[PATCH] KVM: x86: Allow suppressing prints on RDMSR/WRMSR of unhandled MSRs

[PATCH] KVM: x86: Allow suppressing prints on RDMSR/WRMSR of unhandled MSRs

[Eyal Moscovici]

Some guests use these unhandled MSRs very frequently.
This cause dmesg to be populated with lots of aggregated messages on
usage of ignored MSRs. As ignore_msrs=true means that the user is
well-aware his guest use ignored MSRs, allow to also disable the
prints on their usage.

An example of such guest is ESXi which tends to access a lot to MSR
0x34 (MSR_SMI_COUNT) very frequently.

In addition, we have observed this to cause unnecessary delays to
guest execution. Such an example is ESXi which experience networking
delays in it's guests (L2 guests) because of these prints (even when
prints are rate-limited). This can easily be reproduced by pinging
from one L2 guest to another.  Once in a while, a peak in ping RTT
will be observed. Removing these unhandled MSR prints solves the
issue.

Because these prints can help diagnose issues with guests,
this commit only suppress them by a module parameter instead of
removing them from code entirely.

Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/kvm/x86.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 03869eb..21c0059 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -107,6 +107,9 @@
 static bool __read_mostly ignore_msrs = 0;
 module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
 
+static bool __read_mostly suppress_ignore_msrs_prints = false;
+module_param(suppress_ignore_msrs_prints, bool, S_IRUGO | S_IWUSR);
+
 unsigned int min_timer_period_us = 500;
 module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);
 
@@ -2317,7 +2320,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		/* Drop writes to this legacy MSR -- see rdmsr
 		 * counterpart for further detail.
 		 */
-		vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n", msr, data);
+		if (!suppress_ignore_msrs_prints)
+			vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n",
+				msr, data);
 		break;
 	case MSR_AMD64_OSVW_ID_LENGTH:
 		if (!guest_cpuid_has(vcpu, X86_FEATURE_OSVW))
@@ -2354,8 +2359,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 				    msr, data);
 			return 1;
 		} else {
-			vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n",
-				    msr, data);
+			if (!suppress_ignore_msrs_prints)
+				vcpu_unimpl(vcpu,
+					"ignored wrmsr: 0x%x data 0x%llx\n",
+					msr, data);
 			break;
 		}
 	}
@@ -2573,7 +2580,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 					       msr_info->index);
 			return 1;
 		} else {
-			vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n", msr_info->index);
+			if (!suppress_ignore_msrs_prints)
+				vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n",
+					msr_info->index);
 			msr_info->data = 0;
 		}
 		break;
-- 
1.9.1

Re: [PATCH] KVM: x86: Allow suppressing prints on RDMSR/WRMSR of unhandled MSRs

[Paolo Bonzini]

On 08/11/2017 13:32, Eyal Moscovici wrote:
> Some guests use these unhandled MSRs very frequently.
> This cause dmesg to be populated with lots of aggregated messages on
> usage of ignored MSRs. As ignore_msrs=true means that the user is
> well-aware his guest use ignored MSRs, allow to also disable the
> prints on their usage.
> 
> An example of such guest is ESXi which tends to access a lot to MSR
> 0x34 (MSR_SMI_COUNT) very frequently.

For this particular MSR, it can be a good idea to implement it actually. :)

