From: Marc Zyngier Date: Thu, 20 Jun 2024 16:46:51 +0000 (+0000) Subject: KVM: arm64: nv: Add additional trap setup for CPTR_EL2 X-Git-Tag: v6.11-rc1~89^2~17^2~2^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cd931bd6093cb7da7b9787f04b21bca58c494537;p=thirdparty%2Flinux.git KVM: arm64: nv: Add additional trap setup for CPTR_EL2 We need to teach KVM a couple of new tricks. CPTR_EL2 and its VHE accessor CPACR_EL1 need to be handled specially: - CPACR_EL1 is trapped on VHE so that we can track the TCPAC and TTA bits - CPTR_EL2.{TCPAC,E0POE} are propagated from L1 to L2 Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20240620164653.1130714-15-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index fa6c27b6ad995..f680182971145 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -87,11 +87,23 @@ static void __activate_cptr_traps(struct kvm_vcpu *vcpu) __activate_traps_fpsimd32(vcpu); } + if (!vcpu_has_nv(vcpu)) + goto write; + + /* + * The architecture is a bit crap (what a surprise): an EL2 guest + * writing to CPTR_EL2 via CPACR_EL1 can't set any of TCPAC or TTA, + * as they are RES0 in the guest's view. To work around it, trap the + * sucker using the very same bit it can't set... + */ + if (vcpu_el2_e2h_is_set(vcpu) && is_hyp_ctxt(vcpu)) + val |= CPTR_EL2_TCPAC; + /* * 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)) + if (is_hyp_ctxt(vcpu)) goto write; cptr = vcpu_sanitised_cptr_el2(vcpu); @@ -115,6 +127,11 @@ static void __activate_cptr_traps(struct kvm_vcpu *vcpu) if (!(SYS_FIELD_GET(CPACR_ELx, ZEN, cptr) & BIT(0))) val &= ~CPACR_ELx_ZEN; + if (kvm_has_feat(vcpu->kvm, ID_AA64MMFR3_EL1, S2POE, IMP)) + val |= cptr & CPACR_ELx_E0POE; + + val |= cptr & CPTR_EL2_TCPAC; + write: write_sysreg(val, cpacr_el1); }