On Thu, Jun 01, 2023 at 01:30:58PM -0700, Anish Moorthy wrote: > On Thu, Jun 1, 2023 at 12:52 PM Oliver Upton <oliver.upton@xxxxxxxxx> wrote: > > Eventually, you can stuff a bit in there to advertise that all > > EFAULTs are reliable. > > I don't think this is an objective: the idea is to annotate efaults > tracing back to user accesses (see [2]). Although the idea of > annotating with some "unrecoverable" flag set for other efaults has > been tossed around, so we may end up with that. Right, there's quite a bit of detail entailed by what such a bit means... In any case, the idea would be to have a forward-looking stance with the UAPI where we can bolt on more things to the existing CAP in the future. > [2] https://lore.kernel.org/kvm/20230412213510.1220557-1-amoorthy@xxxxxxxxxx/T/#m5715f3a14a6a9ff9a4188918ec105592f0bfc69a > > > [*] https://lore.kernel.org/kvmarm/ZHjqkdEOVUiazj5d@xxxxxxxxxx/ > > > > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > > index cf7d3de6f3689..f3effc93cbef3 100644 > > > --- a/virt/kvm/kvm_main.c > > > +++ b/virt/kvm/kvm_main.c > > > @@ -1142,6 +1142,7 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname) > > > spin_lock_init(&kvm->mn_invalidate_lock); > > > rcuwait_init(&kvm->mn_memslots_update_rcuwait); > > > xa_init(&kvm->vcpu_array); > > > + kvm->fill_efault_info = false; > > > > > > INIT_LIST_HEAD(&kvm->gpc_list); > > > spin_lock_init(&kvm->gpc_lock); > > > @@ -4096,6 +4097,8 @@ static long kvm_vcpu_ioctl(struct file *filp, > > > put_pid(oldpid); > > > } > > > r = kvm_arch_vcpu_ioctl_run(vcpu); > > > + WARN_ON_ONCE(r == -EFAULT && > > > + vcpu->run->exit_reason != KVM_EXIT_MEMORY_FAULT); > > > > This might be a bit overkill, as it will definitely fire on unsupported > > architectures. Instead you may want to condition this on an architecture > > actually selecting support for MEMORY_FAULT_INFO. > > Ah, that's embarrassing. Thanks for the catch. No problem at all. Pretty sure I've done a lot more actually egregious changes than you have ;) While we're here, forgot to mention it before but please clean up that indentation too. I think you may've gotten in a fight with the Google3 styling of your editor and lost :) -- Thanks, Oliver