Paolo

> In addition, we have observed this to cause unnecessary delays to
> guest execution. Such an example is ESXi which experience networking
> delays in it's guests (L2 guests) because of these prints (even when
> prints are rate-limited). This can easily be reproduced by pinging
> from one L2 guest to another.  Once in a while, a peak in ping RTT
> will be observed. Removing these unhandled MSR prints solves the
> issue.
> 
> Because these prints can help diagnose issues with guests,
> this commit only suppress them by a module parameter instead of
> removing them from code entirely.
> 
> Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
> Reviewed-by: Liran Alon <liran.alon@oracle.com>
> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  arch/x86/kvm/x86.c | 17 +++++++++++++----
>  1 file changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 03869eb..21c0059 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -107,6 +107,9 @@
>  static bool __read_mostly ignore_msrs = 0;
>  module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
>  
> +static bool __read_mostly suppress_ignore_msrs_prints = false;
> +module_param(suppress_ignore_msrs_prints, bool, S_IRUGO | S_IWUSR);
> +
>  unsigned int min_timer_period_us = 500;
>  module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);
>  
> @@ -2317,7 +2320,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  		/* Drop writes to this legacy MSR -- see rdmsr
>  		 * counterpart for further detail.
>  		 */
> -		vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n", msr, data);
> +		if (!suppress_ignore_msrs_prints)
> +			vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n",
> +				msr, data);
>  		break;
>  	case MSR_AMD64_OSVW_ID_LENGTH:
>  		if (!guest_cpuid_has(vcpu, X86_FEATURE_OSVW))
> @@ -2354,8 +2359,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  				    msr, data);
>  			return 1;
>  		} else {
> -			vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n",
> -				    msr, data);
> +			if (!suppress_ignore_msrs_prints)
> +				vcpu_unimpl(vcpu,
> +					"ignored wrmsr: 0x%x data 0x%llx\n",
> +					msr, data);
>  			break;
>  		}
>  	}
> @@ -2573,7 +2580,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>  					       msr_info->index);
>  			return 1;
>  		} else {
> -			vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n", msr_info->index);
> +			if (!suppress_ignore_msrs_prints)
> +				vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n",
> +					msr_info->index);
>  			msr_info->data = 0;
>  		}
>  		break;
> 

Re: [PATCH] KVM: x86: Allow suppressing prints on RDMSR/WRMSR of unhandled MSRs

[Eyal Moscovici]

On 08/11/17 15:11, Paolo Bonzini wrote:
> On 08/11/2017 13:32, Eyal Moscovici wrote:
>> Some guests use these unhandled MSRs very frequently.
>> This cause dmesg to be populated with lots of aggregated messages on
>> usage of ignored MSRs. As ignore_msrs=true means that the user is
>> well-aware his guest use ignored MSRs, allow to also disable the
>> prints on their usage.
>>
>> An example of such guest is ESXi which tends to access a lot to MSR
>> 0x34 (MSR_SMI_COUNT) very frequently.
> For this particular MSR, it can be a good idea to implement it actually. :)
>
> Paolo
Agreed as this is fairly simple. Have implemented. We will submit a 
patch very soon.

However, I still think this patch of suppressing prints of usage of 
ignored MSRs is useful as it can spam the dmesg when ignored_msrs=true. 
We have seen other guests that also make frequent usage of other MSRs 
such as esoteric CPU perf MSRs and etc.
>> In addition, we have observed this to cause unnecessary delays to
>> guest execution. Such an example is ESXi which experience networking
>> delays in it's guests (L2 guests) because of these prints (even when
>> prints are rate-limited). This can easily be reproduced by pinging
>> from one L2 guest to another.  Once in a while, a peak in ping RTT
>> will be observed. Removing these unhandled MSR prints solves the
>> issue.
>>
>> Because these prints can help diagnose issues with guests,
>> this commit only suppress them by a module parameter instead of
>> removing them from code entirely.
>>
>> Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
>> Reviewed-by: Liran Alon <liran.alon@oracle.com>
>> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
>> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>> ---
>>   arch/x86/kvm/x86.c | 17 +++++++++++++----
>>   1 file changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index 03869eb..21c0059 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -107,6 +107,9 @@
>>   static bool __read_mostly ignore_msrs = 0;
>>   module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
>>   
>> +static bool __read_mostly suppress_ignore_msrs_prints = false;
>> +module_param(suppress_ignore_msrs_prints, bool, S_IRUGO | S_IWUSR);
>> +
>>   unsigned int min_timer_period_us = 500;
>>   module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);
>>   
>> @@ -2317,7 +2320,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>>   		/* Drop writes to this legacy MSR -- see rdmsr
>>   		 * counterpart for further detail.
>>   		 */
>> -		vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n", msr, data);
>> +		if (!suppress_ignore_msrs_prints)
>> +			vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n",
>> +				msr, data);
>>   		break;
>>   	case MSR_AMD64_OSVW_ID_LENGTH:
>>   		if (!guest_cpuid_has(vcpu, X86_FEATURE_OSVW))
>> @@ -2354,8 +2359,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>>   				    msr, data);
>>   			return 1;
>>   		} else {
>> -			vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n",
>> -				    msr, data);
>> +			if (!suppress_ignore_msrs_prints)
>> +				vcpu_unimpl(vcpu,
>> +					"ignored wrmsr: 0x%x data 0x%llx\n",
>> +					msr, data);
>>   			break;
>>   		}
>>   	}
>> @@ -2573,7 +2580,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>>   					       msr_info->index);
>>   			return 1;
>>   		} else {
>> -			vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n", msr_info->index);
>> +			if (!suppress_ignore_msrs_prints)
>> +				vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n",
>> +					msr_info->index);
>>   			msr_info->data = 0;
>>   		}
>>   		break;
>>

