Re: Why so many vm exits caused by ept violation

[Gleb Natapov <gleb@redhat.com>]

On Tue, Nov 09, 2010 at 03:37:44PM +0800, lidong chen wrote:
> sorry,i take mistake,
> 
> the ept violation is not caused by 2M hugepages, but caused by e1000
> emulated by qemu.
> I test uesd 2M hugepages and virio, the performance is better than
> e1000. but is still worse than xen. I will continue to find out other
> reason.
> 
> 
> 
> so, there are two question:
> 1.why have so many ept violation when used e1000?
> 
> 
> 2.when used virtio, there ara also such error happen.is this normal?
> I add the printk in function tdp_page_fault below.
>         pfn = gfn_to_pfn(vcpu->kvm, gfn);
>         if (is_error_pfn(pfn)) {
>                 kvm_release_pfn_clean(pfn);
>                 if( printk_ratelimit() ) {
>                         printk(KERN_EMERG "error gpa is %ld\n", gpa);
>                 }
>                 return is_fault_pfn(pfn) ? -EFAULT : 1;
>         }
> 
> and result is:
> [root@rhel6-kvm1 ~]# dmesg -c
> __ratelimit: 387 callbacks suppressed
> error gpa is 4273995776
> error gpa is 4273995776
> error gpa is 4273995776
> error gpa is 4273995776
> error gpa is 4273995776
> 
You should really print this in hex :) This is 0xfec00000 AKA
IOAPIC. Try to configure virtio to use MSI.

--
			Gleb.