On Thu, 21 Apr 2022 16:22:00 +0100, Alexandru Elisei <alexandru.elisei@xxxxxxx> wrote: > > Hi, > > On Thu, Apr 21, 2022 at 01:58:52PM +0100, Marc Zyngier wrote: > > On Thu, 21 Apr 2022 11:05:47 +0100, > > Alexandru Elisei <alexandru.elisei@xxxxxxx> wrote: > > > > > > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > > > index 93d92130d36c..fd5b6773e3a2 100644 > > > --- a/arch/arm64/kvm/handle_exit.c > > > +++ b/arch/arm64/kvm/handle_exit.c > > > @@ -121,6 +121,8 @@ static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu) > > > > > > run->exit_reason = KVM_EXIT_DEBUG; > > > run->debug.arch.hsr = lower_32_bits(esr); > > > + run->debug.arch.hsr_high = upper_32_bits(esr); > > > + run->flags |= KVM_DEBUG_ARCH_HSR_HIGH_VALID; > > > > Who will eventually clear this flag? I'm concerned that it could be > > misinterpreted by other userspace paths, as once you get a debug exit > > on this vcpu, it will always be set. > > > > Probably only a matter of clearing flags on all the other exit paths. > > I missed this part, I was under the impression that kvm_run->flags was > already cleared on every exit (that's why it's bitwise OR'ed with the > flag). > > kvm_arch_vcpu_ioctl_run() always sets exit_reason = KVM_EXIT_UNKNOWN, so I > guess if we want to be consistent, kvm_run->flags should be cleared at the > same time. Unless you want KVM to clear flags for all exit reasons *except* > KVM_EXIT_UNKNOWN. > > I prefer clearing flags in kvm_arch_vcpu_ioctl_run() as that looks to me > like the least error prone way to do it, and if in the future an exit > reason wants to preserve flags across KVM_RUN ioctls we can add a check for > that particular situation. It seems entirely reasonable to reset exit_reason and flags together. > > > > > Also, please document the flag in the API file (only a couple of x86 > > flags are there so far). > > Sure thing, will do. Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
