From cb0c272acebdf099431c34972963377f83872a08 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Fri, 18 Oct 2024 08:48:31 +0100 Subject: [PATCH] KVM: arm64: Initialize the hypervisor's VM state at EL2 Do not trust the state of the VM as provided by the host when initializing the hypervisor's view of the VM sate. Initialize it instead at EL2 to a known good and safe state, as pKVM already does with hypervisor VCPU states. Signed-off-by: Fuad Tabba Link: https://lore.kernel.org/r/20241018074833.2563674-4-tabba@google.com Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/nvhe/pkvm.c | 77 ++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 869955e551a05..954df57a935f5 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -6,6 +6,9 @@ #include #include + +#include + #include #include #include @@ -289,6 +292,65 @@ void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu) hyp_spin_unlock(&vm_table_lock); } +static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struct kvm *host_kvm) +{ + struct kvm *kvm = &hyp_vm->kvm; + DECLARE_BITMAP(allowed_features, KVM_VCPU_MAX_FEATURES); + + /* No restrictions for non-protected VMs. */ + if (!kvm_vm_is_protected(kvm)) { + bitmap_copy(kvm->arch.vcpu_features, + host_kvm->arch.vcpu_features, + KVM_VCPU_MAX_FEATURES); + return; + } + + bitmap_zero(allowed_features, KVM_VCPU_MAX_FEATURES); + + /* + * For protected VMs, always allow: + * - CPU starting in poweroff state + * - PSCI v0.2 + */ + set_bit(KVM_ARM_VCPU_POWER_OFF, allowed_features); + set_bit(KVM_ARM_VCPU_PSCI_0_2, allowed_features); + + /* + * Check if remaining features are allowed: + * - Performance Monitoring + * - Scalable Vectors + * - Pointer Authentication + */ + if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), PVM_ID_AA64DFR0_ALLOW)) + set_bit(KVM_ARM_VCPU_PMU_V3, allowed_features); + + if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE), PVM_ID_AA64PFR0_ALLOW)) + set_bit(KVM_ARM_VCPU_SVE, allowed_features); + + if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_API), PVM_ID_AA64ISAR1_RESTRICT_UNSIGNED) && + FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_APA), PVM_ID_AA64ISAR1_RESTRICT_UNSIGNED)) + set_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, allowed_features); + + if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPI), PVM_ID_AA64ISAR1_ALLOW) && + FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_EL1_GPA), PVM_ID_AA64ISAR1_ALLOW)) + set_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, allowed_features); + + bitmap_and(kvm->arch.vcpu_features, host_kvm->arch.vcpu_features, + allowed_features, KVM_VCPU_MAX_FEATURES); +} + +static void pkvm_vcpu_init_ptrauth(struct pkvm_hyp_vcpu *hyp_vcpu) +{ + struct kvm_vcpu *vcpu = &hyp_vcpu->vcpu; + + if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_ADDRESS) || + vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_GENERIC)) { + kvm_vcpu_enable_ptrauth(vcpu); + } else { + vcpu_clear_flag(&hyp_vcpu->vcpu, GUEST_HAS_PTRAUTH); + } +} + static void unpin_host_vcpu(struct kvm_vcpu *host_vcpu) { if (host_vcpu) @@ -310,6 +372,18 @@ static void init_pkvm_hyp_vm(struct kvm *host_kvm, struct pkvm_hyp_vm *hyp_vm, hyp_vm->host_kvm = host_kvm; hyp_vm->kvm.created_vcpus = nr_vcpus; hyp_vm->kvm.arch.mmu.vtcr = host_mmu.arch.mmu.vtcr; + hyp_vm->kvm.arch.pkvm.enabled = READ_ONCE(host_kvm->arch.pkvm.enabled); + pkvm_init_features_from_host(hyp_vm, host_kvm); +} + +static void pkvm_vcpu_init_sve(struct pkvm_hyp_vcpu *hyp_vcpu, struct kvm_vcpu *host_vcpu) +{ + struct kvm_vcpu *vcpu = &hyp_vcpu->vcpu; + + if (!vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) { + vcpu_clear_flag(vcpu, GUEST_HAS_SVE); + vcpu_clear_flag(vcpu, VCPU_SVE_FINALIZED); + } } static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu, @@ -335,7 +409,10 @@ static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu, hyp_vcpu->vcpu.arch.hw_mmu = &hyp_vm->kvm.arch.mmu; hyp_vcpu->vcpu.arch.cflags = READ_ONCE(host_vcpu->arch.cflags); + hyp_vcpu->vcpu.arch.mp_state.mp_state = KVM_MP_STATE_STOPPED; + pkvm_vcpu_init_sve(hyp_vcpu, host_vcpu); + pkvm_vcpu_init_ptrauth(hyp_vcpu); pkvm_vcpu_init_traps(&hyp_vcpu->vcpu); done: if (ret) -- 2.50.1