Start folding the guest hypervisor's FP/SVE traps into the value programmed in hardware. Note that as of writing this is dead code, since KVM does a full put() / load() for every nested exception boundary which saves + flushes the FP/SVE state. However, this will become useful when we can keep the guest's FP/SVE state alive across a nested exception boundary and the host no longer needs to conservatively program traps. Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx> --- arch/arm64/kvm/hyp/vhe/switch.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 697253673d7b..d07b4f4be5e5 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -85,6 +85,19 @@ static void __activate_cptr_traps(struct kvm_vcpu *vcpu) __activate_traps_fpsimd32(vcpu); } + /* + * Layer the guest hypervisor's trap configuration on top of our own if + * we're in a nested context. + */ + if (!vcpu_has_nv(vcpu) || is_hyp_ctxt(vcpu)) + goto write; + + if (guest_hyp_fpsimd_traps_enabled(vcpu)) + val &= ~CPACR_ELx_FPEN; + if (guest_hyp_sve_traps_enabled(vcpu)) + val &= ~CPACR_ELx_ZEN; + +write: write_sysreg(val, cpacr_el1); } -- 2.45.1.288.g0e0cd299f1-goog
