Re: [PATCH] KVM: Add missing emulation failure report in kvm_mmu_page_fault()

[Sheng Yang <sheng@linux.intel.com>]

On Sunday 17 January 2010 20:34:23 Avi Kivity wrote:
> On 01/15/2010 10:44 AM, Sheng Yang wrote:
> > Currently we only have handle_invalid_guest_state() reported emulation
> > failure...
> >
> > Signed-off-by: Sheng Yang<sheng@linux.intel.com>
> > ---
> >   arch/x86/kvm/mmu.c |    1 +
> >   1 files changed, 1 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> > index 4f5508c..037e52a 100644
> > --- a/arch/x86/kvm/mmu.c
> > +++ b/arch/x86/kvm/mmu.c
> > @@ -2791,6 +2791,7 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t
> > cr2, u32 error_code) ++vcpu->stat.mmio_exits;
> >   		return 0;
> >   	case EMULATE_FAIL:
> > +		kvm_report_emulation_failure(vcpu, "emulation failure");
> >   		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
> >   		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
> >   		vcpu->run->internal.ndata = 0;
> 
> This is intentional - instead of spamming dmesg, we exit with an
> internal error.  Modern qemu-kvm will halt and allow the user to inspect
> the guest with the built-in disassembler.
> 
I think keep it there still useful for some users. And we have the same report 
in handle_invalid_guest_state(), and we even have "emulation failure, check 
dmesg for details" in QEmu when handling KVM_INTERNAL_ERROR_EMULATION.

I think add one line here is the easiest way to keep consistence, and is 
handy.

-- 
regards
Yang, Sheng