From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 E6D213B52EA; Wed, 6 May 2026 22:06:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778105204; cv=none; b=n4nYOPHjySCII9a12cfOWS41zOibUP1WVQtF2wv4GCPQk9Lpz9aUXiVof9oY4wds8CQm3a+7hCNJR4YfFi8/7vktejXm4ghiE/vQXK5H7TdGuoEMPynUz9vw3ccP/1b2jd1rlNju/oxHGi3mp+kz8+NU3dYhh2Ws723dS+xCFUQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778105204; c=relaxed/simple; bh=JTusYyNLA22gY11bCtDchSj/wTcpsrskdCGVYwigaZg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=hOi2krMw655RKmbJbnnTvlflsJ/lsrcnkF2dy1KkiGWTFfS7B/nRfE1rKjeplbNcyYqAxryDN6pieSmAZP+pUB6a8HDSYj45R4PlJY8CS7VB14z1KTBFaon0cLjMLR0gJ2wBICpOPHSQaYRBdnFGo7ynPa04RFu0EHiwyjy1Xrc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=HljAvGz4; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="HljAvGz4" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Sender:Reply-To:Content-ID:Content-Description; bh=vTlOLeIdQpCjv7UhS84C4IGjj5+hiOQHx/OYcjnThOU=; b=HljAvGz4gMMAvypsS14xsOBZga dAW6uoihhLT7Lc58XydWuRc8nOcmhOKbzgw7/NjneYqQaoD40XPQ0NN8KcTnpIt2Ok45ah8reXArd +yTOflZbLHWmg64Dy9Gi+aDkapCp8jxAtgSpvlmtyz07tysZDWhl92zc8oO+EGwfj/lZU0fEEiEYS rXOdMztrrURxyyXAtLsC5LkbAvoDcN4Gsi8OqWMwuQDPyGEpWc3l6MM8ArlQ8YCs32Zau9fZzPyU+ 0g80BLx/nnAwGqO352bwqYebD/1RZnzKHioJlfK5xr5nwwNj9vCTh/fL5fNz/I1Tw1n8rpIQx+xsC xuUWtSAQ==; Received: from [50.53.43.113] (helo=[192.168.254.34]) by bombadil.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wKkNj-00000002A0U-3R8g; Wed, 06 May 2026 22:06:15 +0000 Message-ID: <649c67bb-be03-4843-ac2f-19f4eeabef54@infradead.org> Date: Wed, 6 May 2026 15:06:14 -0700 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 2/6] Documentation/kernel-parameters: Add multi-device config_acs example To: Wei Wang , bhelgaas@google.com, jgg@nvidia.com, jonathan.cameron@huawei.com, dan.carpenter@linaro.org, akpm@linux-foundation.org, bp@alien8.de, alex@shazbot.org, kevin.tian@intel.com, manivannan.sadhasivam@oss.qualcomm.com Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org References: Content-Language: en-US From: Randy Dunlap In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi, On 5/6/26 7:10 AM, Wei Wang wrote: > The config_acs parameter allows configuring ACS settings for multiple PCI > devices by separating entries with semicolons. The current documentation > only illustrates applying one configuration pattern to all devices, but > does not show how to specify multiple devices with different ACS settings > in a single parameter. Add an example demonstrating multi-device usage > with distinct ACS configurations. > > Some bootloaders interpret ';' as a command separator, which can cause > the parameter to be split as multiple commands. Document that the entire > parameter may need to be quoted to avoid bootloader parsing issues. This > avoids confusing bootloader errors such as β€˜can't find command ’ > when passing multiple device entries. > > Signed-off-by: Wei Wang > Reviewed-by: Jason Gunthorpe > --- > Documentation/admin-guide/kernel-parameters.txt | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 170aae226e2e..0c159ab59e14 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -5277,15 +5277,20 @@ Kernel parameters > '1' – force enabled > 'x' – unchanged > For example, > - pci=config_acs=10x@pci:0:0 > + - pci=config_acs=10x@pci:0:0 Are these added hyphens/dashes helpful? Are they needed for some reason? I don't see any problem here without the leading '-'. They (here and below) seem like they could add some confusion IMO. > 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. > - > Note: this may remove isolation between devices > and may put more devices in an IOMMU group. > + - 'pci=config_acs=10x@0000:04:00.0;1x101@0000:84:00.0' > + configures two devices with different ACS settings. > + Note: Some bootloaders interpret ';' as a command > + separator. If so, quote the entire parameter to > + ensure it is passed to the kernel unchanged. > + > force_floating [S390] Force usage of floating interrupts. > nomio [S390] Do not use MIO instructions. > norid [S390] ignore the RID field and force use of -- ~Randy