RE: [PATCH v3 1/3] PCI/AER: Store UNCOR_STATUS bits that might be ANFE in aer_err_info
>-Original Message-
>From: Jonathan Cameron
>Subject: Re: [PATCH v3 1/3] PCI/AER: Store UNCOR_STATUS bits that might
>be ANFE in aer_err_info
>
>On Wed, 17 Apr 2024 14:14:05 +0800
>Zhenzhong Duan wrote:
>
>> In some cases the detector of a Non-Fatal Error(NFE) is not the most
>> appropriate agent to determine the type of the error. For example,
>> when software performs a configuration read from a non-existent
>> device or Function, completer will send an ERR_NONFATAL Message.
>> On some platforms, ERR_NONFATAL results in a System Error, which
>> breaks normal software probing.
>>
>> Advisory Non-Fatal Error(ANFE) is a special case that can be used
>> in above scenario. It is predominantly determined by the role of the
>> detecting agent (Requester, Completer, or Receiver) and the specific
>> error. In such cases, an agent with AER signals the NFE (if enabled)
>> by sending an ERR_COR Message as an advisory to software, instead of
>> sending ERR_NONFATAL.
>>
>> When processing an ANFE, ideally both correctable error(CE) status and
>> uncorrectable error(UE) status should be cleared. However, there is no
>> way to fully identify the UE associated with ANFE. Even worse, a Fatal
>> Error(FE) or Non-Fatal Error(NFE) may set the same UE status bit as
>> ANFE. Treating an ANFE as NFE will reproduce above mentioned issue,
>> i.e., breaking softwore probing; treating NFE as ANFE will make us
>> ignoring some UEs which need active recover operation. To avoid clearing
>> UEs that are not ANFE by accident, the most conservative route is taken
>> here: If any of the FE/NFE Detected bits is set in Device Status, do not
>> touch UE status, they should be cleared later by the UE handler. Otherwise,
>> a specific set of UEs that may be raised as ANFE according to the PCIe
>> specification will be cleared if their corresponding severity is Non-Fatal.
>>
>> To achieve above purpose, store UNCOR_STATUS bits that might be ANFE
>> in aer_err_info.anfe_status. So that those bits could be printed and
>> processed later.
>>
>> Tested-by: Yudong Wang
>> Co-developed-by: "Wang, Qingshun"
>> Signed-off-by: "Wang, Qingshun"
>> Signed-off-by: Zhenzhong Duan
>> ---
>> drivers/pci/pci.h | 1 +
>> drivers/pci/pcie/aer.c | 45
>++
>> 2 files changed, 46 insertions(+)
>>
>> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
>> index 17fed1846847..3f9eb807f9fd 100644
>> --- a/drivers/pci/pci.h
>> +++ b/drivers/pci/pci.h
>> @@ -412,6 +412,7 @@ struct aer_err_info {
>>
>> unsigned int status;/* COR/UNCOR Error Status */
>> unsigned int mask; /* COR/UNCOR Error Mask */
>> +unsigned int anfe_status; /* UNCOR Error Status for ANFE */
>> struct pcie_tlp_log tlp;/* TLP Header */
>> };
>>
>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> index ac6293c24976..27364ab4b148 100644
>> --- a/drivers/pci/pcie/aer.c
>> +++ b/drivers/pci/pcie/aer.c
>> @@ -107,6 +107,12 @@ struct aer_stats {
>> PCI_ERR_ROOT_MULTI_COR_RCV |
> \
>> PCI_ERR_ROOT_MULTI_UNCOR_RCV)
>>
>> +#define AER_ERR_ANFE_UNC_MASK
> (PCI_ERR_UNC_POISON_TLP | \
>> +PCI_ERR_UNC_COMP_TIME |
> \
>> +PCI_ERR_UNC_COMP_ABORT |
> \
>> +PCI_ERR_UNC_UNX_COMP |
> \
>> +PCI_ERR_UNC_UNSUP)
>> +
>> static int pcie_aer_disable;
>> static pci_ers_result_t aer_root_reset(struct pci_dev *dev);
>>
>> @@ -1196,6 +1202,41 @@ void aer_recover_queue(int domain, unsigned
>int bus, unsigned int devfn,
>> EXPORT_SYMBOL_GPL(aer_recover_queue);
>> #endif
>>
>> +static void anfe_get_uc_status(struct pci_dev *dev, struct aer_err_info
>*info)
>> +{
>> +u32 uncor_mask, uncor_status;
>> +u16 device_status;
>> +int aer = dev->aer_cap;
>> +
>> +if (pcie_capability_read_word(dev, PCI_EXP_DEVSTA,
>&device_status))
>> +return;
>> +/*
>> + * Take the most conservative route here. If there are
>> + * Non-Fatal/Fatal errors detected, do not assume any
>> + * bit in uncor_status is set by ANFE.
