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. 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
