From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ale.deltatee.com (ale.deltatee.com [204.191.154.188]) (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 3D2123F6C3A; Tue, 4 Aug 2026 21:55:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=204.191.154.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785880526; cv=none; b=JUYUqUga7zojtS+OVe/3kUuVPmG6y2boYB7MiJG4O5JfseGFUYpD0WrbRaDyx2a5GFtIdkVZgDjx2FXGSKTtRrEiyLrNNQccTLMGwgpPbGOQJ7qc6Qn9hr8bVOkhUY6m88Z/Tz9bmCGsQV+f9EL3LR0BF+DCJjFs4hjJrlY2puE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785880526; c=relaxed/simple; bh=ArWBbRaQ7/lZELj8RsDbuShNnwKAqELRhIxTahqf1GU=; h=Message-ID:Date:MIME-Version:To:Cc:References:From:In-Reply-To: Content-Type:Subject; b=d0DsWkGGRM+FjBUpMc53yKzRk/vXgJsQHZqPxHqVIoRc+ghR2aukt1XFKxS5KxOrigept1kMC68CL064ikddtPehAy/SQw+547Ex2HAOGQBsWI/N2j4yMoAd9Ui1ni7OkGLvfIO5kRvF29llid8UMKlCRwdaH4Xl/Wt0tjZhuLo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=deltatee.com; spf=pass smtp.mailfrom=deltatee.com; dkim=pass (2048-bit key) header.d=deltatee.com header.i=@deltatee.com header.b=TLSB8sCh; arc=none smtp.client-ip=204.191.154.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=deltatee.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=deltatee.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=deltatee.com header.i=@deltatee.com header.b="TLSB8sCh" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:In-Reply-To:From:References:Cc:To: MIME-Version:Date:Message-ID:content-disposition; bh=YUUxkPTjKQu8APCYf6CHRMXTQxH1yyy9nZ/MELNNWvY=; b=TLSB8sCh/xs4nPSr/I4ebiIr9+ D20BxQZyhKj5avmWSVXCp6SH/2fiek0L2HjnAwB4SrUB6cZsI8tybrlsMbuYuqEnGyrrhiVGeIa1n /n50vmg8YF2Qrigtt9sHKW9dkR6mdhj5B8DWWdhzXG6VxX8h/Z+UY0F5fcCV1IZg0YcdLavxroy48 F9Swc0pJEAxs3ioYk3viajg4SUIL6VUsJMnABDxNF1pA/1HYhAGkBmS6/Czv78RMoTv8D7ImAUmUy 4O1SNTKeA4bzkvSbA/3Uku7liLgAUp7zE0IaBBgThTGhzmUjLJavQImN+wcxREoSCU3P1gT2NmS+8 pk2ROTEw==; Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.98.2) (envelope-from ) id 1wrN6Y-000000002Ry-48b2; Tue, 04 Aug 2026 15:55:23 -0600 Message-ID: Date: Tue, 4 Aug 2026 15:55:22 -0600 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Leon Romanovsky , Bjorn Helgaas , Jonathan Corbet , Shuah Khan , Alex Williamson Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org References: <20260802-fix-p2p-acs-v1-0-a7c5eb64fff6@nvidia.com> <20260802-fix-p2p-acs-v1-6-a7c5eb64fff6@nvidia.com> Content-Language: en-CA From: Logan Gunthorpe In-Reply-To: <20260802-fix-p2p-acs-v1-6-a7c5eb64fff6@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: leon@kernel.org, bhelgaas@google.com, corbet@lwn.net, skhan@linuxfoundation.org, alex@shazbot.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org X-SA-Exim-Mail-From: logang@deltatee.com X-Spam-Level: Subject: Re: [PATCH 06/13] PCI: Account for ACS egress control in isolation checks X-SA-Exim-Version: 4.2.1 (built Sun, 23 Feb 2025 07:57:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) On 2026-08-02 09:09, Leon Romanovsky wrote: > From: Leon Romanovsky > > 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. > > 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. > > 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. > > Signed-off-by: Leon Romanovsky Reviewed-by: Logan Gunthorpe