On Tue, Aug 06, 2019 at 08:01:47AM +0200, Vitaly Kuznetsov wrote: > When we're unable to skip instruction with kvm_emulate_instruction() we > will not advance RIP and most likely the guest will get stuck as > consequitive attempts to execute the same instruction will likely result > in the same behavior. > > As we're not supposed to see these messages under normal conditions, switch > to pr_err_once(). > > Signed-off-by: Vitaly Kuznetsov <[email protected]> > Reviewed-by: Jim Mattson <[email protected]> > --- > arch/x86/kvm/svm.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c > index 7e843b340490..80f576e05112 100644 > --- a/arch/x86/kvm/svm.c > +++ b/arch/x86/kvm/svm.c > @@ -782,7 +782,8 @@ static void skip_emulated_instruction(struct kvm_vcpu > *vcpu) > if (!svm->next_rip) { > if (kvm_emulate_instruction(vcpu, EMULTYPE_SKIP) != > EMULATE_DONE) > - printk(KERN_DEBUG "%s: NOP\n", __func__); > + pr_err_once("KVM: %s: unable to skip instruction\n", > + __func__);
IMO the proper fix would be to change skip_emulated_instruction() to return an int so that emulation failure can be reported back up the stack. It's a relatively minor change as there are a limited number of call sites to skip_emulated_instruction() in SVM and VMX. > return; > } > if (svm->next_rip - kvm_rip_read(vcpu) > MAX_INST_SIZE) > -- > 2.20.1 >
