[PATCH] KVM: PPC: Book3S: Ratelimit copy data failure error messages

[Vipin K Parashar]

Forwarded same patch to kvm at vger.kernel.org

and kvm-ppc at vger.kernel.org too.


On Tuesday 14 February 2017 12:26 AM, Vipin K Parashar wrote:
> kvm_ppc_mmu_book3s_32/64 xlat() log "KVM can't copy data" error
> upon failing to copy user data to kernel space. This floods kernel
> log once such fails occur in short time period. Ratelimit this
> error to avoid flooding kernel logs upon copy data failures.
>
> Signed-off-by: Vipin K Parashar <vipin at linux.vnet.ibm.com>
> ---
>   arch/powerpc/kvm/book3s_32_mmu.c | 3 ++-
>   arch/powerpc/kvm/book3s_64_mmu.c | 3 ++-
>   2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_32_mmu.c b/arch/powerpc/kvm/book3s_32_mmu.c
> index a2eb6d3..ca8f960 100644
> --- a/arch/powerpc/kvm/book3s_32_mmu.c
> +++ b/arch/powerpc/kvm/book3s_32_mmu.c
> @@ -224,7 +224,8 @@ static int kvmppc_mmu_book3s_32_xlate_pte(struct kvm_vcpu *vcpu, gva_t eaddr,
>   	ptem = kvmppc_mmu_book3s_32_get_ptem(sre, eaddr, primary);
>
>   	if(copy_from_user(pteg, (void __user *)ptegp, sizeof(pteg))) {
> -		printk(KERN_ERR "KVM: Can't copy data from 0x%lx!\n", ptegp);
> +		if (printk_ratelimit())
> +			printk(KERN_ERR "KVM: Can't copy data from 0x%lx!\n", ptegp);
>   		goto no_page_found;
>   	}
>
> diff --git a/arch/powerpc/kvm/book3s_64_mmu.c b/arch/powerpc/kvm/book3s_64_mmu.c
> index b9131aa..b420aca 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu.c
> @@ -265,7 +265,8 @@ static int kvmppc_mmu_book3s_64_xlate(struct kvm_vcpu *vcpu, gva_t eaddr,
>   		goto no_page_found;
>
>   	if(copy_from_user(pteg, (void __user *)ptegp, sizeof(pteg))) {
> -		printk(KERN_ERR "KVM can't copy data from 0x%lx!\n", ptegp);
> +		if (printk_ratelimit())
> +			printk(KERN_ERR "KVM can't copy data from 0x%lx!\n", ptegp);
>   		goto no_page_found;
>   	}
>