>> + */
>> +if (device_status & (PCI_EXP_DEVSTA_NFED | PCI_EXP_DEVSTA_FED))
>> +return;
>> +
>
>Is there not a race here? If we happen to get either an NFED or FED
>between the read of device_status above and here we might pick up a status
>that corresponds to that (and hence clear something we should not).
In this scenario, info->anfe_status is 0.
>
>Or am I missing that race being close somewhere?
The bits leading to NFED or FED is masked out when assigning info->anfe_status.
Bits for FED is masked out by ~info->severity,
bit for NFED is masked out by AER_ERR_ANFE_UNC_MASK.
So we never clear status bits for NFED or FED in ANFE handler.
See below assignment of info->anfe_status.
Than
RE: [PATCH v3 1/3] PCI/AER: Store UNCOR_STATUS bits that might be ANFE in aer_err_info
Hi Jonathan,
>-Original Message-
>From: Jonathan Cameron
>Subject: Re: [PATCH v3 1/3] PCI/AER: Store UNCOR_STATUS bits that might
>be ANFE in aer_err_info
>
>On Tue, 23 Apr 2024 02:25:05 +
>"Duan, Zhenzhong" wrote:
>
>> >-Original Message-
>> >From: Jonathan Cameron
>> >Subject: Re: [PATCH v3 1/3] PCI/AER: Store UNCOR_STATUS bits that
>might
>> >be ANFE in aer_err_info
>> >
>> >On Wed, 17 Apr 2024 14:14:05 +0800
>> >Zhenzhong Duan wrote:
>> >
>> >> In some cases the detector of a Non-Fatal Error(NFE) is not the most
>> >> appropriate agent to determine the type of the error. For example,
>> >> when software performs a configuration read from a non-existent
>> >> device or Function, completer will send an ERR_NONFATAL Message.
>> >> On some platforms, ERR_NONFATAL results in a System Error, which
>> >> breaks normal software probing.
>> >>
>> >> Advisory Non-Fatal Error(ANFE) is a special case that can be used
>> >> in above scenario. It is predominantly determined by the role of the
>> >> detecting agent (Requester, Completer, or Receiver) and the specific
>> >> error. In such cases, an agent with AER signals the NFE (if enabled)
>> >> by sending an ERR_COR Message as an advisory to software, instead of
>> >> sending ERR_NONFATAL.
>> >>
>> >> When processing an ANFE, ideally both correctable error(CE) status and
>> >> uncorrectable error(UE) status should be cleared. However, there is no
>> >> way to fully identify the UE associated with ANFE. Even worse, a Fatal
>> >> Error(FE) or Non-Fatal Error(NFE) may set the same UE status bit as
>> >> ANFE. Treating an ANFE as NFE will reproduce above mentioned issue,
>> >> i.e., breaking softwore probing; treating NFE as ANFE will make us
>> >> ignoring some UEs which need active recover operation. To avoid
>clearing
>> >> UEs that are not ANFE by accident, the most conservative route is taken
>> >> here: If any of the FE/NFE Detected bits is set in Device Status, do not
>> >> touch UE status, they should be cleared later by the UE handler.
>Otherwise,
>> >> a specific set of UEs that may be raised as ANFE according to the PCIe
>> >> specification will be cleared if their corresponding severity is
>> >> Non-Fatal.
>> >>
>> >> To achieve above purpose, store UNCOR_STATUS bits that might be
>ANFE
>> >> in aer_err_info.anfe_status. So that those bits could be printed and
>> >> processed later.
