KVM: arm64: Plug FEAT_GCS handling

We don't seem to be handling the GCS-specific exception class.
Handle it by delivering an UNDEF to the guest, and populate the
relevant trap bits.

Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index ff75695..cc5c2ee 100644 (file)
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -298,6 +298,16 @@ static int handle_svc(struct kvm_vcpu *vcpu)
        return 1;
 }
 
+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);
+
+       kvm_inject_undefined(vcpu);
+       return 1;
+}
+
 static int handle_other(struct kvm_vcpu *vcpu)
 {
        bool is_l2 = vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu);
@@ -380,6 +390,7 @@ static exit_handle_fn arm_exit_handlers[] = {
        [ESR_ELx_EC_BRK64]      = kvm_handle_guest_debug,
        [ESR_ELx_EC_FP_ASIMD]   = kvm_handle_fpasimd,
        [ESR_ELx_EC_PAC]        = kvm_handle_ptrauth,
+       [ESR_ELx_EC_GCS]        = kvm_handle_gcs,
 };
 
 static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index ce347dd..a9ecca4 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -5209,6 +5209,14 @@ void kvm_calculate_traps(struct kvm_vcpu *vcpu)
                                                HFGITR_EL2_nBRBIALL);
        }
 
+       if (!kvm_has_feat(kvm, ID_AA64PFR1_EL1, GCS, IMP)) {
+               kvm->arch.fgu[HFGRTR_GROUP] |= (HFGRTR_EL2_nGCS_EL0 |
+                                               HFGRTR_EL2_nGCS_EL1);
+               kvm->arch.fgu[HFGITR_GROUP] |= (HFGITR_EL2_nGCSPUSHM_EL1 |
+                                               HFGITR_EL2_nGCSSTR_EL1 |
+                                               HFGITR_EL2_nGCSEPP);
+       }
+
        set_bit(KVM_ARCH_FLAG_FGU_INITIALIZED, &kvm->arch.flags);
 out:
        mutex_unlock(&kvm->arch.config_lock);