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 X-Spam-Level: X-Spam-Status: No, score=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E40A0C433E0 for ; Tue, 16 Jun 2020 11:24:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0CA020734 for ; Tue, 16 Jun 2020 11:24:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="tUKMMmlm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725901AbgFPLYm (ORCPT ); Tue, 16 Jun 2020 07:24:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725843AbgFPLYl (ORCPT ); Tue, 16 Jun 2020 07:24:41 -0400 Received: from merlin.infradead.org (unknown [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 529AAC08C5C2; Tue, 16 Jun 2020 04:24:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=dx/XDzmerQqHyMbNLBn+Q6s8VjrBl9v+6BnDFssdgrQ=; b=tUKMMmlm3EnU2lxXAKbz3w9Qbs 59yhwU6FOtCCroQoFjW2uNXAffoPEwewaugQRiFECn4Go7fy5R9RyPsgm008fHygRH/vFPTiCnWM2 g06WevqHZ5+lFlV6Uk3TyBPWkeEV1JJ5r8rh4L+K4f0d+jB2gk6+L0eKldWP0tx+Ql8B8kSerMRkT qRTVHZ4xX2bVgF8m4F1mJ3VJOWV1KTZZGi1FrazYSZx0V2UkQPDpGcC3lohSD3ltpDcx0VebstcP2 Iz2Xx4sbeKvL0k2aimmLl0hEo112ZaNqWPH5w3lnpS+q+CUvxoFLPTQMpMGTnBrIspklKjAQx7j2S Y6fh647g==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jl9hS-0008PC-8L; Tue, 16 Jun 2020 11:24:18 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A8721306089; Tue, 16 Jun 2020 13:24:15 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 993442BECAD2D; Tue, 16 Jun 2020 13:24:15 +0200 (CEST) Date: Tue, 16 Jun 2020 13:24:15 +0200 From: Peter Zijlstra To: Christoph Hellwig Cc: Dexuan Cui , vkuznets , Stephen Hemminger , Andy Lutomirski , Andy Lutomirski , Michael Kelley , Ju-Hyoung Lee , "x86@kernel.org" , "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , KY Srinivasan , Tom Lendacky Subject: Re: hv_hypercall_pg page permissios Message-ID: <20200616112415.GT2531@hirez.programming.kicks-ass.net> References: <20200616072318.GA17600@lst.de> <20200616101807.GO2531@hirez.programming.kicks-ass.net> <20200616102350.GA29684@lst.de> <20200616102412.GB29684@lst.de> <20200616103137.GQ2531@hirez.programming.kicks-ass.net> <20200616103313.GA30833@lst.de> <20200616104032.GR2531@hirez.programming.kicks-ass.net> <20200616104230.GA31314@lst.de> <20200616105200.GA32175@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200616105200.GA32175@lst.de> Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Tue, Jun 16, 2020 at 12:52:00PM +0200, Christoph Hellwig wrote: > I think something like this should solve the issue: > > -- > diff --git a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h > index e988bac0a4a1c3..716e4de44a8e78 100644 > --- a/arch/x86/include/asm/module.h > +++ b/arch/x86/include/asm/module.h > @@ -13,4 +13,6 @@ struct mod_arch_specific { > #endif > }; > > +void *module_alloc_prot(unsigned long size, pgprot_t prot); > + > #endif /* _ASM_X86_MODULE_H */ > diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c > index 34b153cbd4acb4..4db6e655120960 100644 > --- a/arch/x86/kernel/module.c > +++ b/arch/x86/kernel/module.c > @@ -65,8 +65,10 @@ static unsigned long int get_module_load_offset(void) > } > #endif > > -void *module_alloc(unsigned long size) > +void *module_alloc_prot(unsigned long size, pgprot_t prot) > { > + unsigned int flags = (pgprot_val(prot) & _PAGE_NX) ? > + 0 : VM_FLUSH_RESET_PERMS; > void *p; > > if (PAGE_ALIGN(size) > MODULES_LEN) > @@ -75,7 +77,7 @@ void *module_alloc(unsigned long size) > p = __vmalloc_node_range(size, MODULE_ALIGN, > MODULES_VADDR + get_module_load_offset(), > MODULES_END, GFP_KERNEL, > - PAGE_KERNEL, 0, NUMA_NO_NODE, > + prot, flags, NUMA_NO_NODE, > __builtin_return_address(0)); > if (p && (kasan_module_alloc(p, size) < 0)) { > vfree(p); Hurmm.. Yes it would. It just doesn't feel right though. Can't we unconditionally set the flag? At worst it makes free a little bit more expensive. The thing is, I don't think _NX is the only prot that needs restoring. Any prot other than the default (RW IIRC) needs restoring.