>> >>
>> >> Tested-by: Yudong Wang
>> >> Co-developed-by: "Wang, Qingshun"
>> >> Signed-off-by: "Wang, Qingshun"
>> >> Signed-off-by: Zhenzhong Duan
>> >> ---
>> >> drivers/pci/pci.h | 1 +
>> >> drivers/pci/pcie/aer.c | 45
>> >++
>> >> 2 files changed, 46 insertions(+)
>> >>
>> >> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
>> >> index 17fed1846847..3f9eb807f9fd 100644
>> >> --- a/drivers/pci/pci.h
>> >> +++ b/drivers/pci/pci.h
>> >> @@ -412,6 +412,7 @@ struct aer_err_info {
>> >>
>> >> unsigned int status;/* COR/UNCOR Error Status */
>> >> unsigned int mask; /* COR/UNCOR Error Mask */
>> >> + unsigned int anfe_status; /* UNCOR Error Status for ANFE */
>> >> struct pcie_tlp_log tlp;/* TLP Header */
>> >> };
>> >>
>> >> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> >> index ac6293c24976..27364ab4b148 100644
>> >> --- a/drivers/pci/pcie/aer.c
>> >> +++ b/drivers/pci/pcie/aer.c
>> >> @@ -107,6 +107,12 @@ struct aer_stats {
>> >> PCI_ERR_ROOT_MULTI_COR_RCV |
>> >\
>> >> PCI_ERR_ROOT_MULTI_UNCOR_RCV)
>> >>
>> >> +#define AER_ERR_ANFE_UNC_MASK
>> >(PCI_ERR_UNC_POISON_TLP | \
>> >> + PCI_ERR_UNC_COMP_TIME |
>> >\
>> >> + PCI_ERR_UNC_COMP_ABORT |
>> >\
>> >> + PCI_ERR_UNC_UNX_COMP |
>> >\
>> >> + PCI_ERR_UNC_UNSUP)
>> >> +
>> >>
RE: [PATCH v3 1/3] PCI/AER: Store UNCOR_STATUS bits that might be ANFE in aer_err_info
>-Original Message-
>From: Jonathan Cameron
>Subject: Re: [PATCH v3 1/3] PCI/AER: Store UNCOR_STATUS bits that might
>be ANFE in aer_err_info
>
>On Sun, 28 Apr 2024 03:31:11 +
>"Duan, Zhenzhong" wrote:
>
>> Hi Jonathan,
>>
>> >-Original Message-
>> >From: Jonathan Cameron
>> >Subject: Re: [PATCH v3 1/3] PCI/AER: Store UNCOR_STATUS bits that
>might
>> >be ANFE in aer_err_info
>> >
>> >On Tue, 23 Apr 2024 02:25:05 +
>> >"Duan, Zhenzhong" wrote:
>> >
>> >> >-Original Message-
>> >> >From: Jonathan Cameron
>> >> >Subject: Re: [PATCH v3 1/3] PCI/AER: Store UNCOR_STATUS bits that
>> >might
>> >> >be ANFE in aer_err_info
>> >> >
>> >> >On Wed, 17 Apr 2024 14:14:05 +0800
>> >> >Zhenzhong Duan wrote:
>> >> >
>> >> >> In some cases the detector of a Non-Fatal Error(NFE) is not the most
>> >> >> appropriate agent to determine the type of the error. For example,
>> >> >> when software performs a configuration read from a non-existent
>> >> >> device or Function, completer will send an ERR_NONFATAL Message.
>> >> >> On some platforms, ERR_NONFATAL results in a System Error, which
>> >> >> breaks normal software probing.
>> >> >>
>> >> >> Advisory Non-Fatal Error(ANFE) is a special case that can be used
>> >> >> in above scenario. It is predominantly determined by the role of the
>> >> >> detecting agent (Requester, Completer, or Receiver) and the specific
>> >> >> error. In such cases, an agent with AER signals the NFE (if enabled)
>> >> >> by sending an ERR_COR Message as an advisory to software, instead
>of
>> >> >> sending ERR_NONFATAL.
>> >> >>
>> >> >> When processing an ANFE, ideally both correctable error(CE) status
>and
>> >> >> uncorrectable error(UE) status should be cleared. However, there is
>no
>> >> >> way to fully identify the UE associated with ANFE. Even worse, a
>Fatal
>> >> >> Error(FE) or Non-Fatal Error(NFE) may set the same UE status bit as
>> >> >> ANFE. Treating an ANFE as NFE will reproduce above mentioned
>issue,
>> >> >> i.e., breaking softwore probing; treating NFE as ANFE will make us
>> >> >> ignoring some UEs which need active recover operation. To avoid
>> >clearing
>> >> >> UEs that are not ANFE by accident, the most conservative route is
>taken
>> >> >> here: If any of the FE/NFE Detected bits is set in Device Status, do
>not
>> >> >> touch UE status, they should be cleared later by the UE handler.
>> >Otherwise,
>> >> >> a specific set of UEs that may be raised as ANFE according to the
>PCIe
>> >> >> specification will be cleared if their corresponding severity is Non-
>Fatal.
