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=-18.2 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,USER_AGENT_SANE_1 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 6636CC433B4 for ; Fri, 14 May 2021 23:51:24 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 1835861440 for ; Fri, 14 May 2021 23:51:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1835861440 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.127629.239890 (Exim 4.92) (envelope-from ) id 1lhhaN-00011x-6H; Fri, 14 May 2021 23:51:15 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 127629.239890; Fri, 14 May 2021 23:51:15 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lhhaN-00011q-2x; Fri, 14 May 2021 23:51:15 +0000 Received: by outflank-mailman (input) for mailman id 127629; Fri, 14 May 2021 23:51:13 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lhhaL-00011k-Rt for xen-devel@lists.xenproject.org; Fri, 14 May 2021 23:51:13 +0000 Received: from mail.kernel.org (unknown [198.145.29.99]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 38076f80-e871-4904-b875-bfd62736c1a3; Fri, 14 May 2021 23:51:13 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 033A261440; Fri, 14 May 2021 23:51:11 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 38076f80-e871-4904-b875-bfd62736c1a3 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621036272; bh=RkuxY7UFyW2YAXExWN195eVZmIgYm5uFRGdSYrW1fKc=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=l4jnYRa+mphpanBZnHu/qHfk0lts6053+TAWO9YtwOLj25UPd75UdaZWj5nEym/tY t6UmNpQ1/gB0Z4dFFzWQHxmSYCmQsAUne+hHwKeD+hIsoxazZ9W8L9p85XtH36BZ1I aF/bhAXKE4W0kXsTDY1wbYOenAL84+qq54DKKrtNu39vZVOYthi7TH7AyvVsWJjyWS GsPDi+Kkmc4bOpbRL7f7Le5Q92wx6JROL27/zx+TECiQf5vHOgh3YWr0At/GCT0ZXu ebpMmZc0giGGk0yhwOtpDAsro523n68KZEvAxwqtCFNmcxXtNUDkd5pZu5bnBAkNQf 4K/8kb/5yPKSQ== Date: Fri, 14 May 2021 16:51:11 -0700 (PDT) From: Stefano Stabellini X-X-Sender: sstabellini@sstabellini-ThinkPad-T480s To: Julien Grall cc: xen-devel@lists.xenproject.org, Wei.Chen@arm.com, Henry.Wang@arm.com, Penny.Zheng@arm.com, Bertrand.Marquis@arm.com, Julien Grall , Stefano Stabellini , Volodymyr Babchuk , Julien Grall Subject: Re: [PATCH RFCv2 14/15] xen/arm: mm: Rework setup_xenheap_mappings() In-Reply-To: <20210425201318.15447-15-julien@xen.org> Message-ID: References: <20210425201318.15447-1-julien@xen.org> <20210425201318.15447-15-julien@xen.org> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Sun, 25 Apr 2021, Julien Grall wrote: > From: Julien Grall > > A few issues have been reported with setup_xenheap_mappings() over the > last couple of years. The main ones are: > - It will break on platform supporting more than 512GB of RAM > because the memory allocated by the boot allocator is not yet > mapped. > - Aligning all the regions to 1GB may lead to unexpected result > because we may alias non-cacheable region (such as device or reserved > regions). > > map_pages_to_xen() was recently reworked to allow superpage mappings and > deal with the use of page-tables before they are mapped. > > Most of the code in setup_xenheap_mappings() is now replaced with a > single call to map_pages_to_xen(). > > This also require to re-order the steps setup_mm() so the regions are > given to the boot allocator first and then we setup the xenheap > mappings. I know this is paranoia but doesn't this introduce a requirement on the size of the first bank in bootinfo.mem.bank[] ? It should be at least 8KB? I know it is unlikely but it is theoretically possible to have a first bank of just 1KB. I think we should write the requirement down with an in-code comment? Or better maybe we should write a message about it in the panic below? > Note that the 1GB alignment is not yet removed. > > Signed-off-by: Julien Grall > Signed-off-by: Julien Grall > > --- > Changes in v2: > - New patch > > TODO: > - Remove the 1GB alignment > - Add support for setting the contiguous bit > --- > xen/arch/arm/mm.c | 60 ++++---------------------------------------- > xen/arch/arm/setup.c | 10 ++++++-- I love it! > 2 files changed, 13 insertions(+), 57 deletions(-) > > diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c > index f5768f2d4a81..c49403b687f5 100644 > --- a/xen/arch/arm/mm.c > +++ b/xen/arch/arm/mm.c > @@ -143,17 +143,6 @@ static DEFINE_PAGE_TABLE(cpu0_pgtable); > static DEFINE_PAGE_TABLES(cpu0_dommap, DOMHEAP_SECOND_PAGES); > #endif > > -#ifdef CONFIG_ARM_64 > -/* The first page of the first level mapping of the xenheap. The > - * subsequent xenheap first level pages are dynamically allocated, but > - * we need this one to bootstrap ourselves. */ > -static DEFINE_PAGE_TABLE(xenheap_first_first); > -/* The zeroeth level slot which uses xenheap_first_first. Used because > - * setup_xenheap_mappings otherwise relies on mfn_to_virt which isn't > - * valid for a non-xenheap mapping. */ > -static __initdata int xenheap_first_first_slot = -1; > -#endif > - > /* Common pagetable leaves */ > /* Second level page tables. > * > @@ -818,9 +807,9 @@ void __init setup_xenheap_mappings(unsigned long base_mfn, > void __init setup_xenheap_mappings(unsigned long base_mfn, > unsigned long nr_mfns) > { > - lpae_t *first, pte; > unsigned long mfn, end_mfn; > vaddr_t vaddr; > + int rc; > > /* Align to previous 1GB boundary */ > mfn = base_mfn & ~((FIRST_SIZE>>PAGE_SHIFT)-1); > @@ -846,49 +835,10 @@ void __init setup_xenheap_mappings(unsigned long base_mfn, > */ > vaddr = (vaddr_t)__mfn_to_virt(base_mfn) & FIRST_MASK; > > - while ( mfn < end_mfn ) > - { > - int slot = zeroeth_table_offset(vaddr); > - lpae_t *p = &xen_pgtable[slot]; > - > - if ( p->pt.valid ) > - { > - /* mfn_to_virt is not valid on the 1st 1st mfn, since it > - * is not within the xenheap. */ > - first = slot == xenheap_first_first_slot ? > - xenheap_first_first : mfn_to_virt(lpae_get_mfn(*p)); > - } > - else if ( xenheap_first_first_slot == -1) > - { > - /* Use xenheap_first_first to bootstrap the mappings */ > - first = xenheap_first_first; > - > - pte = pte_of_xenaddr((vaddr_t)xenheap_first_first); > - pte.pt.table = 1; > - write_pte(p, pte); > - > - xenheap_first_first_slot = slot; > - } > - else > - { > - mfn_t first_mfn = alloc_boot_pages(1, 1); > - > - clear_page(mfn_to_virt(first_mfn)); > - pte = mfn_to_xen_entry(first_mfn, MT_NORMAL); > - pte.pt.table = 1; > - write_pte(p, pte); > - first = mfn_to_virt(first_mfn); > - } > - > - pte = mfn_to_xen_entry(_mfn(mfn), MT_NORMAL); > - /* TODO: Set pte.pt.contig when appropriate. */ > - write_pte(&first[first_table_offset(vaddr)], pte); > - > - mfn += FIRST_SIZE>>PAGE_SHIFT; > - vaddr += FIRST_SIZE; > - } > - > - flush_xen_tlb_local(); > + rc = map_pages_to_xen(vaddr, _mfn(mfn), end_mfn - mfn, > + PAGE_HYPERVISOR_RW | _PAGE_BLOCK); > + if ( rc ) > + panic("Unable to setup the xenheap mappings.\n"); This is the panic I was talking about > } > #endif > > diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c > index 00aad1c194b9..0993a4bb52d4 100644 > --- a/xen/arch/arm/setup.c > +++ b/xen/arch/arm/setup.c > @@ -761,8 +761,11 @@ static void __init setup_mm(void) > ram_start = min(ram_start,bank_start); > ram_end = max(ram_end,bank_end); > > - setup_xenheap_mappings(bank_start>>PAGE_SHIFT, bank_size>>PAGE_SHIFT); > - > + /* > + * Add the region to the boot allocator first, so we can use > + * some to allocate page-tables for setting up the xenheap > + * mappings. > + */ > s = bank_start; > while ( s < bank_end ) > { > @@ -781,6 +784,9 @@ static void __init setup_mm(void) > fw_unreserved_regions(s, e, init_boot_pages, 0); > s = n; > } > + > + setup_xenheap_mappings(bank_start >> PAGE_SHIFT, > + bank_size >> PAGE_SHIFT); > } > > total_pages += ram_size >> PAGE_SHIFT; > -- > 2.17.1 >