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 158B824E01D for ; Mon, 15 Sep 2025 16:04:49 +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=1757952291; cv=none; b=JkKjDtDFbqh1tsu5xIaIjgqxZRIo6jiG1Z/Kqsj5Tj4Nx+F1ZYhQ8ukm0QgG6b62MFxKHxnFuqSTLRT4Yr5EIYBRX2hvoqZxFvruyAukx58w7t8KTjhhZG2fO99uWTTK5bYA7Nv0BZtJFGpoYaQONMx+kKav9UzVqR76Wmn9ZN8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757952291; c=relaxed/simple; bh=qZak0IWjTFvTEZDlBi5GLG7k8WDKzZb2UcXYudM6lak=; h=Message-ID:Date:MIME-Version:To:Cc:References:From:In-Reply-To: Content-Type:Subject; b=UjSD4IYuVgnyywsY8GbfOluVK2tRu1S5AjBK4kZLNe71irAqQ5q4ceDzPe9BrJpl/SCes4nBkTYLY52e0tXlXu64FjQ1RfNlqfqUc90km23lCWKHxSqVo723AklDbEYyjRnxOtMtfGccz9WrKwvKHQ7Ccm945/kcIRKtnjOpnUA= 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=WwuuRcgj; 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="WwuuRcgj" 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=ct6Q6jd9bg2f3Yaega2w/3bt4lVQ8RUfwQj2iLKeA0k=; b=WwuuRcgjKBfqMAdgftjSrkdCkd E98/p++osXW2XuK5DOyzTWeE+Id+csr7dnCOVTrW+zFjN0Zu0iPuuMWA8/wXxnNULDNJMe0oFmllW cHxMDutsK1cIl9fCp8UU4DvJhE9X93FfzSZn8bqda2lzpUH2EEfzCjiL5YLIpCbpR0yxtXJN+B1kO npoljLq5CyW84ZgE25L6yyivVlJ6qyPj7JiE0B8pl/gkXm5W7DMETtZp7AduSvCFm5rXQ2YmZwQaS LqGLFU4FB55rvQgSQWnc/umArpQUfxB4PI5PQGtACojtsQiUffX7029YRu6kf9RiXlmmDZPlGqjen L2YESB+A==; 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 4.96) (envelope-from ) id 1uyBCk-005CIr-1L; Mon, 15 Sep 2025 09:33:22 -0600 Message-ID: <7cb11157-4b77-407d-ac48-7e75dc01a7a3@deltatee.com> Date: Mon, 15 Sep 2025 09:33:19 -0600 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Vivek Kasireddy , dri-devel@lists.freedesktop.org, intel-xe@lists.freedesktop.org Cc: Bjorn Helgaas , linux-pci@vger.kernel.org References: <20250915072428.1712837-1-vivek.kasireddy@intel.com> <20250915072428.1712837-2-vivek.kasireddy@intel.com> Content-Language: en-CA From: Logan Gunthorpe In-Reply-To: <20250915072428.1712837-2-vivek.kasireddy@intel.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: vivek.kasireddy@intel.com, dri-devel@lists.freedesktop.org, intel-xe@lists.freedesktop.org, bhelgaas@google.com, linux-pci@vger.kernel.org X-SA-Exim-Mail-From: logang@deltatee.com X-Spam-Level: Subject: Re: [PATCH v4 1/5] PCI/P2PDMA: Don't enforce ACS check for device functions of Intel GPUs X-SA-Exim-Version: 4.2.1 (built Wed, 06 Jul 2022 17:57:39 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) On 2025-09-15 01:21, Vivek Kasireddy wrote: > Typically, functions of the same PCI device (such as a PF and a VF) > share the same bus and have a common root port and the PF provisions > resources for the VF. Given this model, they can be considered > compatible as far as P2PDMA access is considered. > > Currently, although the distance (2) is correctly calculated for > functions of the same device, an ACS check failure prevents P2P DMA > access between them. Therefore, introduce a small function named > pci_devfns_support_p2pdma() to determine if the provider and client > belong to the same device and facilitate P2PDMA between them by > not enforcing the ACS check. > > However, since it is hard to determine if the device functions of > any given PCI device are P2PDMA compatible, we only relax the ACS > check enforcement for device functions of Intel GPUs. This is > because the P2PDMA communication between the PF and VF of Intel > GPUs is handled internally and does not typically involve the PCIe > fabric. > > Cc: Bjorn Helgaas > Cc: Logan Gunthorpe > Cc: > Signed-off-by: Vivek Kasireddy This looks good to me, thanks. Reviewed-by: Logan Gunthorpe