linux-kernel - Re: [Xen-devel] [PATCH] xen: Make VPMU init message look less scary

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Message-ID: <20160801141139.GE21356@char.us.oracle.com>
Date:	Mon, 1 Aug 2016 10:11:39 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Juergen Gross <jgross@...e.com>
Cc:	linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org,
	boris.ostrovsky@...cle.com, david.vrabel@...rix.com
Subject: Re: [Xen-devel] [PATCH] xen: Make VPMU init message look less scary

On Mon, Aug 01, 2016 at 01:41:20PM +0200, Juergen Gross wrote:
> The default for the Xen hypervisor is to not enable VPMU in order to
> avoid security issues. In this case the Linux kernel will issue the
> message "Could not initialize VPMU for cpu 0, error -95" which looks
> more like an error than a normal state.
> 
> Change the message to something less scary in case the hypervisor
> returns EOPNOTSUPP when trying to activate VPMU.
> 
> Signed-off-by: Juergen Gross <jgross@...e.com>
> ---
>  arch/x86/xen/pmu.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/xen/pmu.c b/arch/x86/xen/pmu.c
> index 32bdc2c..e9d66fa 100644
> --- a/arch/x86/xen/pmu.c
> +++ b/arch/x86/xen/pmu.c
> @@ -547,8 +547,11 @@ void xen_pmu_init(int cpu)
>  	return;
>  
>  fail:
> -	pr_info_once("Could not initialize VPMU for cpu %d, error %d\n",
> -		cpu, err);
> +	if (err == -EOPNOTSUPP)
> +		pr_info_once("VPMU usage disabled due to Xen settings\n");

How about 'VPMU disabled by hypevisor.'

> +	else
> +		pr_info_once("Could not initialize VPMU for cpu %d, error %d\n",
> +			cpu, err);
>  	free_pages((unsigned long)xenpmu_data, 0);
>  }
>  
> -- 
> 2.6.6
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@...ts.xen.org
> https://lists.xen.org/xen-devel