On Mon, Aug 02, 2021 at 05:53:53PM -0400, Pavel Tatashin wrote:
> Changelog:
> v16:
>       - Merged with 5.14-rc4
> v15:
>       - Changed trans_pgd_copy_el2_vectors() to use vector table that
>         only shared by kexec and hibernate. This way sync does not have
>         dangling branch that was recently introduced. (Reported by Marc
>         Zyngier)
>       - Renamed is_hyp_callable() to is_hyp_nvhe() as requested by Marc
>         Zyngier
>       - Clean-ups, comment fixes.
>       - Sync with upstream 368094df48e680fa51cedb68537408cfa64b788e
> v14:
>       - Fixed a bug in "arm64: hyp-stub: Move elx_sync into the vectors"
>         that was noticed by Marc Zyngier
>       - Merged with upstream
> v13:
>       - Fixed a hang on ThunderX2, thank you Pingfan Liu for reporting
>         the problem. In relocation function we need civac not ivac, we
>         need to clean data in addition to invalidating it.
>         Since I was using ThunderX2 machine I also measured the new
>         performance data on this large ARM64 server. The MMU improves
>         kexec relocation 190 times on this machine! (see below for
>         raw data). Saves 7.5s during CentOS kexec reboot.
> v12:
>       - A major change compared to previous version. Instead of using
>         contiguous VA range a copy of linear map is now used to perform
>         copying of segments during relocation as it was agreed in the
>         discussion of version 11 of this project.
>       - In addition to using linear map, I also took several ideas from
>         James Morse to better organize the kexec relocation:
>               1. skip relocation function entirely if that is not needed
>               2. remove the PoC flushing function since it is not needed
>                  anymore with MMU enabled.
> v11:
>       - Fixed missing KEXEC_CORE dependency for trans_pgd.c
>       - Removed useless "if(rc) return rc" statement (thank you Tyler Hicks)
>       - Another 12 patches were accepted into maintainer's get.
>         Re-based patches against:
>         https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git
>         Branch: for-next/kexec
> v10:
>       - Addressed a lot of comments form James Morse and from  Marc Zyngier
>       - Added review-by's
>       - Synchronized with mainline
> 
> v9:   - 9 patches from previous series landed in upstream, so now series
>         is smaller
>       - Added two patches from James Morse to address idmap issues for 
> machines
>         with high physical addresses.
>       - Addressed comments from Selin Dag about compiling issues. He also 
> tested
>         my series and got similar performance results: ~60 ms instead of ~580 
> ms
>         with an initramfs size of ~120MB.
> v8:
>       - Synced with mainline to keep series up-to-date
> v7:
>       -- Addressed comments from James Morse
>       - arm64: hibernate: pass the allocated pgdp to ttbr0
>         Removed "Fixes" tag, and added Added Reviewed-by: James Morse
>       - arm64: hibernate: check pgd table allocation
>         Sent out as a standalone patch so it can be sent to stable
>         Series applies on mainline + this patch
>       - arm64: hibernate: add trans_pgd public functions
>         Remove second allocation of tmp_pg_dir in swsusp_arch_resume
>         Added Reviewed-by: James Morse <james.mo...@arm.com>
>       - arm64: kexec: move relocation function setup and clean up
>         Fixed typo in commit log
>         Changed kern_reloc to phys_addr_t types.
>         Added explanation why kern_reloc is needed.
>         Split into four patches:
>         arm64: kexec: make dtb_mem always enabled
>         arm64: kexec: remove unnecessary debug prints
>         arm64: kexec: call kexec_image_info only once
>         arm64: kexec: move relocation function setup
>       - arm64: kexec: add expandable argument to relocation function
>         Changed types of new arguments from unsigned long to phys_addr_t.
>         Changed offset prefix to KEXEC_*
>         Split into four patches:
>         arm64: kexec: cpu_soft_restart change argument types
>         arm64: kexec: arm64_relocate_new_kernel clean-ups
>         arm64: kexec: arm64_relocate_new_kernel don't use x0 as temp
>         arm64: kexec: add expandable argument to relocation function
>       - arm64: kexec: configure trans_pgd page table for kexec
>         Added invalid entries into EL2 vector table
>         Removed KEXEC_EL2_VECTOR_TABLE_SIZE and KEXEC_EL2_VECTOR_TABLE_OFFSET
>         Copy relocation functions and table into separate pages
>         Changed types in kern_reloc_arg.
