Re: [v2 PATCH 3/4] x86/kvm: Add host side support for virtual suspend time injection

[Thomas Gleixner]

On Fri, Aug 06 2021 at 19:07, Hikaru Nishida wrote:
>  
> +#ifdef CONFIG_KVM_VIRT_SUSPEND_TIMING
> +void kvm_arch_timekeeping_inject_sleeptime(const struct timespec64 *delta)
> +{
> +	struct kvm_vcpu *vcpu;
> +	u64 suspend_time_ns;
> +	struct kvm *kvm;
> +	s64 adj;
> +	int i;
> +
> +	suspend_time_ns = timespec64_to_ns(delta);
> +	adj = tsc_khz * (suspend_time_ns / 1000000);
> +	/*
> +	 * Adjust TSCs on all vcpus and kvmclock as if they are stopped
> +	 * during host's suspension.
> +	 * Also, cummulative suspend time is recorded in kvm structure and
> +	 * the update will be notified via an interrupt for each vcpu.
> +	 */
> +	mutex_lock(&kvm_lock);

This is invoked from with timekeeper_lock held with interrupts
disabled. How is a mutex_lock() supposed to work here?

Thanks,

        tglx