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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 7CA57C433B4 for ; Fri, 16 Apr 2021 11:40:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 547CD61184 for ; Fri, 16 Apr 2021 11:40:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242881AbhDPLlF (ORCPT ); Fri, 16 Apr 2021 07:41:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:46328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235422AbhDPLlD (ORCPT ); Fri, 16 Apr 2021 07:41:03 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 89260610F7; Fri, 16 Apr 2021 11:40:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618573239; bh=3OCC+s3KXL3CRYXcQVOMoxBoZGtDVHKh4WAw7RykLgQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pDOaH7UQSaGo/ZCEp5A6OFR9uKMDuK6uGnOs2vHTEXGRtAtsQKGjkGGsk3PWg0Rzz fg5+KAwrz0HnwaACc7tBFZJ0FiU+6QY7Mde5xF2bzgD5zKfq/0GkWvGZ39EIc0HE+g tlqJxhMX4svoPScIQ+NGKWutY1J3JP937aGi8BuabkOZ8RMt2ezysxFP/7zD0dNvZK XbxNl1K61A4bZMmOBWAoDp7p997vg1b6XUfa5J4Z770LWLkdcLFOcY1vZqHi2ZHjEw oeYfAwmsxCuYLBl5rTkg+43fXyLPqRl2huPLf6sA4MxYe08eveLy7DEAKMjqBLXamR eC3XO8P7cO9bw== Date: Fri, 16 Apr 2021 14:40:28 +0300 From: Mike Rapoport To: David Hildenbrand Cc: Anshuman Khandual , linux-arm-kernel@lists.infradead.org, Ard Biesheuvel , Catalin Marinas , Marc Zyngier , Mark Rutland , Mike Rapoport , Will Deacon , kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC/RFT PATCH 2/3] arm64: decouple check whether pfn is normal memory from pfn_valid() Message-ID: References: <20210407172607.8812-1-rppt@kernel.org> <20210407172607.8812-3-rppt@kernel.org> <4a788546-b854-fd35-644a-f1d9075a9a78@arm.com> <9c0956f0-494e-5c6b-bdc2-d4213afd5e2f@redhat.com> <62161846-4f03-e4b1-ae0b-fdf96f78d97c@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <62161846-4f03-e4b1-ae0b-fdf96f78d97c@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 15, 2021 at 11:31:26AM +0200, David Hildenbrand wrote: > On 14.04.21 22:29, Mike Rapoport wrote: > > On Wed, Apr 14, 2021 at 05:58:26PM +0200, David Hildenbrand wrote: > > > On 08.04.21 07:14, Anshuman Khandual wrote: > > > > > > > > On 4/7/21 10:56 PM, Mike Rapoport wrote: > > > > > From: Mike Rapoport > > > > > > > > > > The intended semantics of pfn_valid() is to verify whether there is a > > > > > struct page for the pfn in question and nothing else. > > > > > > > > Should there be a comment affirming this semantics interpretation, above the > > > > generic pfn_valid() in include/linux/mmzone.h ? > > > > > > > > > > > > > > Yet, on arm64 it is used to distinguish memory areas that are mapped in the > > > > > linear map vs those that require ioremap() to access them. > > > > > > > > > > Introduce a dedicated pfn_is_memory() to perform such check and use it > > > > > where appropriate. > > > > > > > > > > Signed-off-by: Mike Rapoport > > > > > --- > > > > > arch/arm64/include/asm/memory.h | 2 +- > > > > > arch/arm64/include/asm/page.h | 1 + > > > > > arch/arm64/kvm/mmu.c | 2 +- > > > > > arch/arm64/mm/init.c | 6 ++++++ > > > > > arch/arm64/mm/ioremap.c | 4 ++-- > > > > > arch/arm64/mm/mmu.c | 2 +- > > > > > 6 files changed, 12 insertions(+), 5 deletions(-) > > > > > > > > > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > > > > > index 0aabc3be9a75..7e77fdf71b9d 100644 > > > > > --- a/arch/arm64/include/asm/memory.h > > > > > +++ b/arch/arm64/include/asm/memory.h > > > > > @@ -351,7 +351,7 @@ static inline void *phys_to_virt(phys_addr_t x) > > > > > #define virt_addr_valid(addr) ({ \ > > > > > __typeof__(addr) __addr = __tag_reset(addr); \ > > > > > - __is_lm_address(__addr) && pfn_valid(virt_to_pfn(__addr)); \ > > > > > + __is_lm_address(__addr) && pfn_is_memory(virt_to_pfn(__addr)); \ > > > > > }) > > > > > void dump_mem_limit(void); > > > > > diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h > > > > > index 012cffc574e8..32b485bcc6ff 100644 > > > > > --- a/arch/arm64/include/asm/page.h > > > > > +++ b/arch/arm64/include/asm/page.h > > > > > @@ -38,6 +38,7 @@ void copy_highpage(struct page *to, struct page *from); > > > > > typedef struct page *pgtable_t; > > > > > extern int pfn_valid(unsigned long); > > > > > +extern int pfn_is_memory(unsigned long); > > > > > #include > > > > > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > > > > > index 8711894db8c2..ad2ea65a3937 100644 > > > > > --- a/arch/arm64/kvm/mmu.c > > > > > +++ b/arch/arm64/kvm/mmu.c > > > > > @@ -85,7 +85,7 @@ void kvm_flush_remote_tlbs(struct kvm *kvm) > > > > > static bool kvm_is_device_pfn(unsigned long pfn) > > > > > { > > > > > - return !pfn_valid(pfn); > > > > > + return !pfn_is_memory(pfn); > > > > > } > > > > > /* > > > > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > > > > > index 3685e12aba9b..258b1905ed4a 100644 > > > > > --- a/arch/arm64/mm/init.c > > > > > +++ b/arch/arm64/mm/init.c > > > > > @@ -258,6 +258,12 @@ int pfn_valid(unsigned long pfn) > > > > > } > > > > > EXPORT_SYMBOL(pfn_valid); > > > > > +int pfn_is_memory(unsigned long pfn) > > > > > +{ > > > > > + return memblock_is_map_memory(PFN_PHYS(pfn)); > > > > > +} > > > > > +EXPORT_SYMBOL(pfn_is_memory);> + > > > > > > > > Should not this be generic though ? There is nothing platform or arm64 > > > > specific in here. Wondering as pfn_is_memory() just indicates that the > > > > pfn is linear mapped, should not it be renamed as pfn_is_linear_memory() > > > > instead ? Regardless, it's fine either way. > > > > > > TBH, I dislike (generic) pfn_is_memory(). It feels like we're mixing > > > concepts. > > > > Yeah, at the moment NOMAP is very much arm specific so I'd keep it this way > > for now. > > > > > NOMAP memory vs !NOMAP memory; even NOMAP is some kind of memory > > > after all. pfn_is_map_memory() would be more expressive, although still > > > sub-optimal. > > > > > > We'd actually want some kind of arm64-specific pfn_is_system_memory() or the > > > inverse pfn_is_device_memory() -- to be improved. > > > > In my current version (to be posted soon) I've started with > > pfn_lineary_mapped() but then ended up with pfn_mapped() to make it > > "upward" compatible with architectures that use direct rather than linear > > map :) > > And even that is moot. It doesn't tell you if a PFN is *actually* mapped > (hello secretmem). > > I'd suggest to just use memblock_is_map_memory() in arch specific code. Then > it's clear what we are querying exactly and what the semantics might be. Ok, let's export memblock_is_map_memory() for the KEEP_MEMBLOCK case. -- Sincerely yours, Mike.