linux-kernel - Re: [PATCH v3 0/4] KVM: lockdep improvements

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Message-ID: <53a26378fce90c8bbfa57a582992324560aa0274.camel@redhat.com>
Date: Wed, 30 Apr 2025 16:30:51 -0400
From: mlevitsk@...hat.com
To: kvm@...r.kernel.org
Cc: "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org, Randy Dunlap
 <rdunlap@...radead.org>, Paolo Bonzini <pbonzini@...hat.com>, Will Deacon
 <will@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, Kunkun Jiang
 <jiangkunkun@...wei.com>, Jing Zhang <jingzhangos@...gle.com>, Albert Ou
 <aou@...s.berkeley.edu>, Keisuke Nishimura <keisuke.nishimura@...ia.fr>, 
 Anup Patel <anup@...infault.org>, Catalin Marinas
 <catalin.marinas@....com>, Atish Patra <atishp@...shpatra.org>,
 kvmarm@...ts.linux.dev, Waiman Long <longman@...hat.com>,  Boqun Feng
 <boqun.feng@...il.com>, linux-arm-kernel@...ts.infradead.org, Peter
 Zijlstra <peterz@...radead.org>, Dave Hansen <dave.hansen@...ux.intel.com>,
 Paul Walmsley <paul.walmsley@...ive.com>, Suzuki K Poulose
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 <bhelgaas@...gle.com>, Palmer Dabbelt <palmer@...belt.com>, Joey Gouly
 <joey.gouly@....com>, Borislav Petkov <bp@...en8.de>, Sean Christopherson
 <seanjc@...gle.com>, Marc Zyngier <maz@...nel.org>, Alexander Potapenko
 <glider@...gle.com>, Thomas Gleixner <tglx@...utronix.de>,
 linux-kernel@...r.kernel.org,  linux-riscv@...ts.infradead.org, Shusen Li
 <lishusen2@...wei.com>,  kvm-riscv@...ts.infradead.org
Subject: Re: [PATCH v3 0/4] KVM: lockdep improvements

On Wed, 2025-04-30 at 16:23 -0400, Maxim Levitsky wrote:
> This is	a continuation of my 'extract
> lock_all_vcpus/unlock_all_vcpus'
> patch series.
> 
> Implement the suggestion of using lockdep's "nest_lock" feature
> when locking all KVM vCPUs by adding mutex_trylock_nest_lock() and
> mutex_lock_killable_nest_lock() and use these functions	in the
> implementation of the
> kvm_trylock_all_vcpus()/kvm_lock_all_vcpus()/kvm_unlock_all_vcpus().
> 
> Those changes allow removal of a custom workaround that was needed to
> silence the lockdep warning in the SEV code and also stop lockdep
> from
> complaining in case of ARM and RISC-V code which doesn't include the
> above
> mentioned workaround.
> 
> Finally, it's worth noting that this patch series removes a fair
> amount of duplicate code by implementing the logic in one place.
> 
> Best regards,
> 	Maxim Levitsky
> 
> Maxim Levitsky (4):
>   arm64: KVM: use mutex_trylock_nest_lock when locking all vCPUs
>   RISC-V: KVM: switch to kvm_lock/unlock_all_vcpus
>   locking/mutex: implement mutex_lock_killable_nest_lock
>   x86: KVM: SEV: implement kvm_lock_all_vcpus and use it
> 
>  arch/arm64/include/asm/kvm_host.h     |  3 --
>  arch/arm64/kvm/arch_timer.c           |  4 +-
>  arch/arm64/kvm/arm.c                  | 43 ----------------
>  arch/arm64/kvm/vgic/vgic-init.c       |  4 +-
>  arch/arm64/kvm/vgic/vgic-its.c        |  8 +--
>  arch/arm64/kvm/vgic/vgic-kvm-device.c | 12 ++---
>  arch/riscv/kvm/aia_device.c           | 34 +------------
>  arch/x86/kvm/svm/sev.c                | 72 ++-----------------------
> --
>  include/linux/kvm_host.h              |  4 ++
>  include/linux/mutex.h                 | 17 +++++--
>  kernel/locking/mutex.c                |  7 +--
>  virt/kvm/kvm_main.c                   | 59 ++++++++++++++++++++++
>  12 files changed, 100 insertions(+), 167 deletions(-)
> 
> -- 
> 2.46.0
> 
> 

I forgot to send first patch in the series, resending.

Best regards,
	Maxim Levitsky