Messages in this thread | | | Date | Fri, 13 Jan 2023 16:49:21 +0800 | Subject | Re: [PATCH v2 1/1] PCI: Add translated request only flag for pci_enable_pasid() | From | Baolu Lu <> |
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On 2023/1/13 16:15, Matt Fagnani wrote: > Baolu, > > 6.2-rc3 with v2 of this patch applied booted normally without the black > screen problem. regzbot by Thorsten Leemhuis recommends adding the > following link tag to the previous discussion at > https://linux-regtracking.leemhuis.info/regzbot/mainline/ "When fixing, > add this to the commit message to make regzbot notice patch postings and > commits to resolve the issue:" Link: > https://lore.kernel.org/r/15d0f9ff-2a56-b3e9-5b45-e6b23300ae3b@leemhuis.info/
Sure. I will add below:
Fixes: 201007ef707a ("PCI: Enable PASID only when ACS RR & UF enabled on upstream path") Reported-by: Matt Fagnani <matt.fagnani@bell.net> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216865 Link: https://lore.kernel.org/r/15d0f9ff-2a56-b3e9-5b45-e6b23300ae3b@leemhuis.info/
By the way, can I add your tested-by?
-- Best regards, baolu
> > Thanks, > > Matt > > On 1/12/23 20:44, Lu Baolu wrote: >> The PCIe fabric routes Memory Requests based on the TLP address, ignoring >> the PASID. In order to ensure system integrity, commit 201007ef707a >> ("PCI: >> Enable PASID only when ACS RR & UF enabled on upstream path") requires >> some ACS features being supported on device's upstream path when enabling >> PCI/PASID. >> >> One alternative is ATS which lets the device resolve the PASID+addr pair >> before a memory request is made into a routeable TLB address through the >> TA. Those resolved addresses are then cached on the device instead of >> in the IOMMU TLB and the device always sets the translated bit for PASID. >> One example of those devices are AMD graphic devices that always have ACS >> or ATS enabled together with PASID. >> >> This adds a flag parameter in the pci_enable_pasid() helper, with which >> the device driver could opt-in the fact that device always sets the >> translated bit for PASID. >> >> It also applies this opt-in for AMD graphic devices. Without this change, >> kernel boots to black screen on a system with below AMD graphic device: >> >> 00:01.0 VGA compatible controller: Advanced Micro Devices, Inc. >> [AMD/ATI] Wani [Radeon R5/R6/R7 Graphics] (rev ca) >> (prog-if 00 [VGA controller]) >> DeviceName: ATI EG BROADWAY >> Subsystem: Hewlett-Packard Company Device 8332 >> >> At present, it is a common practice to enable/disable PCI PASID in the >> iommu drivers. Considering that the device driver knows more about the >> specific device, we will follow up by moving pci_enable_pasid() into >> the specific device drivers. >> >> Fixes: 201007ef707a ("PCI: Enable PASID only when ACS RR & UF enabled >> on upstream path") >> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216865 >> Reported-by: Matt Fagnani <matt.fagnani@bell.net> >> Suggested-by: Jason Gunthorpe <jgg@nvidia.com> >> Suggested-by: Christian König <christian.koenig@amd.com> >> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> >> --- >> include/linux/pci-ats.h | 6 ++++-- >> drivers/iommu/amd/iommu.c | 2 +- >> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 2 +- >> drivers/iommu/intel/iommu.c | 3 ++- >> drivers/pci/ats.c | 8 ++++++-- >> 5 files changed, 14 insertions(+), 7 deletions(-) >> >> Change log: >> v2: >> - Convert the bool to a named flag; >> - Convert TRANSLED to XLATED. >> >> v1: >> - >> https://lore.kernel.org/linux-iommu/20230112084629.737653-1-baolu.lu@linux.intel.com/ >> >> diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h >> index df54cd5b15db..750fca736ef4 100644 >> --- a/include/linux/pci-ats.h >> +++ b/include/linux/pci-ats.h >> @@ -4,6 +4,8 @@ >> #include <linux/pci.h> >> +#define PCI_PASID_XLATED_REQ_ONLY BIT(0) >> + >> #ifdef CONFIG_PCI_ATS >> /* Address Translation Service */ >> bool pci_ats_supported(struct pci_dev *dev); >> @@ -35,12 +37,12 @@ static inline bool pci_pri_supported(struct >> pci_dev *pdev) >> #endif /* CONFIG_PCI_PRI */ >> #ifdef CONFIG_PCI_PASID >> -int pci_enable_pasid(struct pci_dev *pdev, int features); >> +int pci_enable_pasid(struct pci_dev *pdev, int features, int flags); >> void pci_disable_pasid(struct pci_dev *pdev); >> int pci_pasid_features(struct pci_dev *pdev); >> int pci_max_pasids(struct pci_dev *pdev); >> #else /* CONFIG_PCI_PASID */ >> -static inline int pci_enable_pasid(struct pci_dev *pdev, int features) >> +static inline int pci_enable_pasid(struct pci_dev *pdev, int >> features, int flags) >> { return -EINVAL; } >> static inline void pci_disable_pasid(struct pci_dev *pdev) { } >> static inline int pci_pasid_features(struct pci_dev *pdev) >> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c >> index cbeaab55c0db..64a8c03d7dfa 100644 >> --- a/drivers/iommu/amd/iommu.c >> +++ b/drivers/iommu/amd/iommu.c >> @@ -1700,7 +1700,7 @@ static int pdev_pri_ats_enable(struct pci_dev >> *pdev) >> int ret; >> /* Only allow access to user-accessible pages */ >> - ret = pci_enable_pasid(pdev, 0); >> + ret = pci_enable_pasid(pdev, 0, PCI_PASID_XLATED_REQ_ONLY); >> if (ret) >> goto out_err; >> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> index ab160198edd6..891bf53c45dc 100644 >> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c >> @@ -2350,7 +2350,7 @@ static int arm_smmu_enable_pasid(struct >> arm_smmu_master *master) >> if (num_pasids <= 0) >> return num_pasids; >> - ret = pci_enable_pasid(pdev, features); >> + ret = pci_enable_pasid(pdev, features, 0); >> if (ret) { >> dev_err(&pdev->dev, "Failed to enable PASID\n"); >> return ret; >> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c >> index 59df7e42fd53..5cc13f02a5ac 100644 >> --- a/drivers/iommu/intel/iommu.c >> +++ b/drivers/iommu/intel/iommu.c >> @@ -1425,7 +1425,8 @@ static void iommu_enable_pci_caps(struct >> device_domain_info *info) >> undefined. So always enable PASID support on devices which >> have it, even if we can't yet know if we're ever going to >> use it. */ >> - if (info->pasid_supported && !pci_enable_pasid(pdev, >> info->pasid_supported & ~1)) >> + if (info->pasid_supported && >> + !pci_enable_pasid(pdev, info->pasid_supported & ~1, 0)) >> info->pasid_enabled = 1; >> if (info->pri_supported && >> diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c >> index f9cc2e10b676..3a2d9e0ba1d8 100644 >> --- a/drivers/pci/ats.c >> +++ b/drivers/pci/ats.c >> @@ -353,12 +353,15 @@ void pci_pasid_init(struct pci_dev *pdev) >> * pci_enable_pasid - Enable the PASID capability >> * @pdev: PCI device structure >> * @features: Features to enable >> + * @flags: device-specific flags >> + * - PCI_PASID_XLATED_REQ_ONLY: The PCI device only issues PASID >> + * memory requests of translated type. >> * >> * Returns 0 on success, negative value on error. This function checks >> * whether the features are actually supported by the device and >> returns >> * an error if not. >> */ >> -int pci_enable_pasid(struct pci_dev *pdev, int features) >> +int pci_enable_pasid(struct pci_dev *pdev, int features, int flags) >> { >> u16 control, supported; >> int pasid = pdev->pasid_cap; >> @@ -382,7 +385,8 @@ int pci_enable_pasid(struct pci_dev *pdev, int >> features) >> if (!pasid) >> return -EINVAL; >> - if (!pci_acs_path_enabled(pdev, NULL, PCI_ACS_RR | PCI_ACS_UF)) >> + if (!(flags & PCI_PASID_XLATED_REQ_ONLY) && >> + !pci_acs_path_enabled(pdev, NULL, PCI_ACS_RR | PCI_ACS_UF)) >> return -EINVAL; >> pci_read_config_word(pdev, pasid + PCI_PASID_CAP, &supported);
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