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Date:   Mon, 25 Oct 2021 16:06:31 +0200
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Subject: Re: [PATCH v2 19/43] KVM: Add helpers to wake/query blocking vCPU
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To:     Sean Christopherson <seanjc@google.com>,
        Marc Zyngier <maz@kernel.org>,
        Huacai Chen <chenhuacai@kernel.org>,
        Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
        Paul Mackerras <paulus@ozlabs.org>,
        Anup Patel <anup.patel@wdc.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Janosch Frank <frankja@linux.ibm.com>
Cc:     James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Atish Patra <atish.patra@wdc.com>,
        David Hildenbrand <david@redhat.com>,
        Cornelia Huck <cohuck@redhat.com>,
        Claudio Imbrenda <imbrenda@linux.ibm.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        linux-mips@vger.kernel.org, kvm@vger.kernel.org,
        kvm-ppc@vger.kernel.org, kvm-riscv@lists.infradead.org,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        David Matlack <dmatlack@google.com>,
        Oliver Upton <oupton@google.com>,
        Jing Zhang <jingzhangos@google.com>
References: <20211009021236.4122790-1-seanjc@google.com>
 <20211009021236.4122790-20-seanjc@google.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
In-Reply-To: <20211009021236.4122790-20-seanjc@google.com>
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On 09/10/21 04:12, Sean Christopherson wrote:
> diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
> index 7e8396f74010..addd53b6eba6 100644
> --- a/arch/arm64/kvm/arch_timer.c
> +++ b/arch/arm64/kvm/arch_timer.c
> @@ -649,7 +649,6 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu)
>   {
>   	struct arch_timer_cpu *timer = vcpu_timer(vcpu);
>   	struct timer_map map;
> -	struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu);
>   
>   	if (unlikely(!timer->enabled))
>   		return;
> @@ -672,7 +671,7 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu)
>   	if (map.emul_ptimer)
>   		soft_timer_cancel(&map.emul_ptimer->hrtimer);
>   
> -	if (rcuwait_active(wait))
> +	if (kvm_vcpu_is_blocking(vcpu))
>   		kvm_timer_blocking(vcpu);
>   
>   	/*

So this trick is what you're applying to x86 too instead of using 
vmx_pre_block, I see.

Paolo