From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4AE863A2544 for ; Thu, 4 Jun 2026 18:21:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780597289; cv=none; b=l/eu7djjNnkalPe50kqrzNA8JMGW1BmR396qiCKcAW2r822ZjIegI/YlrF+SQBcB67fmdO9EJs2ezS7mzStYnkmW5e3ixc/V7/hPrpDwoP2AdBrWUHdmFEXo7jc98TKnGgbcyZFQagTskNvCP0S0UVrHq0NVB90UgQK2Va9CUFc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780597289; c=relaxed/simple; bh=VqiZ8kNwgyZT1T7foVFsSLZBWEZ/w4HCqD6vFQ2562k=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ofY8mf+MiTXxiOw+NlWItjGOSxIlRytpnVKrSMfdnACPdx4AflnA9mkvxEQzSriRGE/EwM2+kVP4PgfvlVLnLfpJW3TXkEQuureDfaZ6pvu3bPnMuSEV/nfEqLuOSaYTKtjHB4wJFGJ+ybjidDqEFe4XsIWFw0xh/RDpyhB44Ok= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--praan.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=mXJ4KI7R; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--praan.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="mXJ4KI7R" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-2c0c36f1cc0so20629955ad.3 for ; Thu, 04 Jun 2026 11:21:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1780597285; x=1781202085; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=niiDq+FrdndFbib0XcxUBpiQEuQyYsWQAOjlvRNMMQM=; b=mXJ4KI7RCcB4+8NXPhstsC2CTTTn4EwW//jFLyE1PHXFXIDvdFYoStNm3CkMREzHxd hduPX0pN0r3k9LIqO4GJKzZKI1e/E9QI07vy9/NPe9DadBrWlr9YDXUKtzO/02lcutKy OErmYQA2pYNPRQZNDRKT0RCf/RyiXGEyv2hVXHL1O4buj6CjQMeM+wVQgkwtARrOruhw pP58s7zTwNToNrpF9jL6v44OjTYmG48m3EU5ta544OSvXZW9zbxgY0Ccf58rDnUY8ska yjRhSlEr+o4oacnmUDtKJQTfSPX1w3lIfEzHb0A87ZZAmLm3j/cMXQUmN6Ba3ALaab8e fQuQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780597285; x=1781202085; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=niiDq+FrdndFbib0XcxUBpiQEuQyYsWQAOjlvRNMMQM=; b=C7EDZqlh4SpfxOqPsjW/R/rw2U7bc4zydLuuFno/sYc+wVYa9IrQoMDOwu3bva8uDf a8FDN/YeOtxSndBEYjx4JLCfgpsmYwa5VuLwiMgsAvl2AC7qBqh0Kp6t+wiFxiXLoCDv qbETslkQNtSdzAr4pYSYYxV4bUlmhOd3/PsUuFySwoYrrrvM6TiCS2Yj+C62iH4NkT5G mzCS8XCkoL7fNrrNr31g50/SScFbS5dT5TPC9hlRyOx0amjRlThFo+hWfVxikrORsFDp zdQwseXe9szQFXS/eRw6Tz45RvjTUMSIUeI4bG6Pxv+UOGmn+0A9Ui0/38XnEMbzCITO hD0g== X-Forwarded-Encrypted: i=1; AFNElJ/LiOlhB57mh1uE65/+FM6FinDTfjpovrklzU48dEjBNSX26am0f/uy+f1dE1xAVlue8GBrvPOuD4MAYPE=@vger.kernel.org X-Gm-Message-State: AOJu0Yyc2rUeZ5rZhjQrdk/vhQiSQY8gAMKkReqIP073bphV8np1DRz2 acgAbPULaOp+O0c28rqPNSj+sZYzwfkSk3IJCYT85CFwNPcLknC2CAE+2J3murNsvhA2/RjBV1H n9Q== X-Received: from plbjz14.prod.google.com ([2002:a17:903:430e:b0:2ae:41d1:278d]) (user=praan job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:e74d:b0:2b4:5aff:de60 with SMTP id d9443c01a7336-2c163fa48efmr102370015ad.22.1780597284995; Thu, 04 Jun 2026 11:21:24 -0700 (PDT) Date: Thu, 4 Jun 2026 18:21:14 +0000 In-Reply-To: <20260604182116.3179005-1-praan@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260604182116.3179005-1-praan@google.com> X-Mailer: git-send-email 2.54.0.1032.g2f8565e1d1-goog Message-ID: <20260604182116.3179005-3-praan@google.com> Subject: [PATCH v8 2/4] PCI/ATS: Validate STU for VFs in pci_prepare_ats() From: Pranjal Shrivastava To: iommu@lists.linux.dev, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Joerg Roedel , Will Deacon , Robin Murphy , Baolu Lu , Jason Gunthorpe , Kevin Tian , Bjorn Helgaas , Samiullah Khawaja , Pranjal Shrivastava , Nicolin Chen Content-Type: text/plain; charset="UTF-8" While every PCI Function that implements ATS has an independent ATS Extended Capability structure with a Read/Write Smallest Translation Unit (STU) field, the kernel manages SR-IOV ATS by requiring the IOMMU driver to configure the STU on the Physical Function (PF) before any any Virtual Functions (VFs) are created. Currently, pci_prepare_ats() bails out early for VFs, assuming that the PF has already been correctly prepared. However, this creates a potential mismatch if a VF is subsequently prepared with a different page shift. Update pci_prepare_ats() to validate that the requested page shift (ps) matches the STU already configured in the associated PF. This ensures early detection of incompatible configurations and maintains the kernel's policy of consistent STU sizing across all functions associated with a given SMMU. Reviewed-by: Jason Gunthorpe Reviewed-by: Samiullah Khawaja Reviewed-by: Nicolin Chen Reviewed-by: Lu Baolu Reviewed-by: Kevin Tian Signed-off-by: Pranjal Shrivastava --- drivers/pci/ats.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c index 679a3c3c1d54..9cb23780093d 100644 --- a/drivers/pci/ats.c +++ b/drivers/pci/ats.c @@ -73,8 +73,12 @@ int pci_prepare_ats(struct pci_dev *dev, int ps) if (ps < PCI_ATS_MIN_STU) return -EINVAL; - if (dev->is_virtfn) + if (dev->is_virtfn) { + if (pci_physfn(dev)->ats_stu != ps) + return -EINVAL; + return 0; + } dev->ats_stu = ps; ctrl = PCI_ATS_CTRL_STU(dev->ats_stu - PCI_ATS_MIN_STU); -- 2.54.0.1032.g2f8565e1d1-goog