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Wed, 15 Jul 2026 13:24:29 -0700 (PDT) Received: from twshared19691.04.snb1.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c08b:78::c78f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.2562.41; Wed, 15 Jul 2026 20:24:27 +0000 Received: by devbig259.ftw1.facebook.com (Postfix, from userid 664516) id 8CC1A423A594F; Wed, 15 Jul 2026 13:24:10 -0700 (PDT) From: Zhiping Zhang To: Bjorn Helgaas , CC: Christian Konig , Alex Williamson , , , Zhiping Zhang Subject: [PATCH v2] PCI/TPH: fold reserved completer encoding in get_rp_completer_type() Date: Wed, 15 Jul 2026 13:24:00 -0700 Message-ID: <20260715202409.3767494-1-zhipingz@meta.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzE1MDIwMiBTYWx0ZWRfX1vmFbxWMY8Cc 7lVLuFY7PO6qWCNFaXxg2+uopiZOyCUghjbIAacGoWyaaqG+bEI/lhDtwvYdCQQJyWQD4mXiwzy ZlPiHYsx9fIGaXDjmC2jCMfwV59MKVsjuuibFt7wkRnfFYDLjiFG5Mh3DqI1e66n2yHAhICHiFF RuQT1prvAkFPGqm/0r2ICV8ntXMqTcPJjBa1IpsQOhIp0eujUHceAfDzT0ciYyaOG2dqpSyJVAI nLM7NMwhjXzruZQ9D5uJSYdi35wdTe49FwoqEbkYPAbEo/KWBsiMResovLYcQSCumObnH9m7AK+ M3tfqjOLvoRliTo1tR1JrNhbow0P8rK+O4ccF0a3IFH+tPuAta4ZxYulBbxdSIBnD6nof8hAShJ UsZelAE30hoN/nzyrG7XYWUXOVgQ4tnW7DTd7/c0TG8dy2jxJKJB0O5xgcTmxJU1mcVkBDwZS26 MK0eZn+iV88ds+jWs8Q== X-Authority-Analysis: v=2.4 cv=O+kJeh9W c=1 sm=1 tr=0 ts=6a57ec7d cx=c_pps a=CB4LiSf2rd0gKozIdrpkBw==:117 a=CB4LiSf2rd0gKozIdrpkBw==:17 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=7x6HtfJdh03M6CCDgxCd:22 a=_1IyUuN4QrATX339ibzo:22 a=VabnemYjAAAA:8 a=10P_XigQlVKDyM0i7pYA:9 a=gKebqoRLp9LExxC7YDUY:22 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzE1MDIwMiBTYWx0ZWRfX2M/2jpQzEzt4 906jtNjcAkNaARtDvonKgKwJrZKXhRMNHdIxnv0XG+f1pD3yirbdJEmKADXm6KWDl0ILBUs6TPW blaBqMCkaB4U10dmrsmYXxYlNmIF6pc= X-Proofpoint-ORIG-GUID: 1kjXlrS2mFh2Rcu-IQFGZxF-2hkjaLur X-Proofpoint-GUID: 1kjXlrS2mFh2Rcu-IQFGZxF-2hkjaLur X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-15_04,2026-07-15_02,2025-10-01_01 Content-Type: text/plain; charset="utf-8" get_rp_completer_type() returns the Root Port's "TPH Completer Supported" field (bits 13:12 of Device Capabilities 2) verbatim. The 0b10 encoding is reserved, but pcie_enable_tph() feeds the raw value into the requester type: pdev->tph_req_type =3D min(pdev->tph_req_type, rp_req_type); and later writes tph_req_type to the TPH Requester Enable field, which only defines 0b00 (disable), 0b01 (TPH only) and 0b11 (extended TPH). If a Root Port ever presents the reserved 0b10, that value could be written back to hardware, risking undefined behavior. Fold the reserved encoding into "not supported" so only the three defined values can propagate. Fixes: f69767a1ada3 ("PCI: Add TLP Processing Hints (TPH) support") Signed-off-by: Zhiping Zhang --- drivers/pci/tph.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/pci/tph.c b/drivers/pci/tph.c index 655ffd60e62f..ebe1aa5ba5eb 100644 --- a/drivers/pci/tph.c +++ b/drivers/pci/tph.c @@ -196,6 +196,21 @@ u16 pcie_tph_get_st_table_size(struct pci_dev *pdev) } EXPORT_SYMBOL(pcie_tph_get_st_table_size); =20 +/* + * Fold the reserved 0b10 "TPH Completer Supported" encoding into + * "not supported" so only the three defined values propagate. + */ +static u8 tph_completer_type_fold(u8 comp) +{ + switch (comp) { + case PCI_EXP_DEVCAP2_TPH_COMP_TPH_ONLY: + case PCI_EXP_DEVCAP2_TPH_COMP_EXT_TPH: + return comp; + default: + return PCI_EXP_DEVCAP2_TPH_COMP_NONE; + } +} + /* Return device's Root Port completer capability */ static u8 get_rp_completer_type(struct pci_dev *pdev) { @@ -211,7 +226,8 @@ static u8 get_rp_completer_type(struct pci_dev *pdev) if (ret) return 0; =20 - return FIELD_GET(PCI_EXP_DEVCAP2_TPH_COMP_MASK, reg); + return tph_completer_type_fold(FIELD_GET(PCI_EXP_DEVCAP2_TPH_COMP_MASK, + reg)); } =20 /* Write tag to ST table - Return 0 if OK, otherwise -errno */ --=20 2.53.0-Meta