From: Fuad Tabba <tabba@xxxxxxxxxx> Do not rely on the state of the vm as provided by the host, but initialize it instead at EL2 to a known good and safe state. Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx> --- arch/arm64/kvm/hyp/nvhe/pkvm.c | 71 ++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 839506a546c7..51da5c1d7e0d 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -6,6 +6,9 @@ #include <linux/kvm_host.h> #include <linux/mm.h> + +#include <asm/kvm_emulate.h> + #include <nvhe/mem_protect.h> #include <nvhe/memory.h> #include <nvhe/pkvm.h> @@ -315,6 +318,53 @@ struct kvm_shadow_vcpu_state *pkvm_loaded_shadow_vcpu_state(void) return __this_cpu_read(loaded_shadow_state); } +/* Check and copy the supported features for the vcpu from the host. */ +static void copy_features(struct kvm_vcpu *shadow_vcpu, struct kvm_vcpu *host_vcpu) +{ + DECLARE_BITMAP(allowed_features, KVM_VCPU_MAX_FEATURES); + + /* No restrictions for non-protected VMs. */ + if (!kvm_vm_is_protected(shadow_vcpu->kvm)) { + bitmap_copy(shadow_vcpu->arch.features, + host_vcpu->arch.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_PMUVER), PVM_ID_AA64DFR0_ALLOW)) + set_bit(KVM_ARM_VCPU_PMU_V3, allowed_features); + + if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_SVE), PVM_ID_AA64PFR0_ALLOW)) + set_bit(KVM_ARM_VCPU_SVE, allowed_features); + + if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_API), PVM_ID_AA64ISAR1_ALLOW) && + FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_APA), PVM_ID_AA64ISAR1_ALLOW)) + set_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, allowed_features); + + if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_GPI), PVM_ID_AA64ISAR1_ALLOW) && + FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_GPA), PVM_ID_AA64ISAR1_ALLOW)) + set_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, allowed_features); + + bitmap_and(shadow_vcpu->arch.features, host_vcpu->arch.features, + allowed_features, KVM_VCPU_MAX_FEATURES); +} + static void unpin_host_vcpus(struct kvm_shadow_vcpu_state *shadow_vcpu_states, unsigned int nr_vcpus) { @@ -350,6 +400,17 @@ static int set_host_vcpus(struct kvm_shadow_vcpu_state *shadow_vcpu_states, return 0; } +static int init_ptrauth(struct kvm_vcpu *shadow_vcpu) +{ + int ret = 0; + + if (test_bit(KVM_ARM_VCPU_PTRAUTH_ADDRESS, shadow_vcpu->arch.features) || + test_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, shadow_vcpu->arch.features)) + ret = kvm_vcpu_enable_ptrauth(shadow_vcpu); + + return ret; +} + static int init_shadow_structs(struct kvm *kvm, struct kvm_shadow_vm *vm, struct kvm_vcpu **vcpu_array, int *last_ran, @@ -357,10 +418,12 @@ static int init_shadow_structs(struct kvm *kvm, struct kvm_shadow_vm *vm, unsigned int nr_vcpus) { int i; + int ret; vm->host_kvm = kvm; vm->kvm.created_vcpus = nr_vcpus; vm->kvm.arch.vtcr = host_kvm.arch.vtcr; + vm->kvm.arch.pkvm.enabled = READ_ONCE(kvm->arch.pkvm.enabled); vm->kvm.arch.mmu.last_vcpu_ran = last_ran; vm->last_ran_size = last_ran_size; memset(vm->kvm.arch.mmu.last_vcpu_ran, -1, sizeof(int) * hyp_nr_cpus); @@ -377,8 +440,16 @@ static int init_shadow_structs(struct kvm *kvm, struct kvm_shadow_vm *vm, shadow_vcpu->vcpu_idx = i; shadow_vcpu->arch.hw_mmu = &vm->kvm.arch.mmu; + shadow_vcpu->arch.power_off = true; + + copy_features(shadow_vcpu, host_vcpu); + + ret = init_ptrauth(shadow_vcpu); + if (ret) + return ret; pkvm_vcpu_init_traps(shadow_vcpu, host_vcpu); + kvm_reset_pvm_sys_regs(shadow_vcpu); } return 0; -- 2.36.1.124.g0e6072fb45-goog