Re: [PATCH] KVM: x86: Allow suppressing prints on RDMSR/WRMSR of unhandled MSRs

[Paolo Bonzini]

On 09/11/2017 09:15, Eyal Moscovici wrote:
> 
> 
> On 08/11/17 15:11, Paolo Bonzini wrote:
>> On 08/11/2017 13:32, Eyal Moscovici wrote:
>>> Some guests use these unhandled MSRs very frequently.
>>> This cause dmesg to be populated with lots of aggregated messages on
>>> usage of ignored MSRs. As ignore_msrs=true means that the user is
>>> well-aware his guest use ignored MSRs, allow to also disable the
>>> prints on their usage.
>>>
>>> An example of such guest is ESXi which tends to access a lot to MSR
>>> 0x34 (MSR_SMI_COUNT) very frequently.
>>
>> For this particular MSR, it can be a good idea to implement it
>> actually. :)
>
> Agreed as this is fairly simple. Have implemented. We will submit a
> patch very soon.
> 
> However, I still think this patch of suppressing prints of usage of
> ignored MSRs is useful as it can spam the dmesg when ignored_msrs=true.
> We have seen other guests that also make frequent usage of other MSRs
> such as esoteric CPU perf MSRs and etc.

Yes, sorry---it wasn't meant as a rejection of this patch.

