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Subject: Re: [PATCHv3 2/2] kvm: x86: implement KVM PM-notifier
To:     Sergey Senozhatsky <senozhatsky@chromium.org>,
        Marc Zyngier <maz@kernel.org>
Cc:     Vitaly Kuznetsov <vkuznets@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Suleiman Souhlal <suleiman@google.com>, x86@kernel.org,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20210606021045.14159-1-senozhatsky@chromium.org>
 <20210606021045.14159-2-senozhatsky@chromium.org>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <4cb326cf-fba6-9894-980a-34c1a19183f2@redhat.com>
Date:   Thu, 10 Jun 2021 14:15:53 +0200
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On 06/06/21 04:10, Sergey Senozhatsky wrote:
> Implement PM hibernation/suspend prepare notifiers so that KVM
> can reliably set PVCLOCK_GUEST_STOPPED on VCPUs and properly
> suspend VMs.
> 
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> ---
>   arch/x86/kvm/Kconfig |  1 +
>   arch/x86/kvm/x86.c   | 36 ++++++++++++++++++++++++++++++++++++
>   2 files changed, 37 insertions(+)
> 
> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
> index fb8efb387aff..ac69894eab88 100644
> --- a/arch/x86/kvm/Kconfig
> +++ b/arch/x86/kvm/Kconfig
> @@ -43,6 +43,7 @@ config KVM
>   	select KVM_GENERIC_DIRTYLOG_READ_PROTECT
>   	select KVM_VFIO
>   	select SRCU
> +	select HAVE_KVM_PM_NOTIFIER if PM
>   	help
>   	  Support hosting fully virtualized guest machines using hardware
>   	  virtualization extensions.  You will need a fairly recent
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index b594275d49b5..af1ab527a0cb 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -58,6 +58,7 @@
>   #include <linux/sched/isolation.h>
>   #include <linux/mem_encrypt.h>
>   #include <linux/entry-kvm.h>
> +#include <linux/suspend.h>
>   
>   #include <trace/events/kvm.h>
>   
> @@ -5615,6 +5616,41 @@ static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm, void __user *argp)
>   	return 0;
>   }
>   
> +#ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
> +static int kvm_arch_suspend_notifier(struct kvm *kvm)
> +{
> +	struct kvm_vcpu *vcpu;
> +	int i, ret = 0;
> +
> +	mutex_lock(&kvm->lock);
> +	kvm_for_each_vcpu(i, vcpu, kvm) {
> +		if (!vcpu->arch.pv_time_enabled)
> +			continue;
> +
> +		ret = kvm_set_guest_paused(vcpu);
> +		if (ret) {
> +			kvm_err("Failed to pause guest VCPU%d: %d\n",
> +				vcpu->vcpu_id, ret);
> +			break;
> +		}
> +	}
> +	mutex_unlock(&kvm->lock);
> +
> +	return ret ? NOTIFY_BAD : NOTIFY_DONE;
> +}
> +
> +int kvm_arch_pm_notifier(struct kvm *kvm, unsigned long state)
> +{
> +	switch (state) {
> +	case PM_HIBERNATION_PREPARE:
> +	case PM_SUSPEND_PREPARE:
> +		return kvm_arch_suspend_notifier(kvm);
> +	}
> +
> +	return NOTIFY_DONE;
> +}
> +#endif /* CONFIG_HAVE_KVM_PM_NOTIFIER */
> +
>   long kvm_arch_vm_ioctl(struct file *filp,
>   		       unsigned int ioctl, unsigned long arg)
>   {
> 

Queued, thanks.

Paolo