From: Christoffer Dall <[email protected]> When faulting on a shadow stage 2 page table we have to check if the fault was a permission fault and if so, if that fault needs to be handled by the guest hypervisor before us, in case the guest hypervisor has created a less permissive S2 entry than the operation required.
Check if this is the case, and inject a fault if it is. Signed-off-by: Christoffer Dall <[email protected]> Signed-off-by: Jintack Lim <[email protected]> --- arch/arm/include/asm/kvm_mmu.h | 7 +++++++ arch/arm/kvm/mmu.c | 5 +++++ arch/arm64/include/asm/kvm_mmu.h | 9 +++++++++ arch/arm64/kvm/mmu-nested.c | 33 +++++++++++++++++++++++++++++++++ 4 files changed, 54 insertions(+) diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index ab41a10..0d106ae 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -241,6 +241,13 @@ static inline int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa, return 0; } +static inline int kvm_s2_handle_perm_fault(struct kvm_vcpu *vcpu, + phys_addr_t fault_ipa, + struct kvm_s2_trans *trans) +{ + return 0; +} + static inline void kvm_nested_s2_unmap(struct kvm_vcpu *vcpu) { } static inline int kvm_nested_s2_init(struct kvm_vcpu *vcpu) { return 0; } static inline void kvm_nested_s2_teardown(struct kvm_vcpu *vcpu) { } diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index abdf345..68fc8e8 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -1542,6 +1542,11 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run) ret = kvm_walk_nested_s2(vcpu, fault_ipa, &nested_trans); if (ret) goto out_unlock; + + ret = kvm_s2_handle_perm_fault(vcpu, fault_ipa, &nested_trans); + if (ret) + goto out_unlock; + ipa = nested_trans.output; } diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 2ac603d..2086296 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -338,6 +338,8 @@ struct kvm_s2_trans { bool handle_vttbr_update(struct kvm_vcpu *vcpu, u64 vttbr); int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa, struct kvm_s2_trans *result); +int kvm_s2_handle_perm_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, + struct kvm_s2_trans *trans); void kvm_nested_s2_unmap(struct kvm_vcpu *vcpu); int kvm_nested_s2_init(struct kvm_vcpu *vcpu); void kvm_nested_s2_teardown(struct kvm_vcpu *vcpu); @@ -366,6 +368,13 @@ static inline int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa, return 0; } +static inline int kvm_s2_handle_perm_fault(struct kvm_vcpu *vcpu, + phys_addr_t fault_ipa, + struct kvm_s2_trans *trans) +{ + return 0; +} + static inline void kvm_nested_s2_unmap(struct kvm_vcpu *vcpu) { } static inline int kvm_nested_s2_init(struct kvm_vcpu *vcpu) { return 0; } static inline void kvm_nested_s2_teardown(struct kvm_vcpu *vcpu) { } diff --git a/arch/arm64/kvm/mmu-nested.c b/arch/arm64/kvm/mmu-nested.c index b579d23..65ad0da 100644 --- a/arch/arm64/kvm/mmu-nested.c +++ b/arch/arm64/kvm/mmu-nested.c @@ -52,6 +52,19 @@ static unsigned int pa_max(void) return ps_to_output_size(parange); } +static int vcpu_inject_s2_perm_fault(struct kvm_vcpu *vcpu, gpa_t ipa, + int level) +{ + u32 esr; + + vcpu->arch.ctxt.el2_regs[FAR_EL2] = vcpu->arch.fault.far_el2; + vcpu->arch.ctxt.el2_regs[HPFAR_EL2] = vcpu->arch.fault.hpfar_el2; + esr = kvm_vcpu_get_hsr(vcpu) & ~ESR_ELx_FSC; + esr |= ESR_ELx_FSC_PERM; + esr |= level & 0x3; + return kvm_inject_nested_sync(vcpu, esr); +} + static int vcpu_inject_s2_trans_fault(struct kvm_vcpu *vcpu, gpa_t ipa, int level) { @@ -268,6 +281,26 @@ int kvm_walk_nested_s2(struct kvm_vcpu *vcpu, phys_addr_t gipa, return walk_nested_s2_pgd(vcpu, gipa, &wi, result); } +/* + * Returns non-zero if permission fault is handled by injecting it to the next + * level hypervisor. + */ +int kvm_s2_handle_perm_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, + struct kvm_s2_trans *trans) +{ + unsigned long fault_status = kvm_vcpu_trap_get_fault_type(vcpu); + bool write_fault = kvm_is_write_fault(vcpu); + + if (fault_status != FSC_PERM) + return 0; + + if ((write_fault && !trans->writable) || + (!write_fault && !trans->readable)) + return vcpu_inject_s2_perm_fault(vcpu, fault_ipa, trans->level); + + return 0; +} + /* expects kvm->mmu_lock to be held */ void kvm_nested_s2_all_vcpus_wp(struct kvm *kvm) { -- 1.9.1 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