Paolo


>>> In addition, we have observed this to cause unnecessary delays to
>>> guest execution. Such an example is ESXi which experience networking
>>> delays in it's guests (L2 guests) because of these prints (even when
>>> prints are rate-limited). This can easily be reproduced by pinging
>>> from one L2 guest to another.  Once in a while, a peak in ping RTT
>>> will be observed. Removing these unhandled MSR prints solves the
>>> issue.
>>>
>>> Because these prints can help diagnose issues with guests,
>>> this commit only suppress them by a module parameter instead of
>>> removing them from code entirely.
>>>
>>> Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
>>> Reviewed-by: Liran Alon <liran.alon@oracle.com>
>>> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
>>> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
>>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>>> ---
>>>   arch/x86/kvm/x86.c | 17 +++++++++++++----
>>>   1 file changed, 13 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>>> index 03869eb..21c0059 100644
>>> --- a/arch/x86/kvm/x86.c
>>> +++ b/arch/x86/kvm/x86.c
>>> @@ -107,6 +107,9 @@
>>>   static bool __read_mostly ignore_msrs = 0;
>>>   module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
>>>   +static bool __read_mostly suppress_ignore_msrs_prints = false;
>>> +module_param(suppress_ignore_msrs_prints, bool, S_IRUGO | S_IWUSR);
>>> +
>>>   unsigned int min_timer_period_us = 500;
>>>   module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);
>>>   @@ -2317,7 +2320,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu,
>>> struct msr_data *msr_info)
>>>           /* Drop writes to this legacy MSR -- see rdmsr
>>>            * counterpart for further detail.
>>>            */
>>> -        vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n", msr,
>>> data);
>>> +        if (!suppress_ignore_msrs_prints)
>>> +            vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n",
>>> +                msr, data);
>>>           break;
>>>       case MSR_AMD64_OSVW_ID_LENGTH:
>>>           if (!guest_cpuid_has(vcpu, X86_FEATURE_OSVW))
>>> @@ -2354,8 +2359,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu,
>>> struct msr_data *msr_info)
>>>                       msr, data);
>>>               return 1;
>>>           } else {
>>> -            vcpu_unimpl(vcpu, "ignored wrmsr: 0x%x data 0x%llx\n",
>>> -                    msr, data);
>>> +            if (!suppress_ignore_msrs_prints)
>>> +                vcpu_unimpl(vcpu,
>>> +                    "ignored wrmsr: 0x%x data 0x%llx\n",
>>> +                    msr, data);
>>>               break;
>>>           }
>>>       }
>>> @@ -2573,7 +2580,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu,
>>> struct msr_data *msr_info)
>>>                              msr_info->index);
>>>               return 1;
>>>           } else {
>>> -            vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n",
>>> msr_info->index);
>>> +            if (!suppress_ignore_msrs_prints)
>>> +                vcpu_unimpl(vcpu, "ignored rdmsr: 0x%x\n",
>>> +                    msr_info->index);
>>>               msr_info->data = 0;
>>>           }
>>>           break;
>>>
> 

Re: [PATCH] KVM: x86: Allow suppressing prints on RDMSR/WRMSR of unhandled MSRs

[Radim Krčmář]

2017-11-08 14:32+0200, Eyal Moscovici:
> Some guests use these unhandled MSRs very frequently.
> This cause dmesg to be populated with lots of aggregated messages on
> usage of ignored MSRs. As ignore_msrs=true means that the user is
> well-aware his guest use ignored MSRs, allow to also disable the
> prints on their usage.
> 
> An example of such guest is ESXi which tends to access a lot to MSR
> 0x34 (MSR_SMI_COUNT) very frequently.
> 
> In addition, we have observed this to cause unnecessary delays to
> guest execution. Such an example is ESXi which experience networking
> delays in it's guests (L2 guests) because of these prints (even when
> prints are rate-limited). This can easily be reproduced by pinging
> from one L2 guest to another.  Once in a while, a peak in ping RTT
> will be observed. Removing these unhandled MSR prints solves the
> issue.
> 
> Because these prints can help diagnose issues with guests,
> this commit only suppress them by a module parameter instead of
> removing them from code entirely.
> 
> Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
> Reviewed-by: Liran Alon <liran.alon@oracle.com>
> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  arch/x86/kvm/x86.c | 17 +++++++++++++----
>  1 file changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 03869eb..21c0059 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -107,6 +107,9 @@
>  static bool __read_mostly ignore_msrs = 0;
>  module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
>  
> +static bool __read_mostly suppress_ignore_msrs_prints = false;
> +module_param(suppress_ignore_msrs_prints, bool, S_IRUGO | S_IWUSR);

What about calling it 'print_ignored_msrs' and default to true?

(I can change that when applying.)

Thanks.