>         Split into three patches:
>         arm64: kexec: offset for relocation function
>         arm64: kexec: kexec EL2 vectors
>         arm64: kexec: configure trans_pgd page table for kexec
>       - arm64: kexec: enable MMU during kexec relocation
>         Split into two patches:
>         arm64: kexec: enable MMU during kexec relocation
>         arm64: kexec: remove head from relocation argument
> v6:
>       - Sync with mainline tip
>       - Added Acked's from Dave Young
> v5:
>       - Addressed comments from Matthias Brugger: added review-by's, improved
>         comments, and made cleanups to swsusp_arch_resume() in addition to
>         create_safe_exec_page().
>       - Synced with mainline tip.
> v4:
>       - Addressed comments from James Morse.
>       - Split "check pgd table allocation" into two patches, and moved to
>         the beginning of series  for simpler backport of the fixes.
>         Added "Fixes:" tags to commit logs.
>       - Changed "arm64, hibernate:" to "arm64: hibernate:"
>       - Added Reviewed-by's
>       - Moved "add PUD_SECT_RDONLY" earlier in series to be with other
>         clean-ups
>       - Added "Derived from:" to arch/arm64/mm/trans_pgd.c
>       - Removed "flags" from trans_info
>       - Changed .trans_alloc_page assumption to return zeroed page.
>       - Simplify changes to trans_pgd_map_page(), by keeping the old
>         code.
>       - Simplify changes to trans_pgd_create_copy, by keeping the old
>         code.
>       - Removed: "add trans_pgd_create_empty"
>       - replace init_mm with NULL, and keep using non "__" version of
>         populate functions.
> v3:
>       - Split changes to create_safe_exec_page() into several patches for
>         easier review as request by Mark Rutland. This is why this series
>         has 3 more patches.
>       - Renamed trans_table to tans_pgd as agreed with Mark. The header
>         comment in trans_pgd.c explains that trans stands for
>         transitional page tables. Meaning they are used in transition
>         between two kernels.
> v2:
>       - Fixed hibernate bug reported by James Morse
>       - Addressed comments from James Morse:
>         * More incremental changes to trans_table
>         * Removed TRANS_FORCEMAP
>         * Added kexec reboot data for image with 380M in size.
> 
> Enable MMU during kexec relocation in order to improve reboot performance.
> 
> If kexec functionality is used for a fast system update, with a minimal
> downtime, the relocation of kernel + initramfs takes a significant portion
> of reboot.
> 
> The reason for slow relocation is because it is done without MMU, and thus
> not benefiting from D-Cache.
> 
> Performance data
> ----------------
> 
> Cavium ThunderX2:
> Kernel Image size: 38M Iniramfs size: 46M Total relocation size: 84M
> MMU-disabled:
> relocation    7.489539915s
> MMU-enabled:
> relocation    0.03946095s
> 
> Relocation performance is improved 190 times.
> 
> Broadcom Stingray:
> For this experiment, the size of kernel plus initramfs is small, only 25M.
> If initramfs was larger, than the improvements would be greater, as time
> spent in relocation is proportional to the size of relocation.
> 
> MMU-disabled::
> kernel shutdown       0.022131328s
> relocation    0.440510736s
> kernel startup        0.294706768s
> 
> Relocation was taking: 58.2% of reboot time
> 
> MMU-enabled:
> kernel shutdown       0.032066576s
> relocation    0.022158152s
> kernel startup        0.296055880s
> 
> Now: Relocation takes 6.3% of reboot time
> 
> Total reboot is x2.16 times faster.
