[PATCH AUTOSEL 4.4 19/65] x86/PCI: Mark Broadwell-EP Home Agent 1 as having non-compliant BARs

Sasha Levin
2018-10-25T14:17:43Z

From: Prarit Bhargava <prarit@redhat.com>

[ Upstream commit da77b67195de1c65bef4908fa29967c4d0af2da2 ]

Commit b894157145e4 ("x86/PCI: Mark Broadwell-EP Home Agent & PCU as having
non-compliant BARs") marked Home Agent 0 & PCU has having non-compliant
BARs. Home Agent 1 also has non-compliant BARs.

Mark Home Agent 1 as having non-compliant BARs so the PCI core doesn't
touch them.

The problem with these devices is documented in the Xeon v4 specification
update:

BDF2 PCI BARs in the Home Agent Will Return Non-Zero Values
During Enumeration

Problem: During system initialization the Operating System may access
the standard PCI BARs (Base Address Registers). Due to
this erratum, accesses to the Home Agent BAR registers (Bus
1; Device 18; Function 0,4; Offsets (0x14-0x24) will return
non-zero values.

Implication: The operating system may issue a warning. Intel has not
observed any functional failures due to this erratum.

Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e5-v4-spec-update.html
Fixes: b894157145e4 ("x86/PCI: Mark Broadwell-EP Home Agent & PCU as having non-compliant BARs")
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/pci/fixup.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
index 0ae7e9fa348d..89f90549c6a8 100644
--- a/arch/x86/pci/fixup.c
+++ b/arch/x86/pci/fixup.c
@@ -541,9 +541,16 @@ static void twinhead_reserve_killing_zone(struct pci_dev *dev)
}
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x27B9, twinhead_reserve_killing_zone);

+/*
+ * Broadwell EP Home Agent BARs erroneously return non-zero values when read.
+ *
+ * See http://www.intel.com/content/www/us/en/processors/xeon/xeon-e5-v4-spec-update.html
+ * entry BDF2.
+ */
static void pci_bdwep_bar(struct pci_dev *dev)
{
dev->non_compliant_bars = 1;
}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6f60, pci_bdwep_bar);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fa0, pci_bdwep_bar);
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fc0, pci_bdwep_bar);
--
2.17.1