Add a bit of infrastrtcture to triage_sysreg_trap() to handle the case of registers falling into the Feature ID space that do not have a local handler. For these, we can directly apply the FEAT_IDST semantics and inject an EC=0x18 exception. Otherwise, an UNDEF will do. Reviewed-by: Joey Gouly Reviewed-by: Yuan Yao Signed-off-by: Marc Zyngier --- arch/arm64/kvm/emulate-nested.c | 13 +++++++++++++ arch/arm64/kvm/sys_regs.h | 10 ++++++++++ 2 files changed, 23 insertions(+) diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c index 616eb6ad68701..4aabd624c4be5 100644 --- a/arch/arm64/kvm/emulate-nested.c +++ b/arch/arm64/kvm/emulate-nested.c @@ -2588,6 +2588,19 @@ bool triage_sysreg_trap(struct kvm_vcpu *vcpu, int *sr_index) params = esr_sys64_to_params(esr); + /* + * This implements the pseudocode UnimplementedIDRegister() + * helper for the purpose of dealing with FEAT_IDST. + */ + if (in_feat_id_space(¶ms)) { + if (kvm_has_feat(vcpu->kvm, ID_AA64MMFR2_EL1, IDS, IMP)) + kvm_inject_sync(vcpu, kvm_vcpu_get_esr(vcpu)); + else + kvm_inject_undefined(vcpu); + + return true; + } + /* * Check for the IMPDEF range, as per DDI0487 J.a, * D18.3.2 Reserved encodings for IMPLEMENTATION diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h index b3f904472fac5..2a983664220ce 100644 --- a/arch/arm64/kvm/sys_regs.h +++ b/arch/arm64/kvm/sys_regs.h @@ -49,6 +49,16 @@ struct sys_reg_params { .Op2 = ((esr) >> 17) & 0x7, \ .is_write = !((esr) & 1) }) +/* + * The Feature ID space is defined as the System register space in AArch64 + * with op0==3, op1=={0, 1, 3}, CRn==0, CRm=={0-7}, op2=={0-7}. + */ +static inline bool in_feat_id_space(struct sys_reg_params *p) +{ + return (p->Op0 == 3 && !(p->Op1 & 0b100) && p->Op1 != 2 && + p->CRn == 0 && !(p->CRm & 0b1000)); +} + struct sys_reg_desc { /* Sysreg string for debug */ const char *name; -- 2.47.3