From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793231505; b=aJ4muep4D3i9f6O9Z31TuVc1/tQKfK1e+WXWZuE+z1wWPU3o9ZumOc5Dg7eqRBqxhP+b drkNixoRDzH9Yt+37ewDMLYhXmSjradxKYoboIAzl9zihiWvNZZbzCILNyF3Z4gC4a1KH NChJx/Giv38+ryrQHK2wMNwqG9fs/2WAKGAkUnk5BW0H2NuqyaHLd/GqNbAbleFe+dRNI GUb9itbbJSqkqcTbRITy/6mWrYL+8BMESBOlW0u4J+Xctkh2nIGzqdzJ2nA+YGmwP58DP 1oE7LNl8Cx+oHSCd4ZRGTdkseIZnjC7JG0fxn5FQhvGH1XV56LOES7L0T8kvTbJvz2g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793231505; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=jWFhUYZCHiWYiadn3ltcY+PPcUKcRLuYQQ29kTBH2cY=; b=3zV4HNEk7FFmYnJ4VA1LJBQfc8svA5LOHqbSzymR0eRp8OkOoI4Ze+ZlpwntzoMHscWf uK2kKILqLHMz0RZeQT6KbqUfGbKlKuEjb6/yDI4thG/DpYZrEr/J6Ldq7ACTLBtoOB33b wjTDFWL388OYzqOSGPvd67edL2/+vk+2J79qC1yWWu+t1B9nstyEe4Ez7uJMaNulvTGiM reA1xsiffJoKzui3pJHUZo13BowX+gAhK51/Y2GlOGZPKGkMIWGVgAa/GZ/l5Wm4mk1Ky 6PPnicM1VyWJB2N53t8sLJOUIbV327tUIhD8Gc2hwrp1GkZQTT7pvKHvOWMCLu42Aow== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=GShce41l; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84E44606A31C for ; Wed, 28 Oct 2026 23:51:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=GShce41l Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EDB01F01825; Wed, 28 Oct 2026 23:51:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793231505; bh=jWFhUYZCHiWYiadn3ltcY+PPcUKcRLuYQQ29kTBH2cY=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=GShce41lxVZZM1A56TlHWeR6003ZJJpz7hi2q4MoNuQiiOnkZn6X7NfTLvCcm/ABN NZZVhNdaoJyAgCKw4vh2yoRrCkYVBxBGFdAH4f9lqtpvtnzclCeeCfSKbppie/mFeI UW5io1HlTkIJS8c7eD1ulUIZbtmCcKQNI5jNKV79CcK3UhS+M16iEyVnJGe+Nz3SZE kQoz3VWqzibm1F5Sl4gbMg/MfKiejmDLoqJmnzOuX9CcPQUsKNGEFcuLjB9LrQrhHD Cy+6uoSfVgVQaBC82RhxAFJmF6RX964ePaz630mK9KdNKDEUebRooUHhG8o/HUZn9f LhgzjQRuPZA6g== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2] PCI/ATS: Disable ATS when ACS TB is set upstream Reply-To: sashiko-reviews@lists.linux.dev To: "Danny Gonzalez" Cc: linux-pci@vger.kernel.org In-Reply-To: <20261028233651.960835-1-digonzal@google.com> References: <20261028233651.960835-1-digonzal@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 28 Oct 2026 23:51:44 +0000 X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > Enabling ATS allows an endpoint to cache translations and initiate DMA > requests with Translated addresses, which an upstream bridge with ACS > Translation Blocking (PCI_ACS_TB) set will block as ACS Violations. > Because pci_enable_acs() preserves existing PCI_ACS_CTRL bits (e.g., from > firmware, a kexec kernel, or "pci=3Dconfig_acs=3D") without relaxing them, > PCI_ACS_TB may remain set on upstream bridges. >=20 > Add pci_ats_check_acs() and call it from pci_dma_configure() after > pci_enable_acs() to walk upstream bridges and clear dev->ats_cap if any > bridge has PCI_ACS_TB enabled, leaving the endpoint to use Untranslated > addresses. >=20 > Tested by booting a machine with an endpoint advertising the ATS Capabili= ty > behind a Root Port with PCI_ACS_TB set; verified ATS is disabled and the > system boots cleanly. >=20 > Signed-off-by: Danny Gonzalez Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261028233651.9608= 35-1-digonzal@google.com?part=3D1