From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B35EEC4167B for ; Mon, 11 Dec 2023 17:38:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344753AbjLKRiX (ORCPT ); Mon, 11 Dec 2023 12:38:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344762AbjLKRiW (ORCPT ); Mon, 11 Dec 2023 12:38:22 -0500 Received: from mail-qk1-x730.google.com (mail-qk1-x730.google.com [IPv6:2607:f8b0:4864:20::730]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E60A8C3 for ; Mon, 11 Dec 2023 09:38:28 -0800 (PST) Received: by mail-qk1-x730.google.com with SMTP id af79cd13be357-77f3183f012so264503085a.0 for ; Mon, 11 Dec 2023 09:38:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1702316308; x=1702921108; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=Wx0kCWw6AOe/lnc+LPzU2mQddJvJBaAwvlRTrYIYzPQ=; b=pQdXciewmsgtALyJk0HPSa2sulwZcqaIVAMWqCWVNEoUnUiBhzdA7+QbQSxj7kCoKX T3vsa9O7n6fLGIQGAYazqwXtHt+UU+1zhzcWahozx3PzheIITZAroHgHsFLVKc8KYtvG HwojHl5R0Sg/6FYXY5nEXf17FwNsnVhR8OVlmKAEJdPnuJil938PxpIwR4vRzZgTMhHX 1uOIhBmqfgNcgU8djBfpWFQkSkVCf3x7UHtqiDhESx4/xfa/b0ZRT7lr9b7eNyRZ+Q1D nK+liXd/nMFqn+AHaE/zqHpp8yobOx6wJdNi3hlI4jVWspRczzSIitQ8ydwdmBBRCUuj 1s8w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702316308; x=1702921108; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Wx0kCWw6AOe/lnc+LPzU2mQddJvJBaAwvlRTrYIYzPQ=; b=T/L9bMZx2VQhKPUNu5PBuCvTlk1plHHl0gzHB/+0poWs6vShLLA60ylH8Bu8frL7qL uO34DrfGQs7BU15jD1YHXyonj3lOdNTlThPhLpj/2oeYyETxDQxph9EzThIMZa2/PADa KoiqxuI8O33hGkERIG4AfmHRspDtWqVFsf2/9TwnYDVqt8OKRGBawvxOdJ6ycC95dUE3 odX00OVX5Gfj3zGr28UG9T3gmqOGVYkbwvKiRvKakzdzZRJyaR1eRiaR5DOH1yuf02r+ nUC4dEyNSDrQH8/zWk8jeOOSAlFqMtWh08PNjdPozimdcMggYPnOtSNEbNOG9HlwqySS dfsg== X-Gm-Message-State: AOJu0YxngFUpRBpb9zjINC7tI1rWG4Liyu5KwFCvGdOQg4BAGnLYmJxl hpzQR4/4+WeoHvDcAhgNhhY1Dg== X-Google-Smtp-Source: AGHT+IFfc5Hv1E6FHOf1r8yAaQaGx0V3DuKRi/AlGBDjSOBNiyD2/IhGz/2tIGlgla1T0f8Y1D++jA== X-Received: by 2002:a05:620a:95b:b0:77f:37b2:21e4 with SMTP id w27-20020a05620a095b00b0077f37b221e4mr5503877qkw.38.1702316308081; Mon, 11 Dec 2023 09:38:28 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-134-23-187.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.134.23.187]) by smtp.gmail.com with ESMTPSA id 11-20020a05620a04cb00b0077f529e7d23sm1624685qks.29.2023.12.11.09.38.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 09:38:27 -0800 (PST) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1rCkEc-00CdZD-R2; Mon, 11 Dec 2023 13:38:26 -0400 Date: Mon, 11 Dec 2023 13:38:26 -0400 From: Jason Gunthorpe To: Lu Baolu Cc: Joerg Roedel , Will Deacon , Robin Murphy , Kevin Tian , iommu@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/6] iommu/vt-d: Setup scalable mode context entry in probe path Message-ID: <20231211173826.GE1489931@ziepe.ca> References: <20231205012203.244584-1-baolu.lu@linux.intel.com> <20231205012203.244584-2-baolu.lu@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231205012203.244584-2-baolu.lu@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 05, 2023 at 09:21:58AM +0800, Lu Baolu wrote: > +/* > + * Get the PASID directory size for scalable mode context entry. > + * Value of X in the PDTS field of a scalable mode context entry > + * indicates PASID directory with 2^(X + 7) entries. > + */ > +static unsigned long context_get_sm_pds(struct pasid_table *table) > +{ > + unsigned long pds, max_pde; > + > + max_pde = table->max_pasid >> PASID_PDE_SHIFT; > + pds = find_first_bit(&max_pde, MAX_NR_PASID_BITS); > + if (pds < 7) > + return 0; > + > + return pds - 7; This seems like a convoluted way to write max(ilog2(table-max_pasid) - 7,0) ? Jason