[v17,0/8] Parallel CPU bringup for x86_64

  This version changes the number of cpuhp_states reserved for parallel bringup
from 4 (CPUHP_BP_PARALLEL_DYN to CPUHP_BP_PARALLEL_DYN_END) to 1
CPUHP_BP_PARALLEL_STARTUP.

Thanks,
Usama

Changes across versions:
v2: Cut it back to just INIT/SIPI/SIPI in parallel for now, nothing more
v3: Clean up x2apic patch, add MTRR optimisation, lock topology update
    in preparation for more parallelisation.
v4: Fixes to the real mode parallelisation patch spotted by SeanC, to
    avoid scribbling on initial_gs in common_cpu_up(), and to allow all
    24 bits of the physical X2APIC ID to be used. That patch still needs
    a Signed-off-by from its original author, who once claimed not to
    remember writing it at all. But now we've fixed it, hopefully he'll
    admit it now :)
v5: rebase to v6.1 and remeasure performance, disable parallel bringup
    for AMD CPUs.
v6: rebase to v6.2-rc6, disabled parallel boot on amd as a cpu bug and
    reused timer calibration for secondary CPUs.
v7: [David Woodhouse] iterate over all possible CPUs to find any existing
    cluster mask in alloc_clustermask. (patch 1/9)
    Keep parallel AMD support enabled in AMD, using APIC ID in CPUID leaf
    0x0B (for x2APIC mode) or CPUID leaf 0x01 where 8 bits are sufficient.
    Included sanity checks for APIC id from 0x0B. (patch 6/9)
    Removed patch for reusing timer calibration for secondary CPUs.
    commit message and code improvements.
v8: Fix CPU0 hotplug by setting up the initial_gs, initial_stack and
    early_gdt_descr.
    Drop trampoline lock and bail if APIC ID not found in find_cpunr.
    Code comments improved and debug prints added.
v9: Drop patch to avoid repeated saves of MTRR at boot time.
    rebased and retested at v6.2-rc8.
    added kernel doc for no_parallel_bringup and made do_parallel_bringup
    __ro_after_init.
v10: Fixed suspend/resume not working with parallel smpboot.
     rebased and retested to 6.2.
     fixed checkpatch errors.
v11: Added patches from Brian Gerst to remove the global variables initial_gs,
     initial_stack, and early_gdt_descr from the 64-bit boot code
     (https://lore.kernel.org/all/20230222221301.245890-1-brgerst@gmail.com/).
v12: Fixed compilation errors, acquire tr_lock for every stack setup in
     trampoline_64.S.
     Rearranged commits for a cleaner git history.
v13: Fix build error with CONFIG_FORCE_NR_CPUS.
     Commit message improved, typos fixed and extra comments added.
v14: Enable parallel bringup for SEV-ES guests.
v15: use vendor parallel_smp when platform has CC_ATTR_GUEST_STATE_ENCRYPT.
     Call smpboot_restore_warm_reset_vector incase any of the steps in
     native_cpu_up fail.
     Reset stale stack and kasan unpoison in bringup_cpu
     Release trampoline_lock a bit earlier.
v16: Roll back to CPUHP_OFFLINE on failure in parallel bringup case.
     Release trampoline_lock earlier, just before setup_gdt.
     Rebase to x86/apic (Linux 6.3-rc3).
v17: Change number of states for parallel bringup to one.

David Woodhouse (8):
  cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h>
  cpu/hotplug: Reset task stack state in _cpu_up()
  cpu/hotplug: Add CPUHP_BP_PARALLEL_STARTUP state before
    CPUHP_BRINGUP_CPU
  x86/smpboot: Split up native_cpu_up into separate phases and document
    them
  x86/smpboot: Support parallel startup of secondary CPUs
  x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel
  x86/smpboot: Serialize topology updates for secondary bringup
  x86/smpboot: Allow parallel bringup for SEV-ES

 .../admin-guide/kernel-parameters.txt         |   3 +
 arch/x86/coco/core.c                          |   5 +
 arch/x86/include/asm/coco.h                   |   1 +
 arch/x86/include/asm/cpu.h                    |   1 +
 arch/x86/include/asm/realmode.h               |   3 +
 arch/x86/include/asm/sev-common.h             |   3 +
 arch/x86/include/asm/smp.h                    |  13 +-
 arch/x86/include/asm/topology.h               |   2 -
 arch/x86/kernel/acpi/sleep.c                  |   9 +-
 arch/x86/kernel/apic/apic.c                   |   2 +-
 arch/x86/kernel/cpu/common.c                  |   6 +-
 arch/x86/kernel/cpu/topology.c                |   3 +-
 arch/x86/kernel/head_64.S                     |  97 +++++
 arch/x86/kernel/smpboot.c                     | 345 +++++++++++++-----
 arch/x86/realmode/init.c                      |   3 +
 arch/x86/realmode/rm/trampoline_64.S          |  27 +-
 arch/x86/xen/smp_pv.c                         |   4 +-
 include/linux/cpuhotplug.h                    |  22 ++
 include/linux/smpboot.h                       |   7 +
 kernel/cpu.c                                  |  50 ++-
 kernel/smpboot.h                              |   2 -
 21 files changed, 492 insertions(+), 116 deletions(-)
  

