[RFC][PATCH] kvm: add suspend pm-notifier

[Peter Zijlstra]

On Fri, Jun 04, 2021 at 01:43:15AM +0900, Sergey Senozhatsky wrote:
> Add KVM suspend/hibernate PM-notifier which lets architectures
> to implement arch-specific VM suspend code. For instance, on x86
> this sets PVCLOCK_GUEST_STOPPED on all the VCPUs.
> 
> Our case is that user puts the host system into sleep multiple
> times a day (e.g. closes the laptop's lid) so we need a reliable
> way to suspend VMs properly.
> 
> Signed-off-by: Sergey Senozhatsky <senozhatsky at chromium.org>
> ---
>  arch/arm64/kvm/arm.c       |  4 ++++
>  arch/mips/kvm/mips.c       |  4 ++++
>  arch/powerpc/kvm/powerpc.c |  4 ++++
>  arch/s390/kvm/kvm-s390.c   |  4 ++++
>  arch/x86/kvm/x86.c         | 21 ++++++++++++++++++++
>  include/linux/kvm_host.h   |  8 ++++++++
>  virt/kvm/kvm_main.c        | 40 ++++++++++++++++++++++++++++++++++++++
>  7 files changed, 85 insertions(+)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 1126eae27400..547dbe44d039 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -1311,6 +1311,10 @@ static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
>  	}
>  }
>  
> +void kvm_arch_pm_notifier(struct kvm *kvm)
> +{
> +}
> +
>  long kvm_arch_vm_ioctl(struct file *filp,
>  		       unsigned int ioctl, unsigned long arg)
>  {
> diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
> index 4d4af97dcc88..d4408acd2be6 100644
> --- a/arch/mips/kvm/mips.c
> +++ b/arch/mips/kvm/mips.c
> @@ -980,6 +980,10 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
>  	kvm_flush_remote_tlbs(kvm);
>  }
>  
> +void kvm_arch_pm_notifier(struct kvm *kvm)
> +{
> +}
> +
>  long kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
>  {
>  	long r;
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index a2a68a958fa0..96e8a7b6fcf0 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -2334,6 +2334,10 @@ static int kvmppc_get_cpu_char(struct kvm_ppc_cpu_char *cp)
>  }
>  #endif
>  
> +void kvm_arch_pm_notifier(struct kvm *kvm)
> +{
> +}
> +
>  long kvm_arch_vm_ioctl(struct file *filp,
>                         unsigned int ioctl, unsigned long arg)
>  {
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index 1296fc10f80c..c5f86fc1e497 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2367,6 +2367,10 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
>  	return r;
>  }
>  
> +void kvm_arch_pm_notifier(struct kvm *kvm)
> +{
> +}
> +
>  long kvm_arch_vm_ioctl(struct file *filp,
>  		       unsigned int ioctl, unsigned long arg)
>  {

What looks like you wants a __weak function.