From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752041AbbFELL0 (ORCPT ); Fri, 5 Jun 2015 07:11:26 -0400 Received: from mail.skyhub.de ([78.46.96.112]:47003 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751376AbbFELLY (ORCPT ); Fri, 5 Jun 2015 07:11:24 -0400 Date: Fri, 5 Jun 2015 13:11:22 +0200 From: Borislav Petkov To: Ingo Molnar Cc: "H. Peter Anvin" , linux-tip-commits@vger.kernel.org, tip-bot for Andy Lutomirski , peterz@infradead.org, torvalds@linux-foundation.org, luto@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, akpm@linux-foundation.org Subject: Re: [tip:x86/asm] x86/asm/msr: Make wrmsrl_safe() a function Message-ID: <20150605111121.GA25351@pd.tnic> References: <20150605100442.GA8995@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20150605100442.GA8995@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 05, 2015 at 12:04:42PM +0200, Ingo Molnar wrote: > Yeah, so what I think should be done instead is to flip around the API: > make wrmsrl_safe() the primary API and derive wrmsr_safe() from that, > because it's the saner API and because we have 3 times more wrmsrl_safe() > users right now! > > And I'd make _that_ mapping inline, which would catch crap like: > > ./arch/x86/include/asm/msr.h: return wrmsr_safe(msr, (u32)val, (u32)(val >> 32)); > ./arch/x86/xen/enlighten.c: wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32)); > > and would turn it back into wrmsrl_safe(pfn)/etc. seemlessly. > > In addition to that we might even phase out the high/low API altogether, as code > like this: > > !wrmsr_safe(MSR_EFER, > header->pmode_efer_low, > header->pmode_efer_high)) > > should probably use a single u64. There's also msr_read()/msr_write() in arch/x86/lib/msr.c. They're not that straight-forward to use due to that struct msr thing as the second arg but we could wrap the creation of that thing in a higher-level caller. The advantage is that you can set both low, high and the whole u64 values directly and got the error handling of the safe variants. > But crappy paravirt indirections get in the way of an easy, trivial > restructuring, as usual... Tell me about it. :/ -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --