Re: Why so many vm exits caused by ept violation

[Gleb Natapov <gleb@redhat.com>]

On Tue, Nov 09, 2010 at 05:04:15PM +0800, lidong chen wrote:
> how to configure virtio to use MSI? I didn't found out it.
> thanks.
> 
It looks like it should be enabled by default. What is you guest?

> 2010/11/9 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.
> >

--
			Gleb.