From 4fde448225123442c5796f54b7a4400e2d3cbaf6 Mon Sep 17 00:00:00 2001 From: Mario Limonciello Date: Tue, 8 Sep 2026 14:05:59 -0500 Subject: x86/PCI: Disable enhanced atomics on AMD NBIO 7.7 and 7.11 Multiple users report data corruption during 64-bit DMA transfers on systems with AMD NBIO 7.7 and 7.11 controllers. This occurs when BIOS enables AMD "enhanced atomic operations" on PCIe Root Ports. When enhanced atomics are enabled, any 64-bit DMA access may be corrupted. Disable enhanced atomics using SMN for NBIO 7.7 and 7.11 based models. Reported-by: Mikael Etienne Closes: https://lore.kernel.org/178789300872.392066.15963676631650361573@gmail.com/ Reported-by: Arthur Husband Closes: https://lore.kernel.org/20260406222335.379935-1-artmoty@gmail.com/ Reported-by: Alvin Lim Closes: https://lore.kernel.org/20260621100844.1224301-1-alvinwylim@gmail.com/ Signed-off-by: Mario Limonciello [bhelgaas: commit log, s/IOVA/DMA/ in comment] Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org Cc: David Laight Cc: John Smith Cc: Lennert Buytenhek Cc: Niklas Cassel Cc: Roland Waltersson Link: https://patch.msgid.link/20260908190600.226485-2-mario.limonciello@amd.com --- arch/x86/pci/fixup.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c index b301c6c8d..795d81c7a 100644 --- a/arch/x86/pci/fixup.c +++ b/arch/x86/pci/fixup.c @@ -886,6 +886,105 @@ static void quirk_clear_strap_no_soft_reset_dev2_f0(struct pci_dev *dev) } } DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x15b8, quirk_clear_strap_no_soft_reset_dev2_f0); + +/* + * Enhanced atomic operations can cause corruption with 64-bit DMA + * on these devices. + */ +#define RX_ENH_ATOMIC_EN BIT(8) + +static const u32 nbio_7_7_pcie_smn_addrs[] = { + 0x111401d0, + 0x111411d0, + 0x111421d0, + 0x111431d0, + 0x111441d0, + 0x112401d0, + 0x112411d0, + 0x112421d0, + 0x112431d0, + 0x112441d0, + 0x112451d0, + 0x113401d0, + 0x114401d0, +}; + +static const u32 nbio_7_11_pcie_smn_addrs[] = { + 0x112401d0, + 0x112411d0, + 0x112421d0, + 0x112431d0, + 0x112441d0, + 0x112451d0, + 0x113401d0, + 0x113411d0, + 0x113421d0, + 0x113431d0, + 0x113441d0, + 0x113451d0, +}; + +static void quirk_amd_nbio_enhanced_atomic(struct pci_dev *host_bridge, + const u32 *smn_addrs, + size_t nr_smn_addrs) +{ + bool changed = false; + size_t i; + u32 data; + int ret; + + for (i = 0; i < nr_smn_addrs; i++) { + ret = amd_smn_read(0, smn_addrs[i], &data); + if (ret) + continue; + if (!(data & RX_ENH_ATOMIC_EN)) + continue; + data = data & ~RX_ENH_ATOMIC_EN; + ret = amd_smn_write(0, smn_addrs[i], data); + if (ret) + continue; + if (changed) + continue; + ret = amd_smn_read(0, smn_addrs[i], &data); + if (ret) + continue; + if (data & RX_ENH_ATOMIC_EN) + continue; + changed = true; + } + + if (changed) + pci_info(host_bridge, "enhanced atomics disabled\n"); +} + +static void quirk_amd_nbio_7_7_disable_enhanced_atomic(struct pci_dev *dev) +{ + quirk_amd_nbio_enhanced_atomic(dev, nbio_7_7_pcie_smn_addrs, + ARRAY_SIZE(nbio_7_7_pcie_smn_addrs)); +} + +static void quirk_amd_nbio_7_11_disable_enhanced_atomic(struct pci_dev *dev) +{ + quirk_amd_nbio_enhanced_atomic(dev, nbio_7_11_pcie_smn_addrs, + ARRAY_SIZE(nbio_7_11_pcie_smn_addrs)); +} + +/* Phoenix, Hawk Point (NBIO 7.7) */ +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x14E8, + quirk_amd_nbio_7_7_disable_enhanced_atomic); +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x14E8, + quirk_amd_nbio_7_7_disable_enhanced_atomic); + +/* Strix, Krackan, Strix Halo (NBIO 7.11) */ +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x1507, + quirk_amd_nbio_7_11_disable_enhanced_atomic); +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x1507, + quirk_amd_nbio_7_11_disable_enhanced_atomic); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x1122, + quirk_amd_nbio_7_11_disable_enhanced_atomic); +DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x1122, + quirk_amd_nbio_7_11_disable_enhanced_atomic); + #endif /* -- cgit v1.3.1