Re: [PATCHv9 00/17] x86/tdx: Add kexec support

["Kalra, Ashish" <ashish.kalra@amd.com>]

Hi Kirill,

On 3/25/2024 5:38 AM, Kirill A. Shutemov wrote:
> The patchset adds bits and pieces to get kexec (and crashkernel) work on
> TDX guest.
>
> The last patch implements CPU offlining according to the approved ACPI
> spec change poposal[1]. It unlocks kexec with all CPUs visible in the target
> kernel. It requires BIOS-side enabling. If it missing we fallback to booting
> 2nd kernel with single CPU.
>
> Please review. I would be glad for any feedback.
>
> [1] https://lore.kernel.org/all/13356251.uLZWGnKmhe@kreacher
>
> v9:
>    - Rebased;
>    - Keep page tables that maps E820_TYPE_ACPI (Ashish);
>    - Ack/Reviewed/Tested-bys from Sathya, Kai, Tao;
>    - Minor printk() message adjustments;
> v8:
>    - Rework serialization of around conversion memory back to private;
>    - Print ACPI_MADT_TYPE_MULTIPROC_WAKEUP in acpi_table_print_madt_entry();
>    - Drop debugfs interface to dump info on shared memory;
>    - Adjust comments and commit messages;
>    - Reviewed-bys by Baoquan, Dave and Thomas;
> v7:
>    - Call enc_kexec_stop_conversion() and enc_kexec_unshare_mem() after shutting
>      down IO-APIC, lapic and hpet. It meets AMD requirements.
>    - Minor style changes;
>    - Add Acked/Reviewed-bys;
> v6:
>    - Rebased to v6.8-rc1;
>    - Provide default noop callbacks from .enc_kexec_stop_conversion and
>      .enc_kexec_unshare_mem;
>    - Split off patch that introduces .enc_kexec_* callbacks;
>    - asm_acpi_mp_play_dead(): program CR3 directly from RSI, no MOV to RAX
>      required;
>    - Restructure how smp_ops.stop_this_cpu() hooked up in crash_nmi_callback();
>    - kvmclock patch got merged via KVM tree;
> v5:
>    - Rename smp_ops.crash_play_dead to smp_ops.stop_this_cpu and use it in
>      stop_this_cpu();
>    - Split off enc_kexec_stop_conversion() from enc_kexec_unshare_mem();
>    - Introduce kernel_ident_mapping_free();
>    - Add explicit include for alternatives and stringify.
>    - Add barrier() after setting conversion_allowed to false;
>    - Mark cpu_hotplug_offline_disabled __ro_after_init;
>    - Print error if failed to hand over CPU to BIOS;
>    - Update comments and commit messages;
> v4:
>    - Fix build for !KEXEC_CORE;
>    - Cleaner ATLERNATIVE use;
>    - Update commit messages and comments;
>    - Add Reviewed-bys;
> v3:
>    - Rework acpi_mp_crash_stop_other_cpus() to avoid invoking hotplug state
>      machine;
>    - Free page tables if reset vector setup failed;
>    - Change asm_acpi_mp_play_dead() to pass reset vector and PGD as arguments;
>    - Mark acpi_mp_* variables as static and __ro_after_init;
>    - Use u32 for apicid;
>    - Disable CPU offlining if reset vector setup failed;
>    - Rename madt.S -> madt_playdead.S;
>    - Mark tdx_kexec_unshare_mem() as static;
>    - Rebase onto up-to-date tip/master;
>    - Whitespace fixes;
>    - Reorder patches;
>    - Add Reviewed-bys;
>    - Update comments and commit messages;
> v2:
>    - Rework how unsharing hook ups into kexec codepath;
>    - Rework kvmclock_disable() fix based on Sean's;
>    - s/cpu_hotplug_not_supported()/cpu_hotplug_disable_offlining()/;
>    - use play_dead_common() to implement acpi_mp_play_dead();
>    - cond_resched() in tdx_shared_memory_show();
>    - s/target kernel/second kernel/;
>    - Update commit messages and comments;
>
> Kirill A. Shutemov (17):
>    x86/acpi: Extract ACPI MADT wakeup code into a separate file
>    x86/apic: Mark acpi_mp_wake_* variables as __ro_after_init
>    cpu/hotplug: Add support for declaring CPU offlining not supported
>    cpu/hotplug, x86/acpi: Disable CPU offlining for ACPI MADT wakeup
>    x86/kexec: Keep CR4.MCE set during kexec for TDX guest
>    x86/mm: Make x86_platform.guest.enc_status_change_*() return errno
>    x86/mm: Return correct level from lookup_address() if pte is none
>    x86/tdx: Account shared memory
>    x86/mm: Adding callbacks to prepare encrypted memory for kexec
>    x86/tdx: Convert shared memory back to private on kexec
>    x86/mm: Make e820_end_ram_pfn() cover E820_TYPE_ACPI ranges
>    x86/acpi: Rename fields in acpi_madt_multiproc_wakeup structure
>    x86/acpi: Do not attempt to bring up secondary CPUs in kexec case
>    x86/smp: Add smp_ops.stop_this_cpu() callback
>    x86/mm: Introduce kernel_ident_mapping_free()
>    x86/acpi: Add support for CPU offlining for ACPI MADT wakeup method
>    ACPI: tables: Print MULTIPROC_WAKEUP when MADT is parsed
>
>   arch/x86/Kconfig                     |   7 +
>   arch/x86/coco/core.c                 |   1 -
>   arch/x86/coco/tdx/tdx.c              |  99 ++++++++-
>   arch/x86/hyperv/ivm.c                |   9 +-
>   arch/x86/include/asm/acpi.h          |   7 +
>   arch/x86/include/asm/init.h          |   3 +
>   arch/x86/include/asm/pgtable.h       |   5 +
>   arch/x86/include/asm/pgtable_types.h |   1 +
>   arch/x86/include/asm/set_memory.h    |   3 +
>   arch/x86/include/asm/smp.h           |   1 +
>   arch/x86/include/asm/x86_init.h      |   6 +-
>   arch/x86/kernel/acpi/Makefile        |  11 +-
>   arch/x86/kernel/acpi/boot.c          |  86 +-------
>   arch/x86/kernel/acpi/madt_playdead.S |  28 +++
>   arch/x86/kernel/acpi/madt_wakeup.c   | 292 +++++++++++++++++++++++++++
>   arch/x86/kernel/crash.c              |   6 +
>   arch/x86/kernel/e820.c               |   9 +-
>   arch/x86/kernel/process.c            |   7 +
>   arch/x86/kernel/reboot.c             |  18 ++
>   arch/x86/kernel/relocate_kernel_64.S |   5 +
>   arch/x86/kernel/x86_init.c           |   8 +-
>   arch/x86/mm/ident_map.c              |  73 +++++++
>   arch/x86/mm/mem_encrypt_amd.c        |   8 +-
>   arch/x86/mm/pat/set_memory.c         |  59 ++++--
>   drivers/acpi/tables.c                |  14 ++
>   include/acpi/actbl2.h                |  19 +-
>   include/linux/cc_platform.h          |  10 -
>   include/linux/cpu.h                  |   2 +
>   kernel/cpu.c                         |  12 +-
>   29 files changed, 663 insertions(+), 146 deletions(-)
>   create mode 100644 arch/x86/kernel/acpi/madt_playdead.S
>   create mode 100644 arch/x86/kernel/acpi/madt_wakeup.c

The cover letter mention the inclusion of the following patch - Keep 
page tables that maps E820_TYPE_ACPI (Ashish)

But i don't this patch included in your patch-set.

Thanks, Ashish