On Tue, Sep 01, 2026 at 10:47:05PM +0100, Mark Brown wrote: > For nested guests where HFGITR_EL2.nGCSSTR_EL1 is clear or when there are > L2 GCS data check exceptions we need to forward the exception to the guest. > Add handling to do so. > > Signed-off-by: Mark Brown <[email protected]> > --- > arch/arm64/kvm/handle_exit.c | 18 +++++++++++++++--- > 1 file changed, 15 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index db37678dcb05..a8198e96fcb4 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -304,12 +304,24 @@ static int handle_svc(struct kvm_vcpu *vcpu) > return 1; > } > > +/* > + * We might get GCS exceptions that need to be forwarded to the > + * hypervisor when a nested guest has HFGITR_EL2.nGCSSTR_EL1 clear, or > + * for a GCS data check exception for a L2 guest. > + */ > static int kvm_handle_gcs(struct kvm_vcpu *vcpu) > { > - /* We don't expect GCS, so treat it with contempt */ > - if (kvm_has_feat(vcpu->kvm, ID_AA64PFR1_EL1, GCS, IMP)) > - WARN_ON_ONCE(1); > + if (!kvm_has_gcs(vcpu->kvm)) { > + kvm_inject_undefined(vcpu); > + return 1; > + } > > + if (vcpu_has_nv(vcpu)) { > + kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu)); > + return 1; > + } > + > + WARN_ON_ONCE(1); > kvm_inject_undefined(vcpu); > return 1; > }
Oh handle_gcs, if kvm_has_gcs() && kvm_has_nv() -> Inject synchronous exception. Makes sense. (it kept bothering me that the !gcs and the gcs case do the same thing, except for a warn_once. So I thougt on suggesting: + if (!kvm_has_gcs(vcpu->kvm)) + goto inject_undef; [...] + WARN_ON_ONCE(1); +inject_undef: > kvm_inject_undefined(vcpu); > return 1; But after it was done it did not look better.) So, FWIW: Reviewed-by: Leonardo Bras <[email protected]> Thanks! Leo