>> >> >>
>> >> >> To achieve above purpose, store UNCOR_STATUS bits that might be
>> >ANFE
>> >> >> in aer_err_info.anfe_status. So that those bits could be printed and
>> >> >> processed later.
>> >> >>
>> >> >> Tested-by: Yudong Wang
>> >> >> Co-developed-by: "Wang, Qingshun"
>
>> >> >> Signed-off-by: "Wang, Qingshun"
>> >> >> Signed-off-by: Zhenzhong Duan
>> >> >> ---
>> >> >> drivers/pci/pci.h | 1 +
>> >> >> drivers/pci/pcie/aer.c | 45
>> >> >++
>> >> >> 2 files changed, 46 insertions(+)
>> >> >>
>> >> >> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
>> >> >> index 17fed1846847..3f9eb807f9fd 100644
>> >> >> --- a/drivers/pci/pci.h
>> >> >> +++ b/drivers/pci/pci.h
>> >> >> @@ -412,6 +412,7 @@ struct aer_err_info {
>> >> >>
>> >> >>unsigned int status;/* COR/UNCOR Error Status
>*/
>> >> >>unsigned int mask; /* COR/UNCOR Error Mask */
>> >> >> + unsigned int anfe_status; /* UNCOR Error Status for
>ANFE */
>> >> >>struct pcie_tlp_log tlp;/* TLP Header */
>> >> >> };
>> >> >>
RE: [PATCH v4 0/3] PCI/AER: Handle Advisory Non-Fatal error
Hi, Kindly ping. Appreciate comments and suggestions so I could go ahead. Thanks Zhenzhong >-Original Message- >From: Duan, Zhenzhong >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 :b7:02.0 > PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) >device [8086:0db0] error status/mask=2000/ > [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 :b7:02.0 > PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) >device [8086:0db0] error status/mask=2000/ > [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.w...@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.d...@intel.com >v2: https://lore.kernel.org/linux-pci/20240125062802.50819-1- >qingshun.w...@linux.intel.com >v1: https://lore.kernel.org/linux-pci/20240111073227.31488-1- >qingshun.w...@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
RE: [PATCH v4 1/3] PCI/AER: Store UNCOR_STATUS bits that might be ANFE in aer_err_info
Hi
>-Original Message-
>From: Kuppuswamy Sathyanarayanan
>
>Subject: Re: [PATCH v4 1/3] PCI/AER: Store UNCOR_STATUS bits that might
>be ANFE in aer_err_info
>
>Hi,
>
>On 5/9/24 1:48 AM, Zhenzhong Duan wrote:
>> In some cases the detector of a Non-Fatal Error(NFE) is not the most
>> appropriate agent to determine the type of the error. For example,
>> when software performs a configuration read from a non-existent
>> device or Function, completer will send an ERR_NONFATAL Message.
>> On some platforms, ERR_NONFATAL results in a System Error, which
>> breaks normal software probing.
>>
>> Advisory Non-Fatal Error(ANFE) is a special case that can be used
>> in above scenario. It is predominantly determined by the role of the
>> detecting agent (Requester, Completer, or Receiver) and the specific
>> error. In such cases, an agent with AER signals the NFE (if enabled)
>> by sending an ERR_COR Message as an advisory to software, instead of
>> sending ERR_NONFATAL.
>>
>> When processing an ANFE, ideally both correctable error(CE) status and
>> uncorrectable error(UE) status should be cleared. However, there is no
>> way to fully identify the UE associated with ANFE. Even worse, Non-Fatal
>> Error(NFE) may set the same UE status bit as ANFE. Treating an ANFE as
>> NFE will reproduce above mentioned issue, i.e., breaking softwore probing;
>> treating NFE as ANFE will make us ignoring some UEs which need active
>> recover operation. To avoid clearing UEs that are not ANFE by accident,
>> the most conservative route is taken here: If any of the NFE Detected
>> bits is set in Device Status, do not touch UE status, they should be
>> cleared later by the UE handler. Otherwise, a specific set of UEs that
>> may be raised as ANFE according to the PCIe specification will be cleared
>> if their corresponding severity is Non-Fatal.
>>
>> To achieve above purpose, store UNCOR_STATUS bits that might be ANFE
>> in aer_err_info.anfe_status. So that those bits could be printed and
>> processed later.
