| Message ID | 20240509084833.2147767-1-zhenzhong.duan@intel.com |
|---|---|
| Headers | show |
| Series | PCI/AER: Handle Advisory Non-Fatal error | expand |
Hi, Kindly ping. Appreciate comments and suggestions so I could go ahead. Thanks Zhenzhong >-----Original Message----- >From: Duan, Zhenzhong <zhenzhong.duan@intel.com> >Subject: [PATCH v4 0/3] PCI/AER: Handle Advisory Non-Fatal error > >Hi, > >This is a relay work of Qingshun's v2 [1], but changed to focus on ANFE >processing as subject suggests and drops trace-event for now. I think it's >a bit heavy to do extra IOes to get PCIe registers only for trace purpose >and not see it a community request for now. > >According to PCIe Base Specification Revision 6.1, Sections 6.2.3.2.4 and >6.2.4.3, certain uncorrectable errors will signal ERR_COR instead of >ERR_NONFATAL, logged as Advisory Non-Fatal Error(ANFE), and set bits in >both Correctable Error(CE) Status register and Uncorrectable Error(UE) >Status register. Currently, when handling AER events the kernel will only >look at CE status or UE status, but never both. In the ANFE case, bits set >in the UE status register will not be reported and cleared until the next >FE/NFE arrives. > >For instance, previously, when the kernel receives an ANFE with Poisoned >TLP in OS native AER mode, only the status of CE will be reported and >cleared: > > AER: Correctable error message received from 0000:b7:02.0 > PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) > device [8086:0db0] error status/mask=00002000/00000000 > [13] NonFatalErr > >If the kernel receives a Malformed TLP after that, two UEs will be >reported, which is unexpected. The Malformed TLP Header is lost since >the previous ANFE gated the TLP header logs: > > PCIe Bus Error: severity="Uncorrectable (Fatal), type=Transaction Layer, >(Receiver ID) > device [8086:0db0] error status/mask=00041000/00180020 > [12] TLP (First) > [18] MalfTLP > >To handle this case properly, calculate potential ANFE related status bits >and save in aer_err_info. Use this information to determine the status bits >that need to be cleared. > >Now, for the previous scenario, both CE status and related UE status will >be reported and cleared after ANFE: > > AER: Correctable error message received from 0000:b7:02.0 > PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) > device [8086:0db0] error status/mask=00002000/00000000 > [13] NonFatalErr > Uncorrectable errors that may cause Advisory Non-Fatal: > [18] TLP > >Note: >checkpatch.pl will produce following warnings on PATCH2/3: > >WARNING: 'UE' may be misspelled - perhaps 'USE'? >#22: >uncorrectable error(UE) status should be cleared. However, there is no > >...similar warnings omitted... > >This is a false-positive, so not fixed. > >WARNING: Prefer a maximum 75 chars per line (possible unwrapped commit >description?) >#10: > PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) > >...similar warnings omitted... > >For readability reasons, these warnings are not fixed. > > > >[1] https://lore.kernel.org/linux-pci/20240125062802.50819-1- >qingshun.wang@linux.intel.com > >Thanks >Qingshun, Zhenzhong > >Changelog: >v4: > - Fix a race in anfe_get_uc_status() (Jonathan) > - Add a comment to explain side effect of processing ANFE as NFE (Jonathan) > - Drop the check for PCI_EXP_DEVSTA_NFED > >v3: > - Split ANFE print and processing to two patches (Bjorn) > - Simplify ANFE handling, drop trace event > - Polish comments and patch description > - Add Tested-by > >v2: > - Reference to the latest PCIe Specification in both commit messages > and comments, as suggested by Bjorn Helgaas. > - Describe the reason for storing additional information in > aer_err_info in the commit message of PATCH 1, as suggested by Bjorn > Helgaas. > - Add more details of behavior changes in the commit message of PATCH > 2, as suggested by Bjorn Helgaas. > >v3: https://lore.kernel.org/lkml/20240417061407.1491361-1- >zhenzhong.duan@intel.com >v2: https://lore.kernel.org/linux-pci/20240125062802.50819-1- >qingshun.wang@linux.intel.com >v1: https://lore.kernel.org/linux-pci/20240111073227.31488-1- >qingshun.wang@linux.intel.com > >Zhenzhong Duan (3): > PCI/AER: Store UNCOR_STATUS bits that might be ANFE in aer_err_info > PCI/AER: Print UNCOR_STATUS bits that might be ANFE > PCI/AER: Clear UNCOR_STATUS bits that might be ANFE > > drivers/pci/pci.h | 1 + > drivers/pci/pcie/aer.c | 75 >+++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 75 insertions(+), 1 deletion(-) > >-- >2.34.1
