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Mon, 25 May 2026 11:44:00 -0700 (PDT) Date: Mon, 25 May 2026 18:43:46 +0000 In-Reply-To: <20260525184347.4059549-1-praan@google.com> Mime-Version: 1.0 References: <20260525184347.4059549-1-praan@google.com> X-Mailer: git-send-email 2.54.0.746.g67dd491aae-goog Message-ID: <20260525184347.4059549-5-praan@google.com> Subject: [PATCH v4 4/5] iommu/vt-d: Fail probe on ATS configuration failure From: Pranjal Shrivastava To: iommu@lists.linux.dev, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Joerg Roedel , Will Deacon , Bjorn Helgaas , David Woodhouse , Lu Baolu , Robin Murphy , Suravee Suthikulpanit , Jason Gunthorpe , Nicolin Chen , David Matlack , Samiullah Khawaja , Daniel Mentz , Pasha Tatashin , Mostafa Saleh , Pranjal Shrivastava Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260525_114401_561739_030F09A2 X-CRM114-Status: GOOD ( 14.65 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Update the Intel VT-d driver to handle ATS configuration and enablement more strictly. Specifically, update the device probe to fail if pci_prepare_ats() returns an error. This ensures that any ATS-capable master reaching the attach phase is guaranteed to have a valid config. Additionally, update iommu_enable_pci_ats() to WARN() if pci_enable_ats fails. Since earlier checks in the probe phase preclude config-related failures, any failure during hardware enablement is considered a kernel bug. Signed-off-by: Pranjal Shrivastava --- drivers/iommu/intel/iommu.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 4d0e65bc131d..22308e4911e1 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -873,8 +873,14 @@ static void iommu_enable_pci_ats(struct device_domain_info *info) if (!pci_ats_page_aligned(pdev)) return; - if (!pci_enable_ats(pdev, VTD_PAGE_SHIFT)) - info->ats_enabled = 1; + /* + * pci_enable_ats() should not fail here because earlier checks + * have already verified support and configuration. + */ + if (WARN_ON(pci_enable_ats(pdev, VTD_PAGE_SHIFT))) + return; + + info->ats_enabled = 1; } static void iommu_disable_pci_ats(struct device_domain_info *info) @@ -3288,7 +3294,10 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev) dev_iommu_priv_set(dev, info); if (pdev && pci_ats_supported(pdev)) { - pci_prepare_ats(pdev, VTD_PAGE_SHIFT); + ret = pci_prepare_ats(pdev, VTD_PAGE_SHIFT); + if (ret) + goto free; + ret = device_rbtree_insert(iommu, info); if (ret) goto free; -- 2.54.0.746.g67dd491aae-goog