Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754976Ab2HNIif (ORCPT ); Tue, 14 Aug 2012 04:38:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9662 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751684Ab2HNIic (ORCPT ); Tue, 14 Aug 2012 04:38:32 -0400 Message-ID: <502A0D9F.4010509@redhat.com> Date: Tue, 14 Aug 2012 16:34:39 +0800 From: Dave Young User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.22) Gecko/20110904 Red Hat/3.1.14-1.el6_1 Thunderbird/3.1.14 MIME-Version: 1.0 To: Jacob Shin CC: X86-ML , LKML , Yinghai Lu , "H. Peter Anvin" , Andreas Herrmann , Tejun Heo , Borislav Petkov , Chao Wang , Vivek Goyal Subject: Re: [PATCH V2 0/5] x86: Create direct mappings for E820_RAM only References: <1344894424-4434-1-git-send-email-jacob.shin@amd.com> In-Reply-To: <1344894424-4434-1-git-send-email-jacob.shin@amd.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5036 Lines: 123 On 08/14/2012 05:46 AM, Jacob Shin wrote: > Currently kernel direct mappings are created for all pfns between > [ 0 to max_low_pfn ) and [ 4GB to max_pfn ). When we introduce memory > holes, we end up mapping memory ranges that are not backed by physical > DRAM. This is fine for lower memory addresses which can be marked as UC > by fixed/variable range MTRRs, however we run in to trouble with high > addresses. > > The following patchset creates direct mappings only for E820_RAM regions > between 0 ~ max_low_pfn and 4GB ~ max_pfn. And leaves non-E820_RAM and > memory holes unmapped. Hi, Chaowang did some kdump test in a kvm guest with this patchset, 2nd kenrel just reboot after some ACPI printk, see below dmesg of 2nd kernel: After a crash: [snip] I'm in purgatory [ 0.000000] Initializing cgroup subsys cpuset [ 0.000000] Initializing cgroup subsys cpu [ 0.000000] Linux version 3.5.0-0.23.el7.bz846531.x86_64 (mockbuild@) (gcc version 4.7.1 20120720 (Red Hat 4.7.1-5) (GCC) ) #1 SMP Mon Aug 13 22:17:46 EDT 2012 [ 0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.5.0-0.23.el7.bz846531.x86_64 root=/dev/mapper/vg_none-lv_root ro rd.md=0 rd.lvm.lv=vg_none/lv_swap rd.dm=0 rd.lvm.lv=vg_none/lv_root rd.luks=0 LANG=en_US.UTF-8 console=ttyS0,115200 SYSFONT=True KEYTABLE=us earlyprintk=serial irqpoll nr_cpus=1 reset_devices cgroup_disable=memory mce=off earlyprintk=serial memmap=exactmap memmap=567K@64K memmap=261552K@589824K elfcorehdr=851376K [ 0.000000] e820: BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000100-0x000000000009dbff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009dc00-0x000000000009ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000003fffdfff] usable [ 0.000000] BIOS-e820: [mem 0x000000003fffe000-0x000000003fffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000feffc000-0x00000000feffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fffc0000-0x00000000ffffffff] reserved [ 0.000000] bootconsole [earlyser0] enabled [ 0.000000] ERROR: earlyprintk= earlyser already used [ 0.000000] e820: last_pfn = 0x3fffe max_arch_pfn = 0x400000000 [ 0.000000] NX (Execute Disable) protection: active [ 0.000000] e820: user-defined physical RAM map: [ 0.000000] user: [mem 0x0000000000010000-0x000000000009dbff] usable [ 0.000000] user: [mem 0x0000000024000000-0x0000000033f6bfff] usable [ 0.000000] DMI 2.4 present. [ 0.000000] No AGP bridge found [ 0.000000] e820: last_pfn = 0x33f6c max_arch_pfn = 0x400000000 [ 0.000000] PAT not supported by CPU. [ 0.000000] found SMP MP-table at [mem 0x000fdae0-0x000fdaef] mapped at [ffff8800000fdae0] [ 0.000000] init_memory_mapping: [mem 0x24000000-0x33f6bfff] [ 0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff] [ 0.000000] RAMDISK: [mem 0x3378a000-0x33f58fff] [ 0.000000] ACPI: RSDP 00000000000fd980 00014 (v00 BOCHS ) [ 0.000000] ACPI: RSDT 000000003fffe5b0 00038 (v01 BOCHS BXPCRSDT 00000001 BXPC 00000001) [ 0.000000] ACPI: FACP 000000003fffff80 00074 (v01 BOCHS BXPCFACP 00000001 BXPC 00000001) [ 0.000000] ACPI: DSDT 000000003fffe5f0 01121 (v01 BXPC BXDSDT 00000001 INTL 20100528) [ 0.000000] ACPI: FACS 000000003fffff40 00040 [ 0.000000] ACPI: SSDT 000000003ffffea0 0009E (v01 BOCHS BXPCSSDT 00000001 BXPC 00000001) [ 0.000000] ACPI: APIC 000000003ffffdb0 00078 (v01 BOCHS BXPCAPIC 00000001 BXPC 00000001) [ 0.000000] ACPI: HPET 000000003ffffd70 00038 (v01 BOCHS BXPCHPET 00000001 BXPC 00000001) [ 0.000000] ACPI: SSDT 000000003ffff720 00644 (v01 BXPC BXSSDTPC 00000001 INTL 20100528) ====2nd kernel reboot here===== > > This revision of the patchset attempts to resolve comments and concerns > from the following threads: > > https://lkml.org/lkml/2012/8/11/95 > > and > > https://lkml.org/lkml/2011/12/16/486 > > Jacob Shin (5): > x86: Only direct map addresses that are marked as E820_RAM > x86: find_early_table_space based on memory ranges that are being > mapped > x86: Keep track of direct mapped pfn ranges > x86: Fixup code testing if a pfn is direct mapped > x86: Move enabling of PSE and PGE out of init_memory_mapping > > arch/x86/include/asm/page_types.h | 9 +++ > arch/x86/kernel/amd_gart_64.c | 4 +- > arch/x86/kernel/cpu/amd.c | 6 +- > arch/x86/kernel/setup.c | 118 ++++++++++++++++++++++++++++++++----- > arch/x86/mm/init.c | 72 +++++++++++----------- > arch/x86/mm/init_64.c | 3 +- > arch/x86/platform/efi/efi.c | 8 +-- > arch/x86/platform/efi/efi_64.c | 2 + > 8 files changed, 157 insertions(+), 65 deletions(-) > -- Thanks Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/