Re: [PATCH] KVM: x86: Allow suppressing prints on RDMSR/WRMSR of unhandled MSRs

[Paolo Bonzini]

On 09/11/2017 16:22, Radim Krčmář wrote:
> 2017-11-08 14:32+0200, Eyal Moscovici:
>> Some guests use these unhandled MSRs very frequently.
>> This cause dmesg to be populated with lots of aggregated messages on
>> usage of ignored MSRs. As ignore_msrs=true means that the user is
>> well-aware his guest use ignored MSRs, allow to also disable the
>> prints on their usage.
>>
>> An example of such guest is ESXi which tends to access a lot to MSR
>> 0x34 (MSR_SMI_COUNT) very frequently.
>>
>> In addition, we have observed this to cause unnecessary delays to
>> guest execution. Such an example is ESXi which experience networking
>> delays in it's guests (L2 guests) because of these prints (even when
>> prints are rate-limited). This can easily be reproduced by pinging
>> from one L2 guest to another.  Once in a while, a peak in ping RTT
>> will be observed. Removing these unhandled MSR prints solves the
>> issue.
>>
>> Because these prints can help diagnose issues with guests,
>> this commit only suppress them by a module parameter instead of
>> removing them from code entirely.
>>
>> Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
>> Reviewed-by: Liran Alon <liran.alon@oracle.com>
>> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
>> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>> ---
>>  arch/x86/kvm/x86.c | 17 +++++++++++++----
>>  1 file changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index 03869eb..21c0059 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -107,6 +107,9 @@
>>  static bool __read_mostly ignore_msrs = 0;
>>  module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
>>  
>> +static bool __read_mostly suppress_ignore_msrs_prints = false;
>> +module_param(suppress_ignore_msrs_prints, bool, S_IRUGO | S_IWUSR);
> 
> What about calling it 'print_ignored_msrs' and default to true?

Makes sense! s/print/report/ perhaps?

Thanks,

Paolo

> (I can change that when applying.)
> 
> Thanks.
> 

Re: [PATCH] KVM: x86: Allow suppressing prints on RDMSR/WRMSR of unhandled MSRs

[Radim Krčmář]

2017-11-09 19:30+0100, Paolo Bonzini:
> On 09/11/2017 16:22, Radim Krčmář wrote:
> > 2017-11-08 14:32+0200, Eyal Moscovici:
> >> Some guests use these unhandled MSRs very frequently.
> >> This cause dmesg to be populated with lots of aggregated messages on
> >> usage of ignored MSRs. As ignore_msrs=true means that the user is
> >> well-aware his guest use ignored MSRs, allow to also disable the
> >> prints on their usage.
> >>
> >> An example of such guest is ESXi which tends to access a lot to MSR
> >> 0x34 (MSR_SMI_COUNT) very frequently.
> >>
> >> In addition, we have observed this to cause unnecessary delays to
> >> guest execution. Such an example is ESXi which experience networking
> >> delays in it's guests (L2 guests) because of these prints (even when
> >> prints are rate-limited). This can easily be reproduced by pinging
> >> from one L2 guest to another.  Once in a while, a peak in ping RTT
> >> will be observed. Removing these unhandled MSR prints solves the
> >> issue.
> >>
> >> Because these prints can help diagnose issues with guests,
> >> this commit only suppress them by a module parameter instead of
> >> removing them from code entirely.
> >>
> >> Signed-off-by: Eyal Moscovici <eyal.moscovici@oracle.com>
> >> Reviewed-by: Liran Alon <liran.alon@oracle.com>
> >> Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> >> Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
> >> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> >> ---
> >>  arch/x86/kvm/x86.c | 17 +++++++++++++----
> >>  1 file changed, 13 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> >> index 03869eb..21c0059 100644
> >> --- a/arch/x86/kvm/x86.c
> >> +++ b/arch/x86/kvm/x86.c
> >> @@ -107,6 +107,9 @@
> >>  static bool __read_mostly ignore_msrs = 0;
> >>  module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
> >>  
> >> +static bool __read_mostly suppress_ignore_msrs_prints = false;
> >> +module_param(suppress_ignore_msrs_prints, bool, S_IRUGO | S_IWUSR);
> > 
> > What about calling it 'print_ignored_msrs' and default to true?
> 
> Makes sense! s/print/report/ perhaps?

s/suppress_ignore_msrs_prints/report_ignored_msrs/ and applied, thanks.