linux-kernel - Re: [PATCH 2/3] PCI/AER: Decode Requester ID when no error info found

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Message-ID: <6cc6adf0-e82d-4429-9e76-5fef7dda2d95@linux.intel.com>
Date: Tue, 2 Jan 2024 11:22:53 -0800
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
To: Bjorn Helgaas <helgaas@...nel.org>, linux-pci@...r.kernel.org
Cc: Mahesh J Salgaonkar <mahesh@...ux.ibm.com>,
 Oliver O'Halloran <oohall@...il.com>, Robert Richter <rrichter@....com>,
 Terry Bowman <terry.bowman@....com>,
 Kai-Heng Feng <kai.heng.feng@...onical.com>, linuxppc-dev@...ts.ozlabs.org,
 linux-kernel@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH 2/3] PCI/AER: Decode Requester ID when no error info found



On 12/6/2023 2:42 PM, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@...gle.com>
> 
> When a device with AER detects an error, it logs error information in its
> own AER Error Status registers.  It may send an Error Message to the Root
> Port (RCEC in the case of an RCiEP), which logs the fact that an Error
> Message was received (Root Error Status) and the Requester ID of the
> message source (Error Source Identification).
> 
> aer_print_port_info() prints the Requester ID from the Root Port Error
> Source in the usual Linux "bb:dd.f" format, but when find_source_device()
> finds no error details in the hierarchy below the Root Port, it printed the
> raw Requester ID without decoding it.
> 
> Decode the Requester ID in the usual Linux format so it matches other
> messages.
> 
> Sample message changes:
> 
>   - pcieport 0000:00:1c.5: AER: Correctable error received: 0000:00:1c.5
>   - pcieport 0000:00:1c.5: AER: can't find device of ID00e5
>   + pcieport 0000:00:1c.5: AER: Correctable error message received from 0000:00:1c.5
>   + pcieport 0000:00:1c.5: AER: found no error details for 0000:00:1c.5
> 
> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>

Except for the suggestion given below, it looks good to me.

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>

> ---
>  drivers/pci/pcie/aer.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 20db80018b5d..2ff6bac9979f 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -740,7 +740,7 @@ static void aer_print_port_info(struct pci_dev *dev, struct aer_err_info *info)
>  	u8 bus = info->id >> 8;
>  	u8 devfn = info->id & 0xff;
>  
> -	pci_info(dev, "%s%s error received: %04x:%02x:%02x.%d\n",
> +	pci_info(dev, "%s%s error message received from %04x:%02x:%02x.%d\n",
>  		 info->multi_error_valid ? "Multiple " : "",
>  		 aer_error_severity_string[info->severity],
>  		 pci_domain_nr(dev->bus), bus, PCI_SLOT(devfn),
> @@ -929,7 +929,12 @@ static bool find_source_device(struct pci_dev *parent,
>  		pci_walk_bus(parent->subordinate, find_device_iter, e_info);
>  
>  	if (!e_info->error_dev_num) {
> -		pci_info(parent, "can't find device of ID%04x\n", e_info->id);
> +		u8 bus = e_info->id >> 8;
> +		u8 devfn = e_info->id & 0xff;

You can use PCI_BUS_NUM(e_info->id) for getting bus number. Since you are
extracting this info in more than one place, maybe you can also define a
macro PCI_DEVFN(id) (following PCI_BUS_NUM()).

> +
> +		pci_info(parent, "found no error details for %04x:%02x:%02x.%d\n",
> +			 pci_domain_nr(parent->bus), bus, PCI_SLOT(devfn),
> +			 PCI_FUNC(devfn));
>  		return false;
>  	}
>  	return true;

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer