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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 C2AA4C3F2D7 for ; Mon, 2 Mar 2020 18:57:32 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7EFE720848 for ; Mon, 2 Mar 2020 18:57:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7EFE720848 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deltatee.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48WTsk0HLqzDqdp for ; Tue, 3 Mar 2020 05:57:30 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=deltatee.com (client-ip=207.54.116.67; helo=ale.deltatee.com; envelope-from=logang@deltatee.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=deltatee.com Received: from ale.deltatee.com (ale.deltatee.com [207.54.116.67]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48WTqV5hHZzDqcR for ; Tue, 3 Mar 2020 05:55:34 +1100 (AEDT) Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.92) (envelope-from ) id 1j8qDo-0005xH-8O; Mon, 02 Mar 2020 11:55:21 -0700 To: Dan Williams References: <20200221182503.28317-1-logang@deltatee.com> <20200221182503.28317-7-logang@deltatee.com> From: Logan Gunthorpe Message-ID: <8b13f6aa-77b7-a47d-1a49-b8e2f800ac9d@deltatee.com> Date: Mon, 2 Mar 2020 11:55:18 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: mhocko@suse.com, ebadger@gigaio.com, peterz@infradead.org, luto@kernel.org, dave.hansen@linux.intel.com, bp@alien8.de, mingo@redhat.com, tglx@linutronix.de, benh@kernel.crashing.org, will@kernel.org, catalin.marinas@arm.com, hch@lst.de, akpm@linux-foundation.org, david@redhat.com, mhocko@kernel.org, linux-mm@kvack.org, platform-driver-x86@vger.kernel.org, linux-sh@vger.kernel.org, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-ia64@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, dan.j.williams@intel.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v3 6/7] mm/memory_hotplug: Add pgprot_t to mhp_params X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Michal Hocko , linux-ia64@vger.kernel.org, Linux-sh , Peter Zijlstra , Catalin Marinas , Dave Hansen , platform-driver-x86@vger.kernel.org, Linux MM , Will Deacon , Christoph Hellwig , linux-s390 , David Hildenbrand , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , Michal Hocko , Linux ARM , Eric Badger , Linux Kernel Mailing List , Andrew Morton , linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 2020-02-29 3:44 p.m., Dan Williams wrote: > On Fri, Feb 21, 2020 at 10:25 AM Logan Gunthorpe wrote: >> >> devm_memremap_pages() is currently used by the PCI P2PDMA code to create >> struct page mappings for IO memory. At present, these mappings are created >> with PAGE_KERNEL which implies setting the PAT bits to be WB. However, on >> x86, an mtrr register will typically override this and force the cache >> type to be UC-. In the case firmware doesn't set this register it is >> effectively WB and will typically result in a machine check exception >> when it's accessed. >> >> Other arches are not currently likely to function correctly seeing they >> don't have any MTRR registers to fall back on. >> >> To solve this, provide a way to specify the pgprot value explicitly to >> arch_add_memory(). >> >> Of the arches that support MEMORY_HOTPLUG: x86_64, and arm64 need a simple >> change to pass the pgprot_t down to their respective functions which set >> up the page tables. For x86_32, set the page tables explicitly using >> _set_memory_prot() (seeing they are already mapped). For ia64, s390 and >> sh, reject anything but PAGE_KERNEL settings -- this should be fine, >> for now, seeing these architectures don't support ZONE_DEVICE. >> >> A check in __add_pages() is also added to ensure the pgprot parameter was >> set for all arches. >> >> Cc: Dan Williams >> Signed-off-by: Logan Gunthorpe >> Acked-by: David Hildenbrand >> Acked-by: Michal Hocko >> --- >> arch/arm64/mm/mmu.c | 3 ++- >> arch/ia64/mm/init.c | 3 +++ >> arch/powerpc/mm/mem.c | 3 ++- >> arch/s390/mm/init.c | 3 +++ >> arch/sh/mm/init.c | 3 +++ >> arch/x86/mm/init_32.c | 5 +++++ >> arch/x86/mm/init_64.c | 2 +- >> include/linux/memory_hotplug.h | 2 ++ >> mm/memory_hotplug.c | 5 ++++- >> mm/memremap.c | 6 +++--- >> 10 files changed, 28 insertions(+), 7 deletions(-) >> >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index ee37bca8aba8..ea3fa844a8a2 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -1058,7 +1058,8 @@ int arch_add_memory(int nid, u64 start, u64 size, >> flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; >> >> __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), >> - size, PAGE_KERNEL, __pgd_pgtable_alloc, flags); >> + size, params->pgprot, __pgd_pgtable_alloc, >> + flags); >> >> memblock_clear_nomap(start, size); >> >> diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c >> index 97bbc23ea1e3..d637b4ea3147 100644 >> --- a/arch/ia64/mm/init.c >> +++ b/arch/ia64/mm/init.c >> @@ -676,6 +676,9 @@ int arch_add_memory(int nid, u64 start, u64 size, >> unsigned long nr_pages = size >> PAGE_SHIFT; >> int ret; >> >> + if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot)) >> + return -EINVAL; >> + >> ret = __add_pages(nid, start_pfn, nr_pages, params); >> if (ret) >> printk("%s: Problem encountered in __add_pages() as ret=%d\n", >> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c >> index 19b1da5d7eca..832412bc7fad 100644 >> --- a/arch/powerpc/mm/mem.c >> +++ b/arch/powerpc/mm/mem.c >> @@ -138,7 +138,8 @@ int __ref arch_add_memory(int nid, u64 start, u64 size, >> resize_hpt_for_hotplug(memblock_phys_mem_size()); >> >> start = (unsigned long)__va(start); >> - rc = create_section_mapping(start, start + size, nid, PAGE_KERNEL); >> + rc = create_section_mapping(start, start + size, nid, >> + params->pgprot); >> if (rc) { >> pr_warn("Unable to create mapping for hot added memory 0x%llx..0x%llx: %d\n", >> start, start + size, rc); >> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c >> index e9e4a7abd0cc..87b2d024e75a 100644 >> --- a/arch/s390/mm/init.c >> +++ b/arch/s390/mm/init.c >> @@ -277,6 +277,9 @@ int arch_add_memory(int nid, u64 start, u64 size, >> if (WARN_ON_ONCE(params->altmap)) >> return -EINVAL; >> >> + if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot)) >> + return -EINVAL; >> + >> rc = vmem_add_mapping(start, size); >> if (rc) >> return rc; >> diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c >> index e5114c053364..b9de2d4fa57e 100644 >> --- a/arch/sh/mm/init.c >> +++ b/arch/sh/mm/init.c >> @@ -412,6 +412,9 @@ int arch_add_memory(int nid, u64 start, u64 size, >> unsigned long nr_pages = size >> PAGE_SHIFT; >> int ret; >> >> + if (WARN_ON_ONCE(params->pgprot.pgprot != PAGE_KERNEL.pgprot) >> + return -EINVAL; >> + >> /* We only have ZONE_NORMAL, so this is easy.. */ >> ret = __add_pages(nid, start_pfn, nr_pages, params); >> if (unlikely(ret)) >> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c >> index e25a4218e6ff..96d8e4fb1cc8 100644 >> --- a/arch/x86/mm/init_32.c >> +++ b/arch/x86/mm/init_32.c >> @@ -858,6 +858,11 @@ int arch_add_memory(int nid, u64 start, u64 size, >> { >> unsigned long start_pfn = start >> PAGE_SHIFT; >> unsigned long nr_pages = size >> PAGE_SHIFT; >> + int ret; >> + >> + ret = _set_memory_prot(start, nr_pages, params->pgprot); > > Perhaps a comment since it's not immediately obvious where the > PAGE_KERNEL prot was established, and perhaps add a conditional to > skip this call in the param->pgprot == PAGE_KERNEL case? Yes I can add the skip in the PAGE_KERNEL case. Though I'm not sure what you are asking for with regards to the comment. Just that pgprot is set by the caller usually to PAGE_KERNEL? > Other than that looks good to me, but only an ack since I'm only > testing the x86 changes. > > Acked-by: Dan Williams Thanks, Logan