> 
> With bigger userland (fitImage 380M), the reboot time is improved by 3.57s,
> and is reduced from 3.9s down to 0.33s
> 
> Previous approaches and discussions
> -----------------------------------
> v15: 
> https://lore.kernel.org/lkml/20210609004419.936873-1-pasha.tatas...@soleen.com
> v14: 
> https://lore.kernel.org/lkml/20210527150526.271941-1-pasha.tatas...@soleen.com
> v13: 
> https://lore.kernel.org/lkml/20210408040537.2703241-1-pasha.tatas...@soleen.com
> v12: 
> https://lore.kernel.org/lkml/20210303002230.1083176-1-pasha.tatas...@soleen.com
> v11: 
> https://lore.kernel.org/lkml/20210127172706.617195-1-pasha.tatas...@soleen.com
> v10: 
> https://lore.kernel.org/linux-arm-kernel/20210125191923.1060122-1-pasha.tatas...@soleen.com
> v9: 
> https://lore.kernel.org/lkml/20200326032420.27220-1-pasha.tatas...@soleen.com
> v8: 
> https://lore.kernel.org/lkml/20191204155938.2279686-1-pasha.tatas...@soleen.com
> v7: 
> https://lore.kernel.org/lkml/20191016200034.1342308-1-pasha.tatas...@soleen.com
> v6: 
> https://lore.kernel.org/lkml/20191004185234.31471-1-pasha.tatas...@soleen.com
> v5: 
> https://lore.kernel.org/lkml/20190923203427.294286-1-pasha.tatas...@soleen.com
> v4: 
> https://lore.kernel.org/lkml/20190909181221.309510-1-pasha.tatas...@soleen.com
> v3: 
> https://lore.kernel.org/lkml/20190821183204.23576-1-pasha.tatas...@soleen.com
> v2: 
> https://lore.kernel.org/lkml/20190817024629.26611-1-pasha.tatas...@soleen.com
> v1: 
> https://lore.kernel.org/lkml/20190801152439.11363-1-pasha.tatas...@soleen.com
> 
> Pavel Tatashin (15):
>   arm64: kernel: add helper for booted at EL2 and not VHE
>   arm64: trans_pgd: hibernate: Add trans_pgd_copy_el2_vectors
>   arm64: hibernate: abstract ttrb0 setup function
>   arm64: kexec: flush image and lists during kexec load time
>   arm64: kexec: skip relocation code for inplace kexec
>   arm64: kexec: Use dcache ops macros instead of open-coding
>   arm64: kexec: pass kimage as the only argument to relocation function
>   arm64: kexec: configure EL2 vectors for kexec
>   arm64: kexec: relocate in EL1 mode
>   arm64: kexec: use ld script for relocation function
>   arm64: kexec: install a copy of the linear-map
>   arm64: kexec: keep MMU enabled during kexec relocation
>   arm64: kexec: remove the pre-kexec PoC maintenance
>   arm64: kexec: remove cpu-reset.h
>   arm64: trans_pgd: remove trans_pgd_map_page()
> 
>  arch/arm64/Kconfig                   |   2 +-
>  arch/arm64/include/asm/assembler.h   |  49 ++++++--
>  arch/arm64/include/asm/kexec.h       |  12 ++
>  arch/arm64/include/asm/mmu_context.h |  24 ++++
>  arch/arm64/include/asm/sections.h    |   1 +
>  arch/arm64/include/asm/trans_pgd.h   |  12 +-
>  arch/arm64/include/asm/virt.h        |   7 ++
>  arch/arm64/kernel/asm-offsets.c      |  11 ++
>  arch/arm64/kernel/cpu-reset.S        |   7 +-
>  arch/arm64/kernel/cpu-reset.h        |  32 -----
>  arch/arm64/kernel/hibernate-asm.S    |  72 -----------
>  arch/arm64/kernel/hibernate.c        |  49 ++------
>  arch/arm64/kernel/machine_kexec.c    | 177 ++++++++++++++-------------
>  arch/arm64/kernel/relocate_kernel.S  |  70 +++++------
>  arch/arm64/kernel/sdei.c             |   2 +-
>  arch/arm64/kernel/vmlinux.lds.S      |  19 +++
>  arch/arm64/mm/Makefile               |   1 +
>  arch/arm64/mm/trans_pgd-asm.S        |  65 ++++++++++
>  arch/arm64/mm/trans_pgd.c            |  82 ++++---------
>  19 files changed, 356 insertions(+), 338 deletions(-)
>  delete mode 100644 arch/arm64/kernel/cpu-reset.h
>  create mode 100644 arch/arm64/mm/trans_pgd-asm.S
> 
> 
> base-commit: c500bee1c5b2f1d59b1081ac879d73268ab0ff17
> -- 

Tested-by: Pingfan Liu <pi...@redhat.com>


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