From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F400738B147 for ; Fri, 21 Aug 2026 19:51:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787341883; cv=none; b=UQRa4wLsebXsCULoUXn2ggWr/fZuIVfmM0RfftsmnFCTdfXiw5X/j2OoHewMZK4REGTcPALTUlmmuDjvz5TKJ4IrkwxeUYB2N+38pvEH6Umyv7rBO4LOtu16jTaUhpgQ/Apb4u7C9hIJyHlF8plA5bfba7GKLB0D1VtTPsExyfE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787341883; c=relaxed/simple; bh=xsHZ/JcmCyKr3LkRYGLn9pBRkkBN+p9YhgVrESbc5QA=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=W9i8iLaNklH+t8hYnoQG0e/k2lTKL+ctVqEjCnVJ7u9Bo5Hu6GoG3XCYmUcMt9VJ4CPf3yfl7SMtEapfc2sInj9KnVlS59EZC1WHInuRrgP/JbMNUw1/+pqQNhdfkGxCj8BNOpI/Umnx+FyLiCCpRSptsxFhrg+5BLhrkUlJLR8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CY9C7sUh; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CY9C7sUh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 583A91F000E9; Fri, 21 Aug 2026 19:51:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787341881; bh=xsHZ/JcmCyKr3LkRYGLn9pBRkkBN+p9YhgVrESbc5QA=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=CY9C7sUhny8/IzseLOEaC1PKsVSOVf4xNzzB8Kpky+Xg/9PDVwSEZv1XSOjhjmTeO 6SE5P4fGC1k0Y3QkzbCjIMakKYrJih57x9LN/uS3Np0tE6eIJUi05W6RSIbCfUPgpm YFDm7pZeY5J1NHOb8ug0jxWozqcLmirnRB+BQSRDkZRu7oaYPZh31BzBFHFLcZhIoT 9ILAF6qbBI4bgF2TEwfACsbUtCD2S6qjPCuRvOvY/PHPWVdPQPAQvlLR+iLj+iC1JQ yFO4bYmGS8xk4JzCOMXpd90plAOJmEQyJIDl2YTjnWWuF55jvsXo91kPzZjEzylir8 qqsLfq5DlhVPA== From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 10/18] PCI: Account for ACS egress control in isolation checks Reply-To: sashiko-reviews@lists.linux.dev To: "Leon Romanovsky" Cc: linux-pci@vger.kernel.org In-Reply-To: <20260821-fix-p2p-acs-v4-0-v4-10-94426b96de73@nvidia.com> References: <20260821-fix-p2p-acs-v4-0-v4-0-94426b96de73@nvidia.com> <20260821-fix-p2p-acs-v4-0-v4-10-94426b96de73@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 21 Aug 2026 19:51:20 +0000 Message-Id: <20260821195121.583A91F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > From: Leon Romanovsky >=20 > pci_acs_enabled() treats P2P Request Redirect as effective whenever its > control bit is set. PCIe r7.0, sec 6.12.3, table 6-11 lets an enabled > Egress Control Vector override it: a clear vector bit routes the request > directly. >=20 > IOMMU grouping uses this check to prove peer requests cannot bypass the > IOMMU, but cannot know every applicable vector bit, so Request Redirect > gives no such guarantee while Egress Control is enabled. >=20 > Report Request Redirect as ineffective there, merging the devices into > one IOMMU group, and report no isolation when the register cannot be > read. Apply the same rule to the Intel SPT PCH quirk. >=20 > Unlike Direct Translated P2P this holds for an Untranslated Request too, > so it applies in both scopes. pci_enable_pasid() therefore fails on a > path where a port has Egress Control enabled, because Request Redirect > no longer shows that a Request carrying a PASID reaches the translation > agent. >=20 > Tested-by: Tushar Dave > Fixes: ad805758c0eb ("PCI: add ACS validation utility") > Reviewed-by: Logan Gunthorpe > Signed-off-by: Leon Romanovsky Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260821-fix-p2p-ac= s-v4-0-v4-0-94426b96de73@nvidia.com?part=3D10