在 2018年05月21日 21:23, Tom Lendacky 写道: > On 5/20/2018 10:45 PM, lijiang wrote: >> 在 2018年05月17日 21:45, lijiang 写道: >>> 在 2018年05月15日 21:31, Tom Lendacky 写道: >>>> On 5/14/2018 8:51 PM, Lianbo Jiang wrote: >>>>> It is convenient to remap the old memory encrypted to the second kernel by >>>>> calling ioremap_encrypted(). >>>>> >>>>> When sme enabled on AMD server, we also need to support kdump. Because >>>>> the memory is encrypted in the first kernel, we will remap the old memory >>>>> encrypted to the second kernel(crash kernel), and sme is also enabled in >>>>> the second kernel, otherwise the old memory encrypted can not be decrypted. >>>>> Because simply changing the value of a C-bit on a page will not >>>>> automatically encrypt the existing contents of a page, and any data in the >>>>> page prior to the C-bit modification will become unintelligible. A page of >>>>> memory that is marked encrypted will be automatically decrypted when read >>>>> from DRAM and will be automatically encrypted when written to DRAM. >>>>> >>>>> For the kdump, it is necessary to distinguish whether the memory is >>>>> encrypted. Furthermore, we should also know which part of the memory is >>>>> encrypted or decrypted. We will appropriately remap the memory according >>>>> to the specific situation in order to tell cpu how to deal with the >>>>> data(encrypted or decrypted). For example, when sme enabled, if the old >>>>> memory is encrypted, we will remap the old memory in encrypted way, which >>>>> will automatically decrypt the old memory encrypted when we read those data >>>>> from the remapping address. >>>>> >>>>> ---------------------------------------------- >>>>> | first-kernel | second-kernel | kdump support | >>>>> | (mem_encrypt=on|off) | (yes|no) | >>>>> |--------------+---------------+---------------| >>>>> | on | on | yes | >>>>> | off | off | yes | >>>>> | on | off | no | >>>>> | off | on | no | >>>>> |______________|_______________|_______________| >>>>> >>>>> Test tools: >>>>> makedumpfile[v1.6.3]: https://github.com/LianboJ/makedumpfile >>>>> commit e1de103eca8f (A draft for kdump vmcore about AMD SME) >>>>> Author: Lianbo Jiang <lijiang@xxxxxxxxxx> >>>>> Date: Mon May 14 17:02:40 2018 +0800 >>>>> Note: This patch can only dump vmcore in the case of SME enabled. >>>>> >>>>> crash-7.2.1: https://github.com/crash-utility/crash.git >>>>> commit 1e1bd9c4c1be (Fix for the "bpf" command display on Linux 4.17-rc1) >>>>> Author: Dave Anderson <anderson@xxxxxxxxxx> >>>>> Date: Fri May 11 15:54:32 2018 -0400 >>>>> >>>>> Test environment: >>>>> HP ProLiant DL385Gen10 AMD EPYC 7251 >>>>> 8-Core Processor >>>>> 32768 MB memory >>>>> 600 GB disk space >>>>> >>>>> Linux 4.17-rc4: >>>>> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >>>>> commit 75bc37fefc44 ("Linux 4.17-rc4") >>>>> Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> >>>>> Date: Sun May 6 16:57:38 2018 -1000 >>>>> >>>>> Reference: >>>>> AMD64 Architecture Programmer's Manual >>>>> https://support.amd.com/TechDocs/24593.pdf >>>>> >>>> >>>> Have you also tested this with SEV? It would be nice if the kdump >>>> changes you make work with both SME and SEV. >>>> >>> Thank you, Tom. >>> This is a great question, we originally plan to implement SEV in subsequent patches, and >>> we are also working on SEV at present. >>> Furthermore, we have another known issue that the system can't jump into the second kernel >>> when SME is enabled and kaslr is disabled in kdump mode. It seems that is a complex problems, >>> maybe it is related to kaslr and SME, currently, i'm not sure the root cause, but we will >>> also plan to fix it. Can you give me any advice about this issue? >>> >> Based on upstream 4.17-rc5, we have recently found a new issue that the system can't boot to >> use kexec when SME is enabled and kaslr is disabled. Have you ever run into this issue? >> They have similar reproduction scenarios. >> >> CC Tom & Baoquan > > I haven't encountered this issue. Can you send the kernel config that you > are using? And your kernel command line? I'll try your config and see if > I can reproduce the issue. > Thank you, Tom. It doesn't have anything special config, and it's always reproduced. I will send another email to you about kernel config and command line. > Just to be clarify, you perform a power-on boot with SME enabled and KASLR > disabled (e.g. mem_encrypt=on nokaslr), correct, and that won't boot? > The system can boot in this case. Thanks. Lianbo > Thanks, > Tom > >> >> Thanks. >> Lianbo >> >>> Thanks. >>> Lianbo >>>> Thanks, >>>> Tom >>>> >>>>> Lianbo Jiang (2): >>>>> add a function(ioremap_encrypted) for kdump when AMD sme enabled. >>>>> support kdump when AMD secure memory encryption is active >>>>> >>>>> arch/x86/include/asm/dmi.h | 14 +++++++++++++- >>>>> arch/x86/include/asm/io.h | 2 ++ >>>>> arch/x86/kernel/acpi/boot.c | 8 ++++++++ >>>>> arch/x86/kernel/crash_dump_64.c | 27 +++++++++++++++++++++++++++ >>>>> arch/x86/mm/ioremap.c | 25 +++++++++++++++++-------- >>>>> drivers/acpi/tables.c | 14 +++++++++++++- >>>>> drivers/iommu/amd_iommu_init.c | 9 ++++++++- >>>>> fs/proc/vmcore.c | 36 +++++++++++++++++++++++++++++++----- >>>>> include/linux/crash_dump.h | 4 ++++ >>>>> kernel/kexec_core.c | 12 ++++++++++++ >>>>> 10 files changed, 135 insertions(+), 16 deletions(-) >>>>> _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