>>
>> Tested-by: Yudong Wang
>> Co-developed-by: "Wang, Qingshun"
>> Signed-off-by: "Wang, Qingshun"
>> Signed-off-by: Zhenzhong Duan
>> ---
>> drivers/pci/pci.h | 1 +
>> drivers/pci/pcie/aer.c | 53
>++
>> 2 files changed, 54 insertions(+)
>>
>> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
>> index 17fed1846847..3f9eb807f9fd 100644
>> --- a/drivers/pci/pci.h
>> +++ b/drivers/pci/pci.h
>> @@ -412,6 +412,7 @@ struct aer_err_info {
>>
>> unsigned int status;/* COR/UNCOR Error Status */
>> unsigned int mask; /* COR/UNCOR Error Mask */
>> +unsigned int anfe_status; /* UNCOR Error Status for ANFE */
>> struct pcie_tlp_log tlp;/* TLP Header */
>> };
>>
>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> index ac6293c24976..f2839b51321a 100644
>> --- a/drivers/pci/pcie/aer.c
>> +++ b/drivers/pci/pcie/aer.c
>> @@ -107,6 +107,12 @@ struct aer_stats {
>> PCI_ERR_ROOT_MULTI_COR_RCV |
> \
>> PCI_ERR_ROOT_MULTI_UNCOR_RCV)
>>
>> +#define AER_ERR_ANFE_UNC_MASK
> (PCI_ERR_UNC_POISON_TLP | \
>> +PCI_ERR_UNC_COMP_TIME |
> \
>> +PCI_ERR_UNC_COMP_ABORT |
> \
>> +PCI_ERR_UNC_UNX_COMP |
> \
>> +PCI_ERR_UNC_UNSUP)
>> +
>> static int pcie_aer_disable;
>> static pci_ers_result_t aer_root_reset(struct pci_dev *dev);
>>
>> @@ -1196,6 +1202,49 @@ void aer_recover_queue(int domain, unsigned
>int bus, unsigned int devfn,
>> EXPORT_SYMBOL_GPL(aer_recover_queue);
>> #endif
>>
>> +static void anfe_get_uc_status(struct pci_dev *dev, struct aer_err_info
>*info)
>> +{
>> +u32 uncor_mask, uncor_status, anfe_status;
>> +u16 device_status;
>> +int aer = dev->aer_cap;
>> +
>> +pci_read_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS,
>&uncor_status);
>> +pci_read_config_dword(dev, aer + PCI_ERR_UNCOR_MASK,
>&uncor_mask);
>> +/*
>> + * According to PCIe Base Specification Revision 6.1,
>> + * Section 6.2.3.2.4, if an UNCOR error is raised as
>> + * Advisory Non-Fatal error, it will match the following
>> + * conditions:
>> + * a. The severity of the error is Non-Fatal.
>> + * b. The error is one of the following:
>> + * 1. Poisoned TLP (Section 6.2.3.2.4.3)
>> + * 2. Completion Timeout (Section 6.2.3.2.4.4)
>> + * 3. Completer Abort(Section 6.2.3.2.4.1)
>> + * 4. Unexpected Completion (Section 6.2.3.2.4.5)
>> + * 5. Unsupported Request(Section 6.2.3.2.4.1)
>> + */
>> +anfe_status = uncor_status & ~uncor_mask & ~info->severity &
>> + AER_ERR_ANFE_UNC_MASK;
>> +
>> +if (pcie_capability_read_w
RE: [PATCH v4 3/3] PCI/AER: Clear UNCOR_STATUS bits that might be ANFE
>-Original Message-
>From: Kuppuswamy, Sathyanarayanan
>Subject: Re: [PATCH v4 3/3] PCI/AER: Clear UNCOR_STATUS bits that might
>be ANFE
>
>
>On 5/9/24 1:48 AM, Zhenzhong Duan wrote:
>> When processing an ANFE, ideally both correctable error(CE) status and
>> uncorrectable error(UE) status should be cleared. However, there is no
>> way to fully identify the UE associated with ANFE. Even worse, Non-Fatal
>> Error(NFE) may set the same UE status bit as ANFE. Treating an ANFE as
>> NFE will bring some issues, i.e., breaking softwore probing; treating
>/s/softwore/software
Good catch, will fix. It's strange 'checkpatch --codespell' doesn't catch this.
>
>May be this is already discussed. But can you explain why treating
>AFNE as non-fatal error will bring probing issues?
Copied below from spec 6.1, 6.2.3.2.4, says it can results in a System Error.
