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

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Date:	Mon, 1 Aug 2016 11:50:26 -0400
From:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:	Juergen Gross <jgross@...e.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc:	linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org,
	david.vrabel@...rix.com
Subject: Re: [Xen-devel] [PATCH] xen: Make VPMU init message look less scary

On 08/01/2016 11:48 AM, Juergen Gross wrote:
> On 01/08/16 16:11, Konrad Rzeszutek Wilk wrote:
>> 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.'
> Hmm, why not. Boris, are you okay with this message, too?

Sure.