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 3CAC643C05E; Mon, 21 Sep 2026 20:38:17 +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=1790023098; cv=none; b=MdhbMRAYOyPbg1WTDhVvGKt1rVk0TaOtPBODmS9nWGgpIB7TV8Q9+rC25Xb8Vbj+ohFYo/hJYHVOOVHPbma6+bVm4gnSiCjUrYcfAgYSPmX1VhyYP1oNKRNxose4YbIt79bsSdXYmjretTYfj5VpqMoOl9IogfghcNyAfLvPOnc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790023098; c=relaxed/simple; bh=eYmGtKrob21NWMfAQ95fckRcqt+uVQGfzglKt7C19oY=; h=Message-ID:Date:MIME-Version:To:Cc:References:From:In-Reply-To: Content-Type:Subject; b=pKg6Yuy3JSX4L0i9/qJpafn/LlVrsgI89UMvjm9Y1vbyWzizmSftZqNh94nwvaOoAG7MEajMEKnoeCNqfc1NkeRKQa8JHfJZV2R5fZ5ESjjoQ8jB/7AWzHXFPz4mO16gfOdVWA4UWiVasJg2RhTkLxd+Qf0neJ4GQ1nQPnEKL3g= 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=LsKW3NzD; 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="LsKW3NzD" 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=Sr1qhGABu2EZeNtmrODjYoKQgc9j8cv9j73nR1L57ck=; b=LsKW3NzDV8inZjUq6NrZSEC48G 3MkUOffQBf7rtALq+krqCwpV4UHCjoTxdPFsIP8DFtXqvVKwEioT1Cdn1lv1P9SzDVlrBFfG/XMZ9 Fs03BSlR0j2+oZ4iyoY2LAwViJLntqOIDaG99B+Erxl9MgSfArvsxm3puFumHsbCbSidz+laCrr9K 8DCBlV4VsoMt/nH4fzRJvjoz0nSwjx+ljCmCLmhG72sIgW+ojj6vQGUn/R2jITMzh4crlfd+5z1su tkZIOwSo9KaAJ9LTeZSR6M/eAK9dh0+CHIrd73lTZSfUpRtEPAnWBq1cjcaQl3lo6AdZ4NFJhYILD LsDqJvHQ==; 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 1x8kmC-0000000F4jb-3Od7; Mon, 21 Sep 2026 14:38:13 -0600 Message-ID: <81c888b7-5d43-42cb-87ea-273e169d8343@deltatee.com> Date: Mon, 21 Sep 2026 14:38:09 -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 , Chaitanya Kulkarni , Greg Kroah-Hartman , Jens Axboe , Alex Williamson , Ankit Agrawal , Jason Gunthorpe , Jonathan Corbet , Shuah Khan , "Joerg Roedel (AMD)" , Will Deacon , Robin Murphy , Randy Dunlap , Sumit Semwal , =?UTF-8?Q?Christian_K=C3=B6nig?= Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, iommu@lists.linux.dev, Tushar Dave , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-rdma@vger.kernel.org, kvm@vger.kernel.org References: <20260920-fix-p2p-acs-v4-0-v7-0-ca0828ab697c@nvidia.com> <20260920-fix-p2p-acs-v4-0-v7-9-ca0828ab697c@nvidia.com> Content-Language: en-CA From: Logan Gunthorpe In-Reply-To: <20260920-fix-p2p-acs-v4-0-v7-9-ca0828ab697c@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, kch@nvidia.com, gregkh@linuxfoundation.org, axboe@kernel.dk, alex@shazbot.org, ankita@nvidia.com, jgg@ziepe.ca, corbet@lwn.net, skhan@linuxfoundation.org, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com, rdunlap@infradead.org, sumit.semwal@linaro.org, christian.koenig@amd.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, iommu@lists.linux.dev, tdave@nvidia.com, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-rdma@vger.kernel.org, kvm@vger.kernel.org X-SA-Exim-Mail-From: logang@deltatee.com X-Spam-Level: Subject: Re: [PATCH v7 09/19] PCI/P2PDMA: Reject Translated Requests blocked by Translation Blocking 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 2026-09-20 05:41, Leon Romanovsky wrote: > From: Leon Romanovsky > > A Downstream Port with ACS Translation Blocking enabled treats every > Upstream Memory Request whose Address Type is not Untranslated as an ACS > Violation, ahead of "any applicable ACS P2P control mechanisms" per PCIe > r7.0 sec 6.12.1.1. P2PDMA never looks at that bit, so it reports a > bus-addressable path where an ATS client's Requests would be rejected. > > Add PCI_ACS_P2PDMA_BLOCKED, and because blocking is not a routing control, > scan the path for it rather than the divergence port alone. A blocked > Request has no host bridge fallback, since the Address Type is rejected > wherever the Request is addressed. > > The two routes do not pass the same ports, so scan them separately. A > direct route turns around at the divergence and only passes the ports > below it, while the host bridge route keeps climbing and passes that port > and everything above it as well. > > Tested-by: Tushar Dave > Signed-off-by: Leon Romanovsky > +/* > + * Report whether any port between @client and @common rejects Translated > + * addresses. @common is NULL to walk every port up to the host bridge. A port > + * whose ACS Control cannot be read counts as blocking, which withdraws only > + * the Translated classes because an Untranslated Request is routed by the > + * redirect controls instead. > + */ Some awkward wording, maybe: "If @common is NULL, every port up to the host bridge is walked." Besides that minor nit: Reviewed-by: Logan Gunthorpe