RE: [PATCH] platform/x86/intel/vsec: Restore BAR fallback for header walk

[Ruhl, Michael J]

>-----Original Message-----
>From: David Box <david.e.box@xxxxxxxxxxxxxxx>
>Sent: Sunday, June 7, 2026 3:39 PM
>To: Ruhl, Michael J <michael.j.ruhl@xxxxxxxxx>
>Cc: ilpo.jarvinen@xxxxxxxxxxxxxxx; Brost, Matthew
><matthew.brost@xxxxxxxxx>; thomas.hellstrom@xxxxxxxxxxxxxxx; intel-
>xe@xxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; platform-driver-
>x86@xxxxxxxxxxxxxxx
>Subject: Re: [PATCH] platform/x86/intel/vsec: Restore BAR fallback for header
>walk
>
>On Wed, Jun 03, 2026 at 06:32:32PM +0000, Ruhl, Michael J wrote:
>> >-----Original Message-----
>> >From: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
>> >Sent: Friday, May 29, 2026 2:32 PM
>> >To: ilpo.jarvinen@xxxxxxxxxxxxxxx; Ruhl, Michael J
><michael.j.ruhl@xxxxxxxxx>;
>> >david.e.box@xxxxxxxxxxxxxxx
>> >Cc: Brost, Matthew <matthew.brost@xxxxxxxxx>;
>> >thomas.hellstrom@xxxxxxxxxxxxxxx; intel-xe@xxxxxxxxxxxxxxxxxxxxx; linux-
>> >kernel@xxxxxxxxxxxxxxx; platform-driver-x86@xxxxxxxxxxxxxxx
>> >Subject: [PATCH] platform/x86/intel/vsec: Restore BAR fallback for header
>walk
>> >
>> >The base_addr refactor changed intel_vsec_walk_header() to pass
>> >info->base_addr as the discovery-table base address. For the PCI VSEC
>> >driver this info comes from driver_data, but exported callers may provide
>> >their own static headers and leave base_addr unset.
>> >
>> >For xe, this made the discovery-table base address zero instead of the BAR
>> >selected by header->tbir, preventing PMT endpoints from being created.
>> >
>> >Restore the previous behavior for the header-walk path by falling back to
>> >pci_resource_start(pdev, header->tbir) when base_addr is not specified.
>> >Keep explicit base_addr override behavior unchanged.
>> >
>> >This preserves the refactor structure while fixing the functional
>> >regression in manual-header users.
>> >
>> >Fixes: 904b333fc51c ("platform/x86/intel/vsec: Refactor base_addr
>handling")
>> >Assisted-by: Claude:claude-sonnet-4-6
>> >Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
>> >---
>> > drivers/platform/x86/intel/vsec.c | 17 ++++++++++++++++-
>> > 1 file changed, 16 insertions(+), 1 deletion(-)
>> >
>> >diff --git a/drivers/platform/x86/intel/vsec.c
>> >b/drivers/platform/x86/intel/vsec.c
>> >index 1657834fd275..3c6d8a1928c0 100644
>> >--- a/drivers/platform/x86/intel/vsec.c
>> >+++ b/drivers/platform/x86/intel/vsec.c
>> >@@ -482,10 +482,25 @@ static int intel_vsec_walk_header(struct device
>> >*dev,
>> > 				  const struct intel_vsec_platform_info *info)
>> > {
>> > 	struct intel_vsec_header **header = info->headers;
>> >+	u64 base_addr;
>> > 	int ret;
>> >
>> > 	for ( ; *header; header++) {
>> >-		ret = intel_vsec_register_device(dev, *header, info, info-
>>base_addr);
>> >+		if (info->base_addr) {
>> >+			base_addr = info->base_addr;
>> >+		} else {
>> >+			struct pci_dev *pdev;
>> >+
>> >+			if (!dev_is_pci(dev)) {
>> >+				dev_err(dev, "non-PCI device without a base
>address\n");
>> >+				return -EINVAL;
>> >+			}
>> >+
>> >+			pdev = to_pci_dev(dev);
>> >+			base_addr = pci_resource_start(pdev, (*header)->tbir);
>>
>> Alternate:
>>
>> if (!info->base_addr) {
>> 	struct pci_dev *pdev;
>>
>> 	if (!dev_is_pci(dev)) {
>> 		dev_err(dev, "non-PCI device without a base address\n");
>> 		return -EINVAL;
>> 	}
>>
>> 	pdev = to_pci_dev(dev);
>> 	info->base_addr = pci_resource_start(pdev, (*header)->tbir);}
>> }
>
>Thanks. I'll do this in the next patch.

Looking at one of your follow-on patches, I see that you are setting the info to const...

So setting the base_addr here, might not be "correct"?

M

>>
>> Would it make sense to require the caller to fill this in?
>>
>> i.e. if (!info->base_addr) return EINVAL?
>>
>> Change of behavior, but forcing the caller to provide the right info seems
>reasonable.
>
>Agreed. But that would be separate from this fixup patch.
>
>>
>> Either way, this looks reasonable to me.
>>
>> Reviewed-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
>
>Thanks
>
>David
>
>>
>> M
>>
>> >+		}
>> >+
>> >+		ret = intel_vsec_register_device(dev, *header, info, base_addr);
>> > 		if (ret)
>> > 			return ret;
>> > 	}
>> >
>> >base-commit: a167ae8eace52dd6c80438b77d92450fe12cd4be
>> >--
>> >2.43.0
>>