From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932326Ab2HPQO3 (ORCPT ); Thu, 16 Aug 2012 12:14:29 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:21475 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757650Ab2HPQNV (ORCPT ); Thu, 16 Aug 2012 12:13:21 -0400 From: Konrad Rzeszutek Wilk To: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com Cc: Konrad Rzeszutek Wilk Subject: [PATCH 02/11] xen/x86: Use memblock_reserve for sensitive areas. Date: Thu, 16 Aug 2012 12:03:20 -0400 Message-Id: <1345133009-21941-3-git-send-email-konrad.wilk@oracle.com> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <1345133009-21941-1-git-send-email-konrad.wilk@oracle.com> References: <1345133009-21941-1-git-send-email-konrad.wilk@oracle.com> X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org instead of a big memblock_reserve. This way we can be more selective in freeing regions (and it also makes it easier to understand where is what). [v1: Move the auto_translate_physmap to proper line] [v2: Per Stefano suggestion add more comments] Signed-off-by: Konrad Rzeszutek Wilk --- arch/x86/xen/enlighten.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++ arch/x86/xen/p2m.c | 5 ++++ arch/x86/xen/setup.c | 9 -------- 3 files changed, 53 insertions(+), 9 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index ff962d4..e532eb5 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -998,7 +998,54 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) return ret; } +/* + * If the MFN is not in the m2p (provided to us by the hypervisor) this + * function won't do anything. In practice this means that the XenBus + * MFN won't be available for the initial domain. */ +static void __init xen_reserve_mfn(unsigned long mfn) +{ + unsigned long pfn; + + if (!mfn) + return; + pfn = mfn_to_pfn(mfn); + if (phys_to_machine_mapping_valid(pfn)) + memblock_reserve(PFN_PHYS(pfn), PAGE_SIZE); +} +static void __init xen_reserve_internals(void) +{ + unsigned long size; + + if (!xen_pv_domain()) + return; + + /* xen_start_info does not exist in the M2P, hence can't use + * xen_reserve_mfn. */ + memblock_reserve(__pa(xen_start_info), PAGE_SIZE); + + xen_reserve_mfn(PFN_DOWN(xen_start_info->shared_info)); + xen_reserve_mfn(xen_start_info->store_mfn); + if (!xen_initial_domain()) + xen_reserve_mfn(xen_start_info->console.domU.mfn); + + if (xen_feature(XENFEAT_auto_translated_physmap)) + return; + + /* + * ALIGN up to compensate for the p2m_page pointing to an array that + * can partially filled (look in xen_build_dynamic_phys_to_machine). + */ + + size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long)); + + /* We could use xen_reserve_mfn here, but would end up looping quite + * a lot (and call memblock_reserve for each PAGE), so lets just use + * the easy way and reserve it wholesale. */ + memblock_reserve(__pa(xen_start_info->mfn_list), size); + + /* The pagetables are reserved in mmu.c */ +} void xen_setup_shared_info(void) { if (!xen_feature(XENFEAT_auto_translated_physmap)) { @@ -1362,6 +1409,7 @@ asmlinkage void __init xen_start_kernel(void) xen_raw_console_write("mapping kernel into physical memory\n"); pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages); + xen_reserve_internals(); /* Allocate and initialize top and mid mfn levels for p2m structure */ xen_build_mfn_list_list(); diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index e4adbfb..6a2bfa4 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -388,6 +388,11 @@ void __init xen_build_dynamic_phys_to_machine(void) } m2p_override_init(); + + /* NOTE: We cannot call memblock_reserve here for the mfn_list as there + * isn't enough pieces to make it work (for one - we are still using the + * Xen provided pagetable). Do it later in xen_reserve_internals. + */ } unsigned long get_phys_to_machine(unsigned long pfn) diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index a4790bf..9efca75 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -424,15 +424,6 @@ char * __init xen_memory_setup(void) e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, E820_RESERVED); - /* - * Reserve Xen bits: - * - mfn_list - * - xen_start_info - * See comment above "struct start_info" in - */ - memblock_reserve(__pa(xen_start_info->mfn_list), - xen_start_info->pt_base - xen_start_info->mfn_list); - sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); return "Xen"; -- 1.7.7.6