From 16 October 2026 P2P kernel work
Subject: PCI/P2PDMA: whitelist Intel host bridge 8086:4621

This is a minimal reconstruction of the whitelist change from the recorded
kernel work. It is based on the exact added entry and target file supplied in
the research notes; surrounding patch metadata from the original working tree
was not preserved.

The REQ_SAME_HOST_BRIDGE flag keeps the existing same-host-bridge constraint.
It does not disable the kernel's other PCI P2P topology and ACS checks.

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -510,4 +510,5 @@ static const struct pci_p2pdma_whitelist_entry {
 	{PCI_VENDOR_ID_INTEL,	0x2f00, REQ_SAME_HOST_BRIDGE},
 	{PCI_VENDOR_ID_INTEL,	0x2f01, REQ_SAME_HOST_BRIDGE},
+	{ PCI_VENDOR_ID_INTEL, 0x4621, REQ_SAME_HOST_BRIDGE },
 	/* Intel Skylake-E */
 	{PCI_VENDOR_ID_INTEL,	0x2030, 0},