In some cases the detector of a non-fatal error is not the most appropriate
agent to determine whether the error is
recoverable or not, or if it even needs any recovery action at all. For
example, if software attempts to perform a
configuration read from a non-existent device or Function, the resulting UR
Status in the Completion will signal the error
to software, and software does not need for the Completer in addition to signal
the error by sending an ERR_NONFATAL
Message. In fact, on some platforms, signaling the error with ERR_NONFATAL
results in a System Error, which breaks
normal software probing.
>> NFE as ANFE will make us ignoring some UEs which need active recover
>/s/ignoring/ignore
Will fix.
>> operation. To avoid clearing UEs that are not ANFE by accident, the
>> most conservative route is taken here: If any of the NFE Detected bits
>> is set in Device Status, do not touch UE status, they should be cleared
>> later by the UE handler. Otherwise, a specific set of UEs that may be
>> raised as ANFE according to the PCIe specification will be cleared if
>> their corresponding severity is Non-Fatal.
>>
>> For instance, previously when kernel receives an ANFE with Poisoned TLP
>> in OS native AER mode, only status of CE will be reported and cleared:
>>
>> AER: Correctable error message received from :b7:02.0
>> PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID)
>> device [8086:0db0] error status/mask=2000/
>> [13] NonFatalErr
>>
>> If the kernel receives a Malformed TLP after that, two UEs will be
>> reported, which is unexpected. 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
>>
>> Now, for the same scenario, both CE status and related UE status will be
>> reported and cleared after ANFE:
>>
>> AER: Correctable error message received from :b7:02.0
>> PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID)
>> device [8086:0db0] error status/mask=2000/
>> [13] NonFatalErr
>> Uncorrectable errors that may cause Advisory Non-Fatal:
>> [18] TLP
>>
>> Tested-by: Yudong Wang
>> Co-developed-by: "Wang, Qingshun"
>> Signed-off-by: "Wang, Qingshun"
>> Signed-off-by: Zhenzhong Duan
>> ---
>> drivers/pci/pcie/aer.c | 7 ++-
>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>> index ed435f09ac27..6a6a3a40569a 100644
>> --- a/drivers/pci/pcie/aer.c
>> +++ b/drivers/pci/pcie/aer.c
>> @@ -1115,9 +1115,14 @@ static void pci_aer_handle_error(struct
>pci_dev *dev, struct aer_err_info *info)
>> * Correctable error does not need software intervention.
>> * No need to go through error recovery process.
>> */
>> -if (aer)
>> +if (aer) {
>> pci_write_config_dword(dev, aer +
>PCI_ERR_COR_STATUS,
>> info->status);
>> +if (info->anfe_status)
>> +pci_write_config_dword(dev,
>> + aer +
>PCI_ERR_UNCOR_STATUS,
>> + info->anfe_status);
>> +}
>
>Why split the handling part and storing part into two patches? Why not
>merge
>this part of patch 1/3.
This is based on Bjorn's suggestion at
https://www.spinics.net/lists/linux-pci/msg149012.html,
clearing UNCOR_STATUS might be more important, deserve to raise out.
Thanks
Zhenzhong
RE: [PATCH v4 1/3] PCI/AER: Store UNCOR_STATUS bits that might be ANFE in aer_err_info
>-Original Message-
>From: Kuppuswamy Sathyanarayanan
>
>Subject: Re: [PATCH v4 1/3] PCI/AER: Store UNCOR_STATUS bits that might
>be ANFE in aer_err_info
>
>
>On 6/13/24 7:39 PM, Duan, Zhenzhong wrote:
>> Hi
>>
>>> -Original Message-
>>> From: Kuppuswamy Sathyanarayanan
>>>
>>> Subject: Re: [PATCH v4 1/3] PCI/AER: Store UNCOR_STATUS bits that
>might
>>> be ANFE in aer_err_info
>>>
>>> Hi,
>>>
>>> On 5/9/24 1:48 AM, Zhenzhong Duan wrote:
>>>> In some cases the detector of a Non-Fatal Error(NFE) is not the most
>>>> appropriate agent to determine the type of the error. For example,
>>>> when software performs a configuration read from a non-existent
>>>> device or Function, completer will send an ERR_NONFATAL Message.
>>>> On some platforms, ERR_NONFATAL results in a System Error, which
>>>> breaks normal software probing.
>>>>
>>>> Advisory Non-Fatal Error(ANFE) is a special case that can be used
>>>> in above scenario. It is predominantly determined by the role of the
>>>> detecting agent (Requester, Completer, or Receiver) and the specific
>>>> error. In such cases, an agent with AER signals the NFE (if enabled)
>>>> by sending an ERR_COR Message as an advisory to software, instead of
>>>> sending ERR_NONFATAL.
>>>>
>>>> When processing an ANFE, ideally both correctable error(CE) status and
>>>> uncorrectable error(UE) status should be cleared. However, there is no
>>>> way to fully identify the UE associated with ANFE. Even worse, Non-Fatal
>>>> Error(NFE) may set the same UE status bit as ANFE. Treating an ANFE as
>>>> NFE will reproduce above mentioned issue, i.e., breaking softwore
>probing;
>>>> treating NFE as ANFE will make us ignoring some UEs which need active
>>>> recover operation. To avoid clearing UEs that are not ANFE by accident,
>>>> the most conservative route is taken here: If any of the NFE Detected
>>>> bits is set in Device Status, do not touch UE status, they should be
>>>> cleared later by the UE handler. Otherwise, a specific set of UEs that
>>>> may be raised as ANFE according to the PCIe specification will be cleared
>>>> if their corresponding severity is Non-Fatal.
>>>>
>>>> To achieve above purpose, store UNCOR_STATUS bits that might be
>ANFE
>>>> in aer_err_info.anfe_status. So that those bits could be printed and
>>>> processed later.
>>>>
>>>> Tested-by: Yudong Wang
>>>> Co-developed-by: "Wang, Qingshun"
>>>> Signed-off-by: "Wang, Qingshun"
>>>> Signed-off-by: Zhenzhong Duan
>>>> ---
>>>> drivers/pci/pci.h | 1 +
>>>> drivers/pci/pcie/aer.c | 53
>>> ++
>>>> 2 files changed, 54 insertions(+)
>>>>
>>>> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
>>>> index 17fed1846847..3f9eb807f9fd 100644
>>>> --- a/drivers/pci/pci.h
>>>> +++ b/drivers/pci/pci.h
>>>> @@ -412,6 +412,7 @@ struct aer_err_info {
>>>>
>>>>unsigned int status;/* COR/UNCOR Error Status */
>>>>unsigned int mask; /* COR/UNCOR Error Mask */
>>>> + unsigned int anfe_status; /* UNCOR Error Status for ANFE */
>>>>struct pcie_tlp_log tlp;/* TLP Header */
>>>> };
>>>>
>>>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>>>> index ac6293c24976..f2839b51321a 100644
>>>> --- a/drivers/pci/pcie/aer.c
>>>> +++ b/drivers/pci/pcie/aer.c
>>>> @@ -107,6 +107,12 @@ struct aer_stats {
>>>>PCI_ERR_ROOT_MULTI_COR_RCV |
>>> \
>>>>PCI_ERR_ROOT_MULTI_UNCOR_RCV)
>>>>
>>>> +#define AER_ERR_ANFE_UNC_MASK
>>> (PCI_ERR_UNC_POISON_TLP | \
>>>> + PCI_ERR_UNC_COMP_TIME |
>>> \
>>>> + PCI_ERR_UNC_COMP_ABORT |
>>> \
>>>> + PCI_ERR_UNC_UNX_COMP |
>>> \
>>>> + PCI_ERR_UNC_UNSUP)
>>>> +
>>>> static int pcie_aer_disable;
>>>> static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
RE: [PATCH v4 3/3] PCI/AER: Clear UNCOR_STATUS bits that might be ANFE
>-Original Message- >From: Kuppuswamy Sathyanarayanan > >Subject: Re: [PATCH v4 3/3] PCI/AER: Clear UNCOR_STATUS bits that might >be ANFE > > >On 6/13/24 7:40 PM, Duan, Zhenzhong wrote: >> >>> -Original Message- >>> From: Kuppuswamy, Sathyanarayanan >>> Subject: Re: [PATCH v4 3/3] PCI/AER: Clear UNCOR_STATUS bits that >might >>> be ANFE >>> >>> >>> On 5/9/24 1:48 AM, Zhenzhong Duan wrote: >>>> When processing an ANFE, ideally both correctable error(CE) status and >>>> uncorrectable error(UE) status should be cleared. However, there is no >>>> way to fully identify the UE associated with ANFE. Even worse, Non-Fatal >>>> Error(NFE) may set the same UE status bit as ANFE. Treating an ANFE as >>>> NFE will bring some issues, i.e., breaking softwore probing; treating >>> /s/softwore/software >> Good catch, will fix. It's strange 'checkpatch --codespell' doesn't catch >> this. >> >>> May be this is already discussed. But can you explain why treating >>> AFNE as non-fatal error will bring probing issues? >> Copied below from spec 6.1, 6.2.3.2.4, says it can results in a System Error. >> >> In some cases the detector of a non-fatal error is not the most appropriate >agent to determine whether the error is >> recoverable or not, or if it even needs any recovery action at all. For >example, if software attempts to perform a >> configuration read from a non-existent device or Function, the resulting UR >Status in the Completion will signal the error >> to software, and software does not need for the Completer in addition to >signal the error by sending an ERR_NONFATAL >> Message. In fact, on some platforms, signaling the error with >ERR_NONFATAL results in a System Error, which breaks >> normal software probing. >> >>>> NFE as ANFE will make us ignoring some UEs which need active recover >>> /s/ignoring/ignore >> Will fix. >> >>>> operation. To avoid clearing UEs that are not ANFE by accident, the >>>> most conservative route is taken here: If any of the NFE Detected bits >>>> is set in Device Status, do not touch UE status, they should be cleared >>>> later by the UE handler. Otherwise, a specific set of UEs that may be >>>> raised as ANFE according to the PCIe specification will be cleared if >>>> their corresponding severity is Non-Fatal. >>>> >>>> For instance, previously when kernel receives an ANFE with Poisoned >TLP >>>> in OS native AER mode, only status of CE will be reported and cleared: >>>> >>>> AER: Correctable error message received from :b7:02.0 >>>> PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver >ID) >>>> device [8086:0db0] error status/mask=2000/ >>>> [13] NonFatalErr >>>> >>>> If the kernel receives a Malformed TLP after that, two UEs will be >>>> reported, which is unexpected. 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 >>>> >>>> Now, for the same scenario, both CE status and related UE status will be >>>> reported and cleared after ANFE: >>>> >>>> AER: Correctable error message received from :b7:02.0 >>>> PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver >ID) >>>> device [8086:0db0] error status/mask=2000/ >>>> [13] NonFatalErr >>>> Uncorrectable errors that may cause Advisory Non-Fatal: >>>> [18] TLP >>>> >>>> Tested-by: Yudong Wang >>>> Co-developed-by: "Wang, Qingshun" >>>> Signed-off-by: "Wang, Qingshun" >>>> Signed-off-by: Zhenzhong Duan >>>> --- >>>> drivers/pci/pcie/aer.c | 7 ++- >>>> 1 file changed, 6 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c >>>> index ed435f09ac27..6a6a3a40569a 100644 >>>> --- a/drivers/pci/pcie/aer.c >>>> +++ b/drivers/pci/pcie/aer.c >>>> @@ -1115,9 +1115,14 @@ static void pci_aer_handle_
RE: [PATCH v5 0/2] PCI/AER: Handle Advisory Non-Fatal error
Hi Bjorn, Kindly ping, this series got Reviewed-by and no comments for a month. Will you think about picking it or further improvements are needed. Look forward to your suggestions. Thanks Zhenzhong >-Original Message- >From: Duan, Zhenzhong >Subject: [PATCH v5 0/2] 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 :b7:02.0 > PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) >device [8086:0db0] error status/mask=2000/ > [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 :b7:02.0 > PCIe Bus Error: severity=Correctable, type=Transaction Layer, (Receiver ID) >device [8086:0db0] error status/mask=2000/ > [13] NonFatalErr >Uncorrectable errors that may cause Advisory Non-Fatal: > [12] TLP > >Note: >checkpatch.pl will produce following warnings on PATCH1&2: > >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.w...@linux.intel.com > >Thanks >Qingshun, Zhenzhong > >Changelog: >v5: > - squash patch 1 and 3 (Kuppuswamy) > - add comment about avoiding race and fix typo error (Kuppuswamy) > - collect Jonathan and Kuppuswamy's R-b > >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. > >v4: https://lkml.org/lkml/2024/5/9/247 >v3: https://lore.kernel.org/lkml/20240417061407.1491361-1- >zhenzhong.d...@intel.com >v2: https://lore.kernel.org/linux-pci/20240125062802.50819-1- >qingshun.w...@linux.intel.com >v1: https://lore.kernel.org/linux-pci/20240111073227.31488-1- >qingshun.w...@linux.intel.com > > >Zhenzhong Duan (2): > PCI/AER: Clear UNCOR_STATUS bits that might be ANFE > PCI/AER: Print UNCOR_STATUS bits that might be ANFE > > drivers/pci/pci.h | 1 + > drivers/pci/pcie/aer.c | 79 >+- > 2 files changed, 79 insertions(+), 1 deletion(-) > >-- >2.34.1
