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
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