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From: Isaku Yamahata <isaku.yamahata@gmail.com>
To: Marc Zyngier <maz@kernel.org>
Cc: isaku.yamahata@intel.com, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will@kernel.org>,
	isaku.yamahata@gmail.com, Kai Huang <kai.huang@intel.com>,
	Chao Gao <chao.gao@intel.com>,
	Atish Patra <atishp@atishpatra.org>,
	Shaokun Zhang <zhangshaokun@hisilicon.com>,
	John Garry <john.garry@huawei.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Huang Ying <ying.huang@intel.com>,
	Huacai Chen <chenhuacai@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH v3 00/22] KVM: hardware enable/disable reorganize
Date: Tue, 6 Sep 2022 15:25:57 -0700	[thread overview]
Message-ID: <20220906222557.GB443010@ls.amr.corp.intel.com> (raw)
In-Reply-To: <87tu5lvnk0.wl-maz@kernel.org>

On Mon, Sep 05, 2022 at 04:38:39PM +0100,
Marc Zyngier <maz@kernel.org> wrote:

> On Fri, 02 Sep 2022 03:17:35 +0100,
> isaku.yamahata@intel.com wrote:
> > 
> > From: Isaku Yamahata <isaku.yamahata@intel.com>
> > 
> > Changes from v2:
> > - Replace the first patch("KVM: x86: Drop kvm_user_return_msr_cpu_online()")
> >   with Sean's implementation
> > - Included all patches of "Improve KVM's interaction with CPU hotplug" [2]
> >   Until v2, Tried to cherry-pick the least patches of it. It turned out that
> >   all the patches are desirable.
> > 
> > This patch series is to implement the suggestion by Sean Christopherson [1]
> > to reorganize enable/disable cpu virtualization feature by replacing
> > the arch-generic current enable/disable logic with PM related hooks. And
> > convert kvm/x86 to use new hooks.
> 
> This series totally breaks on arm64 when playing with CPU hotplug. It
> very much looks like preemption is now enabled in situations where we
> don't expect it to (see below for the full-blown horror show). And
> given the way it shows up in common code, I strongly suspect this
> affects other architectures too.
> 
> Note that if I only take patch #6 (with the subsequent fix that I
> posted this morning), the system is perfectly happy with CPUs being
> hotplugged on/off ad-nauseam.
> 

Thanks for testing. As the discussion in 10/22, it seems like we need to relax
the condition of WARN_ON or BUG_ON of preemptible(). Let me cook a version
to relax it.

-- 
Isaku Yamahata <isaku.yamahata@gmail.com>

      reply	other threads:[~2022-09-06 22:26 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-02  2:17 [PATCH v3 00/22] KVM: hardware enable/disable reorganize isaku.yamahata
2022-09-02  2:17 ` [PATCH v3 01/22] KVM: x86: Drop kvm_user_return_msr_cpu_online() isaku.yamahata
2022-09-05  1:59   ` Chao Gao
2022-09-05  5:30   ` Yuan Yao
2022-09-02  2:17 ` [PATCH v3 02/22] KVM: x86: Use this_cpu_ptr() instead of per_cpu_ptr(smp_processor_id()) isaku.yamahata
2022-09-05  5:35   ` Yuan Yao
2022-09-02  2:17 ` [PATCH v3 03/22] KVM: x86: Move check_processor_compatibility from init ops to runtime ops isaku.yamahata
2022-09-05  5:42   ` Yuan Yao
2022-09-02  2:17 ` [PATCH v3 04/22] Partially revert "KVM: Pass kvm_init()'s opaque param to additional arch funcs" isaku.yamahata
2022-09-05  5:48   ` Yuan Yao
2022-09-02  2:17 ` [PATCH v3 05/22] KVM: Provide more information in kernel log if hardware enabling fails isaku.yamahata
2022-09-05  5:56   ` Yuan Yao
2022-09-02  2:17 ` [PATCH v3 06/22] KVM: arm64: Simplify the CPUHP logic isaku.yamahata
2022-09-05  7:05   ` Yuan Yao
2022-09-05  9:29     ` Marc Zyngier
2022-09-05 12:39       ` Marc Zyngier
2022-09-07 15:12         ` Isaku Yamahata
2022-09-02  2:17 ` [PATCH v3 07/22] KVM: Rename and move CPUHP_AP_KVM_STARTING to ONLINE section isaku.yamahata
2022-09-05  7:49   ` Yuan Yao
2022-09-02  2:17 ` [PATCH v3 08/22] KVM: Do compatibility checks on hotplugged CPUs isaku.yamahata
2022-09-06  1:25   ` Yuan Yao
2022-09-02  2:17 ` [PATCH v3 09/22] KVM: Do processor compatibility check on resume isaku.yamahata
2022-09-05  8:40   ` Yuan Yao
2022-09-05  9:27     ` Yuan Yao
2022-09-08 18:21       ` Isaku Yamahata
2022-09-02  2:17 ` [PATCH v3 10/22] KVM: Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock isaku.yamahata
2022-09-06  2:46   ` Yuan Yao
2022-09-06  6:32     ` Marc Zyngier
2022-09-06 21:44       ` Isaku Yamahata
2022-09-08 18:24         ` Isaku Yamahata
2022-09-02  2:17 ` [PATCH v3 11/22] KVM: Add arch hooks for PM events with empty stub isaku.yamahata
2022-09-06  6:25   ` Yuan Yao
2022-09-08 19:11     ` Isaku Yamahata
2022-09-02  2:17 ` [PATCH v3 12/22] KVM: x86: Move TSC fixup logic to KVM arch resume callback isaku.yamahata
2022-09-02  2:17 ` [PATCH v3 13/22] KVM: Add arch hook when VM is added/deleted isaku.yamahata
2022-09-02  2:17 ` [PATCH v3 14/22] KVM: Move out KVM arch PM hooks and hardware enable/disable logic isaku.yamahata
2022-09-06  7:43   ` Yuan Yao
2022-09-08 19:15     ` Isaku Yamahata
2022-09-02  2:17 ` [PATCH v3 15/22] KVM: kvm_arch.c: Remove _nolock post fix isaku.yamahata
2022-09-02  2:17 ` [PATCH v3 16/22] KVM: kvm_arch.c: Remove a global variable, hardware_enable_failed isaku.yamahata
2022-09-07  5:56   ` Yuan Yao
2022-09-08 22:51     ` Isaku Yamahata
2022-09-02  2:17 ` [PATCH v3 17/22] KVM: x86: Duplicate arch callbacks related to pm events isaku.yamahata
2022-09-02  2:17 ` [PATCH v3 18/22] KVM: Eliminate kvm_arch_post_init_vm() isaku.yamahata
2022-09-02  2:17 ` [PATCH v3 19/22] KVM: x86: Delete kvm_arch_hardware_enable/disable() isaku.yamahata
2022-09-02  2:17 ` [PATCH v3 20/22] KVM: Add config to not compile kvm_arch.c isaku.yamahata
2022-09-02  2:17 ` [PATCH v3 21/22] RFC: KVM: x86: Remove cpus_hardware_enabled and related sanity check isaku.yamahata
2022-09-02  2:17 ` [PATCH v3 22/22] RFC: KVM: " isaku.yamahata
2022-09-05 15:38 ` [PATCH v3 00/22] KVM: hardware enable/disable reorganize Marc Zyngier
2022-09-06 22:25   ` Isaku Yamahata [this message]

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