From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1749B165F1F; Mon, 6 Jan 2025 20:53:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736196810; cv=none; b=qpOWttTqdsS7TnABq9xGC0+ikIz3GJItQ6ThjaVEGP2aJ+Gw4A9D6J4wB0UBZXTusaWMvU39UkeiMVEmCGkapH89ji4RF+QP16fXajIEwrvYvwgmVlrS8P9EtEW/JRyOxOw4s2KAT86LEC2K5kimiiXDCsVQkkDMIJpU/3aLe+g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736196810; c=relaxed/simple; bh=r/lfglIrDThqxuly3fukfGmtqm6TbeIeyw+2/SeAMEY=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=WQ0tqeR/goPrMKdikRWDhjL0/7j0VmNN6S12vxxNcTYbqcVBXKfkR36F/bLHJhQpr9bOqcegStT0uNNf37adBmEd2vRBWFpJZN1nkZB/L4v6v2Bv+DMpaR2s+Md2agK+3Y6RYb2TbkiLlohfxIJh2wrV9FWJMJ16Ks6r2/kgFt0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gRb3+ps0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gRb3+ps0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F8FFC4CED2; Mon, 6 Jan 2025 20:53:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736196809; bh=r/lfglIrDThqxuly3fukfGmtqm6TbeIeyw+2/SeAMEY=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=gRb3+ps0pnMrZ6D5v/J1BQRljAb6opb+hwRBgw1EDK7rw2ytvzbFGEREbGoIHbmY7 YDbdKV526BOAb0gLedVPgHLLlu/1aiNvkKlssO+eHQuCoGS9KxAijJsNFajSy8qvg+ +8SK76ROhkclcg7+477D1FM8Q+pBK6YwsMI+wFep6jItDPGW7RUfkJpy1DgiPpHxrf GrAN58Ms5xY4Taw16AE/ZUXXCONKDb4sZDqaNRCC8WBBit2vBKM7pbGKXkupmrUEkK 6rh/Edr7+/KNr5ruymwjcC7o980ZHTJ2kJZnkMfZeHfMZ/RMQTzEj3h6hY7CC9M4uf 2a/26reAdpz4w== Date: Mon, 6 Jan 2025 14:53:26 -0600 From: Bjorn Helgaas To: Tushar Dave Cc: Jason Gunthorpe , corbet@lwn.net, bhelgaas@google.com, paulmck@kernel.org, akpm@linux-foundation.org, thuth@redhat.com, rostedt@goodmis.org, xiongwei.song@windriver.com, vidyas@nvidia.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, vsethi@nvidia.com, sdonthineni@nvidia.com Subject: Re: [PATCH 1/1] PCI: Fix Extend ACS configurability Message-ID: <20250106205326.GA132024@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2676cf6e-d9eb-4a34-be5e-29824458f92f@nvidia.com> On Mon, Jan 06, 2025 at 12:34:00PM -0800, Tushar Dave wrote: > On 1/2/25 10:40, Jason Gunthorpe wrote: > > On Fri, Dec 13, 2024 at 12:29:42PM -0800, Tushar Dave wrote: > > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > > index dc663c0ca670..fc1c37910d1c 100644 > > > --- a/Documentation/admin-guide/kernel-parameters.txt > > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > > @@ -4654,11 +4654,10 @@ > > > Format: > > > @[; ...] > > > Specify one or more PCI devices (in the format > > > - specified above) optionally prepended with flags > > > - and separated by semicolons. The respective > > > - capabilities will be enabled, disabled or > > > - unchanged based on what is specified in > > > - flags. > > > + specified above) prepended with flags and separated > > > + by semicolons. The respective capabilities will be > > > + enabled, disabled or unchanged based on what is > > > + specified in flags. > > > ACS Flags is defined as follows: > > > bit-0 : ACS Source Validation > > > @@ -4673,7 +4672,7 @@ > > > '1' – force enabled > > > 'x' – unchanged > > > For example, > > > - pci=config_acs=10x > > > + pci=config_acs=10x@pci:0:0 > > > would configure all devices that support > > > ACS to enable P2P Request Redirect, disable > > > Translation Blocking, and leave Source > > > > Is this an unrelated change? The format of the command line shouldn't > > be changed to fix the described bug, why is the documentation changed? > > The documentation as it is (i.e. without my patch), is not correct. > > IOW, config_acs parameter does require flags and it is not optional. Without > flags it results into "ACS Flags missing". Therefore I remove word > "optionally" from the documentation text. > > Secondly, the syntax in the example 'pci=config_acs=10x' is incorrect. The > correct syntax should be 'pci=config_acs=10x@pci:0:0' that would configure > all devices that support ACS to enable P2P Request Redirect, disable > Translation Blocking, and leave Source Validation unchanged from whatever > power-up or firmware set it to. I'd suggest a separate patch to fix the documentation so we don't try to relate the doc changes with the code changes.