Hi, This is a relay work of Qingshun's v2 [1], but changed to focus on ANFE processing as subject suggests and drops trace-event for now. I think it's a bit heavy to do extra IOes to get PCIe registers only for trace purpose and not see it a community request for now. According to PCIe Base Specification Revision 6.1, Sections 6.2.3.2.4 and 6.2.4.3, certain uncorrectable errors will signal ERR_COR instead of ERR_NONFATAL, logged as Advisory Non-Fatal Error(ANFE), and set bits in both Correctable Error(CE) Status register and Uncorrectable Error(UE) Status register. Currently, when handling AER events the kernel will only look at CE status or UE status, but never both. In the ANFE case, bits set in the UE status register will not be reported and cleared until the next FE/NFE arrives. For instance, previously, when the kernel receives an ANFE with Poisoned TLP in OS native AER mode, only the status of CE will be reported and cleared: AER: Correctable error message received from 0000:b7:02.0 PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) device [8086:0db0] error status/mask=00002000/00000000 [13] NonFatalErr If the kernel receives a Malformed TLP after that, two UEs will be reported, which is unexpected. The Malformed TLP Header is lost since the previous ANFE gated the TLP header logs: PCIe Bus Error: severity="Uncorrectable (Fatal), type=Transaction Layer, (Receiver ID) device [8086:0db0] error status/mask=00041000/00180020 [12] TLP (First) [18] MalfTLP To handle this case properly, calculate potential ANFE related status bits and save in aer_err_info. Use this information to determine the status bits that need to be cleared. Now, for the previous scenario, both CE status and related UE status will be reported and cleared after ANFE: AER: Correctable error message received from 0000:b7:02.0 PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) device [8086:0db0] error status/mask=00002000/00000000 [13] NonFatalErr Uncorrectable errors that may cause Advisory Non-Fatal: [18] TLP Note: checkpatch.pl will produce following warnings on PATCH2/3: WARNING: 'UE' may be misspelled - perhaps 'USE'? #22: uncorrectable error(UE) status should be cleared. However, there is no ...similar warnings omitted... This is a false-positive, so not fixed. WARNING: Prefer a maximum 75 chars per line (possible unwrapped commit description?) #10: PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) ...similar warnings omitted... For readability reasons, these warnings are not fixed. [1] https://lore.kernel.org/linux-pci/20240125062802.50819-1-qingshun.wang@linux.intel.com Thanks Qingshun, Zhenzhong Changelog: v4: - Fix a race in anfe_get_uc_status() (Jonathan) - Add a comment to explain side effect of processing ANFE as NFE (Jonathan) - Drop the check for PCI_EXP_DEVSTA_NFED v3: - Split ANFE print and processing to two patches (Bjorn) - Simplify ANFE handling, drop trace event - Polish comments and patch description - Add Tested-by v2: - Reference to the latest PCIe Specification in both commit messages and comments, as suggested by Bjorn Helgaas. - Describe the reason for storing additional information in aer_err_info in the commit message of PATCH 1, as suggested by Bjorn Helgaas. - Add more details of behavior changes in the commit message of PATCH 2, as suggested by Bjorn Helgaas. v3: https://lore.kernel.org/lkml/20240417061407.1491361-1-zhenzhong.duan@intel.com v2: https://lore.kernel.org/linux-pci/20240125062802.50819-1-qingshun.wang@linux.intel.com v1: https://lore.kernel.org/linux-pci/20240111073227.31488-1-qingshun.wang@linux.intel.com Zhenzhong Duan (3): PCI/AER: Store UNCOR_STATUS bits that might be ANFE in aer_err_info PCI/AER: Print UNCOR_STATUS bits that might be ANFE PCI/AER: Clear UNCOR_STATUS bits that might be ANFE drivers/pci/pci.h | 1 + drivers/pci/pcie/aer.c | 75 +++++++++++++++++++++++++++++++++++++++++- 2 files changed, 75 insertions(+), 1 deletion(-)