From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH v5 2/6] arm64: Introduce VA_BITS and translation level options Date: Fri, 2 May 2014 04:16:48 -0700 Message-ID: <20140502111648.GA3002@lvm> References: <000201cf64e5$cd3366a0$679a33e0$@samsung.com> <20140501100628.GB2848@lvm> <000a01cf65a9$d3cbf030$7b63d090$@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-lb0-f178.google.com ([209.85.217.178]:48423 "EHLO mail-lb0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751909AbaEBLQw (ORCPT ); Fri, 2 May 2014 07:16:52 -0400 Received: by mail-lb0-f178.google.com with SMTP id 10so2895620lbg.23 for ; Fri, 02 May 2014 04:16:50 -0700 (PDT) Content-Disposition: inline In-Reply-To: <000a01cf65a9$d3cbf030$7b63d090$@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Jungseok Lee Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, Catalin.Marinas@arm.com, 'Marc Zyngier' , linux-kernel@vger.kernel.org, 'linux-samsung-soc' , steve.capper@linaro.org, sungjinn.chung@samsung.com, 'Arnd Bergmann' , kgene.kim@samsung.com, ilho215.lee@samsung.com On Fri, May 02, 2014 at 10:57:09AM +0900, Jungseok Lee wrote: > On Thursday, May 01, 2014 7:06 PM, Christoffer Dall wrote: > > On Thu, May 01, 2014 at 11:33:56AM +0900, Jungseok Lee wrote: [...] > > > + > > > +choice > > > + prompt "Virtual address space size" > > > + default ARM64_VA_BITS_39 if ARM64_4K_PAGES > > > + default ARM64_VA_BITS_42 if ARM64_64K_PAGES > > > + help > > > + Allows virtual address space size. A level of translation tables > > > > What does "Allows virtual address space size" mean exactly? > > It means that VA space size can be chosen. For example, there are > two VA size options, 39-bit and 48-bit, with 4KB pages. If 39-bit > VA space is not enough, 48-bit can be selected instead. The 5th patch > adds a 48-bit option to this choice blocks. > > If 16KB pages are supported with both 47-bit and 48-bit VA size, > people could configure it in menuconfig. > > In this context, I've written it down like page size. > > I think Catalin's comment would be helpful. > http://www.spinics.net/linux/lists/arm-kernel/msg319552.html > I didn't have problems understanding the concept, I was questioning the language. The way it is written now it suggests having a virtual address space size, as opposed to not having a size at all, which doesn't make sense. I think you want to say something along the lines of "Allows choosing a virtual address space size", or "Allows choosing one of multiple possible virtual address space sizes". -Christoffer