Re: [Patch v2 15/24] perf/x86/intel: Add SSP register support for arch-PEBS

[Peter Zijlstra]

On Tue, Feb 18, 2025 at 03:28:09PM +0000, Dapeng Mi wrote:

> @@ -651,6 +651,16 @@ int x86_pmu_hw_config(struct perf_event *event)
>  			return -EINVAL;
>  	}
>  
> +	/* sample_regs_user never support SSP register. */
> +	if (unlikely(event->attr.sample_regs_user & BIT_ULL(PERF_REG_X86_SSP)))
> +		return -EINVAL;

We can easily enough read user SSP, no?

Should be possible even on todays machines; MSR_IA32_PL3_SSP provides.