iommu_dev_table[alias], 0, sizeof(struct dev_table_entry)); @@ -1061,7 +1126,7 @@ static int device_flush_dte(struct iommu_dev_data *dev_data) int ret; iommu = amd_iommu_rlookup_table[dev_data->devid]; - alias = amd_iommu_alias_table[dev_data->devid]; + alias = dev_data->alias; ret = iommu_flush_dte(iommu, dev_data->devid); if (!ret && alias != dev_data->devid) @@ -2039,7 +2104,7 @@ static void do_attach(struct iommu_dev_data *dev_data, bool ats; iommu = amd_iommu_rlookup_table[dev_data->devid]; - alias = amd_iommu_alias_table[dev_data->devid]; + alias = dev_data->alias; ats = dev_data->ats.enabled; /* Update data structures */ @@ -2073,7 +2138,7 @@ static void do_detach(struct iommu_dev_data *dev_data) return; iommu = amd_iommu_rlookup_table[dev_data->devid]; - alias = amd_iommu_alias_table[dev_data->devid]; + alias = dev_data->alias; /* decrease reference counters */ dev_data->domain->dev_iommu[iommu->index] -= 1; From 5f634956cc550768ebd75cf26fdba01044bc600e Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 20 Apr 2016 14:53:32 +0100 Subject: [PATCH 2/3] iommu/arm-smmu: Fix stream-match conflict with IOMMU_DOMAIN_DMA Commit cbf8277ef456 ("iommu/arm-smmu: Treat IOMMU_DOMAIN_DMA as bypass for now") ignores requests to attach a device to the default domain since, without IOMMU-basked DMA ops available everywhere, the default domain will just lead to unexpected transaction faults being reported. Unfortunately, the way this was implemented on SMMUv2 causes a regression with VFIO PCI device passthrough under KVM on AMD Seattle. On this system, the host controller device is associated with both a pci_dev *and* a platform_device, and can therefore end up with duplicate SMR entries, resulting in a stream-match conflict at runtime. This patch amends the original fix so that attaching to IOMMU_DOMAIN_DMA is rejected even before configuring the SMRs. This restores the old behaviour for now, but we'll need to look at handing host controllers specially when we come to supporting the default domain fully. Reported-by: Eric Auger Tested-by: Eric Auger Tested-by: Yang Shi Signed-off-by: Will Deacon Signed-off-by: Joerg Roedel --- drivers/iommu/arm-smmu.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 2409e3bd3df2..5158febd889d 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -1089,18 +1089,20 @@ static int arm_smmu_domain_add_master(struct arm_smmu_domain *smmu_domain, struct arm_smmu_device *smmu = smmu_domain->smmu; void __iomem *gr0_base = ARM_SMMU_GR0(smmu); + /* + * FIXME: This won't be needed once we have IOMMU-backed DMA ops + * for all devices behind the SMMU. Note that we need to take + * care configuring SMRs for devices both a platform_device and + * and a PCI device (i.e. a PCI host controller) + */ + if (smmu_domain->domain.type == IOMMU_DOMAIN_DMA) + return 0; + /* Devices in an IOMMU group may already be configured */ ret = arm_smmu_master_configure_smrs(smmu, cfg); if (ret) return ret == -EEXIST ? 0 : ret; - /* - * FIXME: This won't be needed once we have IOMMU-backed DMA ops - * for all devices behind the SMMU. - */ - if (smmu_domain->domain.type == IOMMU_DOMAIN_DMA) - return 0; - for (i = 0; i < cfg->num_streamids; ++i) { u32 idx, s2cr; From 9800699c645952da6a7399194d3e762b84cde3cd Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Wed, 20 Apr 2016 14:53:33 +0100 Subject: [PATCH 3/3] iommu/arm-smmu: Don't allocate resources for bypass domains Until we get fully plumbed into of_iommu_configure, our default IOMMU_DOMAIN_DMA domains just bypass translation. Since we achieve that by leaving the stream table entries set to bypass instead of pointing at a translation context, the context bank we allocate for the domain is completely wasted. Context banks are typically a rather limited resource, so don't hog ones we don't need. Reported-by: Eric Auger Tested-by: Eric Auger Signed-off-by: Robin Murphy Signed-off-by: Will Deacon Signed-off-by: Joerg Roedel --- drivers/iommu/arm-smmu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 5158febd889d..7c39ac4b9c53 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -826,6 +826,12 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain, if (smmu_domain->smmu) goto out_unlock; + /* We're bypassing these SIDs, so don't allocate an actual context */ + if (domain->type == IOMMU_DOMAIN_DMA) { + smmu_domain->smmu = smmu; + goto out_unlock; + } + /* * Mapping the requested stage onto what we support is surprisingly * complicated, mainly because the spec allows S1+S2 SMMUs without @@ -948,7 +954,7 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) void __iomem *cb_base; int irq; - if (!smmu) + if (!smmu || domain->type == IOMMU_DOMAIN_DMA) return; /*