Re: [PATCH v4 6/7] perf/x86/amd/core: Add PerfMonV2 overflow handling

[Like Xu]

On 27/4/2022 7:31 pm, Sandipan Das wrote:
> +static inline void amd_pmu_ack_global_status(u64 status)
> +{
> +	/*
> +	 * PerfCntrGlobalStatus is read-only but an overflow acknowledgment

If wrmsrl PerfCntrGlobalStatus, remain silent or report #GP ?

> +	 * mechanism exists; writing 1 to a bit in PerfCntrGlobalStatusClr
> +	 * clears the same bit in PerfCntrGlobalStatus
> +	 */
> +
> +	/* Only allow modifications to PerfCntrGlobalStatus.PerfCntrOvfl */
> +	status &= amd_pmu_global_cntr_mask;
> +	wrmsrl(MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR, status);

If rdmsrl PerfCntrGlobalStatusClr, does it return 0 or the value of 
PerfCntrGlobalStatus ?

> +}