On Tue, Jul 08, 2014 at 09:49:40AM -0700, kan.liang@intel.com wrote:
> +/*
> + * Under certain circumstances, access certain MSR may cause #GP.
> + * The function tests if the input MSR can be safely accessed.
> + */
> +static inline bool check_msr(unsigned long msr)
> +{
> +	u64 value;
> +
> +	if (rdmsrl_safe(msr, &value) < 0)
> +		return false;
> +	if (wrmsrl_safe(msr, value) < 0)
> +		return false;
> +	return true;
> +}

What does this thing return after patch 2? does the write still fault or
will KVM silently take writes too?