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

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Message-ID: <20240102225327.GA1739520@bhelgaas>
Date: Tue, 2 Jan 2024 16:53:27 -0600
From: Bjorn Helgaas <helgaas@...nel.org>
To: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
Cc: linux-pci@...r.kernel.org, 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 Tue, Jan 02, 2024 at 11:22:53AM -0800, Kuppuswamy Sathyanarayanan wrote:
> 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>

Thanks for taking a look!

> > @@ -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()).

Thanks, both good ideas.

We already have a PCI_DEVFN() that *combines* slot + func into devfn,
so we'd have to come up with a different name.

I'll add a patch to use PCI_BUS_NUM() in the two places here and in
pme.c.

I think I'll wait with these until after the v6.7 release.

> > +		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