We rely on cpufeature framework to detect and enable CNP so for KVM we need to patch hyp to set CNP bit just before TTBR0_EL2 gets written. For the guest it is enough to update VTTBR_EL2 with CNP bit just before it gets scheduled.
Signed-off-by: Vladimir Murzin <[email protected]> --- arch/arm64/kvm/hyp-init.S | 4 ++++ arch/arm64/kvm/hyp/switch.c | 6 +++++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S index 3f96155..4fd31b3 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -63,6 +63,10 @@ __do_hyp_init: cmp x0, #HVC_STUB_HCALL_NR b.lo __kvm_handle_stub_hvc +alternative_if ARM64_HAS_CNP + orr x0, x0, #TTBR_CNP_BIT +alternative_else_nop_endif + msr ttbr0_el2, x0 mrs x4, tcr_el1 diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 945e79c..a1f3bf2 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -150,7 +150,11 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu) { struct kvm *kvm = kern_hyp_va(vcpu->kvm); - write_sysreg(kvm->arch.vttbr, vttbr_el2); + u64 val = kvm->arch.vttbr; + + if (system_supports_cnp()) + val |= TTBR_CNP_BIT; + write_sysreg(val, vttbr_el2); } static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu) -- 2.0.0 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
