On Tue, Dec 22, 2015 at 10:24:13AM +0300, Pavel Fedin wrote: > > +On the return path into kvm, user space should set handled to > > +KVM_EXIT_MSR_HANDLED if it successfully handled the MSR access. Otherwise, > > +handled should be set to KVM_EXIT_MSR_UNHANDLED, which will cause a general > > +protection fault to be injected into the vcpu. If an error occurs during > > the > > +return into kvm, the vcpu will not be run and another exit will be > > generated > > +with type set to KVM_EXIT_MSR_COMPLETION_FAILED. > > + > > +If exit_reason is KVM_EXIT_MSR_AFTER_WRITE, then the vcpu has executed a > > wrmsr > > +instruction which is handled by kvm but which user space may need to be > > +notified about. index and data are set as described above; the value of > > type > > +depends on the MSR that was written. handled is ignored on reentry into > > kvm. > > 1. Is there any real need to distinguish between KVM_EXIT_MSR_WRITE and > KVM_EXIT_MSR_AFTER_WRITE ? IMHO from userland's point of view these are the > same.
Indeed. Perhaps the kernel can set .handled to true to let userspace know it already took care of it, instead of introducing yet another exit_reason. The field would need to be marked in/out, then. Roman. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