On Tue, Mar 28, 2023 at 08:57:58PM +0100, Usama Arif wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
> 
> Enable parallel bringup for SEV-ES guests. The APs can't actually
> execute the CPUID instruction directly during early startup, but they
> can make the GHCB call directly instead, just as the VC trap handler
> would do.
> 
> Thanks to Sabin for talking me through the way this works.
> 
> Suggested-by: Sabin Rapan <sabrapan@amazon.com>
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> Signed-off-by: Usama Arif <usama.arif@bytedance.com>
> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  arch/x86/coco/core.c              |  5 ++++
>  arch/x86/include/asm/coco.h       |  1 +
>  arch/x86/include/asm/sev-common.h |  3 +++
>  arch/x86/include/asm/smp.h        |  5 +++-
>  arch/x86/kernel/head_64.S         | 30 ++++++++++++++++++++++++
>  arch/x86/kernel/smpboot.c         | 39 ++++++++++++++++++++++++++-----
>  6 files changed, 76 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
> index 49b44f881484..0bab38efb15a 100644
> --- a/arch/x86/coco/core.c
> +++ b/arch/x86/coco/core.c
> @@ -129,6 +129,11 @@ u64 cc_mkdec(u64 val)
>  }
>  EXPORT_SYMBOL_GPL(cc_mkdec);
>  
> +enum cc_vendor cc_get_vendor(void)
> +{
> +	return vendor;
> +}
> +
>  __init void cc_set_vendor(enum cc_vendor v)
>  {
>  	vendor = v;
> diff --git a/arch/x86/include/asm/coco.h b/arch/x86/include/asm/coco.h
> index 3d98c3a60d34..0428d9712c96 100644
> --- a/arch/x86/include/asm/coco.h
> +++ b/arch/x86/include/asm/coco.h
> @@ -12,6 +12,7 @@ enum cc_vendor {
>  };
>  
>  void cc_set_vendor(enum cc_vendor v);
> +enum cc_vendor cc_get_vendor(void);
>  void cc_set_mask(u64 mask);
>  
>  #ifdef CONFIG_ARCH_HAS_CC_PLATFORM

You don't need those hunks adding cc_set_vendor() anymore:

https://git.kernel.org/tip/5ae57743f578725a5dadb6f31d7798ee55e6e967
  

On Tue, Mar 28 2023 at 22:07, Borislav Petkov wrote:
>>  void cc_set_vendor(enum cc_vendor v);
>> +enum cc_vendor cc_get_vendor(void);
>>  void cc_set_mask(u64 mask);
>>  
>>  #ifdef CONFIG_ARCH_HAS_CC_PLATFORM
>
> You don't need those hunks adding cc_set_vendor() anymore:
>
> https://git.kernel.org/tip/5ae57743f578725a5dadb6f31d7798ee55e6e967

That's not really true. The series is based on the x86/apic branch as
the prerequites are in that brnach and that commit is in x86/sev.

That's an x86 maintainer issue to sort out, really.

Thanks,

        tglx
  

On Thu, Mar 30, 2023 at 02:10:56AM +0200, Thomas Gleixner wrote:
> That's not really true. The series is based on the x86/apic branch as
> the prerequites are in that brnach and that commit is in x86/sev.
> 
> That's an x86 maintainer issue to sort out, really.

Why do you think I left this note?

So that when you decide to pick up the rest of the parallel bringup
stuff, you can see it, find me on IRC and we figure out how to do the
tip patch tetris.

:-P
  

On Thu, Mar 30 2023 at 02:10, Thomas Gleixner wrote:
> On Tue, Mar 28 2023 at 22:07, Borislav Petkov wrote:
>>>  void cc_set_vendor(enum cc_vendor v);
>>> +enum cc_vendor cc_get_vendor(void);
>>>  void cc_set_mask(u64 mask);
>>>  
>>>  #ifdef CONFIG_ARCH_HAS_CC_PLATFORM
>>
>> You don't need those hunks adding cc_set_vendor() anymore:
>>
>> https://git.kernel.org/tip/5ae57743f578725a5dadb6f31d7798ee55e6e967
>
> That's not really true. The series is based on the x86/apic branch as
> the prerequites are in that brnach and that commit is in x86/sev.
>
> That's an x86 maintainer issue to sort out, really.

Aside of that, this needs a wrapper when CONFIG_ARCH_HAS_CC_PLATFORM is
not set to be usable outside of CC specific code...

Thanks,

        tglx