Re: [v3][PATCH 1/2] KVM: x86: don't print when fail to read/write pv eoi memory

[Vitaly Kuznetsov <vkuznets@redhat.com>]

Li RongQing <lirongqing@baidu.com> writes:

> If guest gives MSR_KVM_PV_EOI_EN a wrong value, this printk() will
> be trigged, and kernel log is spammed with the useless message
>
> Fixes: 0d88800d5472 ("kvm: x86: ioapic and apic debug macros cleanup")
> Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> Signed-off-by: Li RongQing <lirongqing@baidu.com>

Paolo,

I'd Cc: stable@ here as these messages are not even ratelimited.

> ---
>  arch/x86/kvm/lapic.c |   18 ++++++------------
>  1 files changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index d6ac32f..752c48e 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -676,31 +676,25 @@ static inline bool pv_eoi_enabled(struct kvm_vcpu *vcpu)
>  static bool pv_eoi_get_pending(struct kvm_vcpu *vcpu)
>  {
>  	u8 val;
> -	if (pv_eoi_get_user(vcpu, &val) < 0) {
> -		printk(KERN_WARNING "Can't read EOI MSR value: 0x%llx\n",
> -			   (unsigned long long)vcpu->arch.pv_eoi.msr_val);
> +	if (pv_eoi_get_user(vcpu, &val) < 0)
>  		return false;
> -	}
> +
>  	return val & KVM_PV_EOI_ENABLED;
>  }
>  
>  static void pv_eoi_set_pending(struct kvm_vcpu *vcpu)
>  {
> -	if (pv_eoi_put_user(vcpu, KVM_PV_EOI_ENABLED) < 0) {
> -		printk(KERN_WARNING "Can't set EOI MSR value: 0x%llx\n",
> -			   (unsigned long long)vcpu->arch.pv_eoi.msr_val);
> +	if (pv_eoi_put_user(vcpu, KVM_PV_EOI_ENABLED) < 0)
>  		return;
> -	}
> +
>  	__set_bit(KVM_APIC_PV_EOI_PENDING, &vcpu->arch.apic_attention);
>  }
>  
>  static void pv_eoi_clr_pending(struct kvm_vcpu *vcpu)
>  {
> -	if (pv_eoi_put_user(vcpu, KVM_PV_EOI_DISABLED) < 0) {
> -		printk(KERN_WARNING "Can't clear EOI MSR value: 0x%llx\n",
> -			   (unsigned long long)vcpu->arch.pv_eoi.msr_val);
> +	if (pv_eoi_put_user(vcpu, KVM_PV_EOI_DISABLED) < 0)
>  		return;
> -	}
> +
>  	__clear_bit(KVM_APIC_PV_EOI_PENDING, &vcpu->arch.apic_attention);
>  }

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>

-- 
Vitaly