ANDROID: KVM: arm64: Introduce KVM_CAP_ARM_PROTECTED_VM to set/query PVM firmware

Expose a new capability, KVM_CAP_ARM_PROTECTED_VM, for protected VMs
which allows the size of the PVM firmware region to be discovered from
userspace and for the firmware load address to be specified if it is
required.

Signed-off-by: Will Deacon <will@kernel.org>
Bug: 209580772
Change-Id: I819b9b2cfa227f1a0607a8f683aa01d4ae50704f
Signed-off-by: Will Deacon <willdeacon@google.com>

arch/arm64/include/asm/kvm_pkvm.h

@@ -17,6 +17,7 @@
 #define HYP_MEMBLOCK_REGIONS 128
 #define PVMFW_INVALID_LOAD_ADDR	(-1)
 
+int kvm_arm_vm_ioctl_pkvm(struct kvm *kvm, struct kvm_enable_cap *cap);
 int kvm_init_pvm(struct kvm *kvm, unsigned long type);
 int create_el2_shadow(struct kvm *kvm);
 

arch/arm64/include/uapi/asm/kvm.h

@@ -413,6 +413,15 @@ struct kvm_arm_copy_mte_tags {
 #define KVM_PSCI_RET_INVAL		PSCI_RET_INVALID_PARAMS
 #define KVM_PSCI_RET_DENIED		PSCI_RET_DENIED
 
+/* Protected KVM */
+#define KVM_CAP_ARM_PROTECTED_VM_FLAGS_SET_FW_IPA	0
+#define KVM_CAP_ARM_PROTECTED_VM_FLAGS_INFO		1
+
+struct kvm_protected_vm_info {
+	__u64 firmware_size;
+	__u64 __reserved[7];
+};
+
 #endif
 
 #endif /* __ARM_KVM_H__ */

arch/arm64/kvm/arm.c

@@ -88,9 +88,16 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 {
 	int r;
 
-	if (cap->flags)
-		return -EINVAL;
+	/* Capabilities with flags */
+	switch (cap->cap) {
+	case KVM_CAP_ARM_PROTECTED_VM:
+		return kvm_arm_vm_ioctl_pkvm(kvm, cap);
+	default:
+		if (cap->flags)
+			return -EINVAL;
+	}
 
+	/* Capabilities without flags */
 	switch (cap->cap) {
 	case KVM_CAP_ARM_NISV_TO_USER:
 		r = 0;
@@ -107,9 +114,6 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 		mutex_unlock(&kvm->lock);
 		break;
 	case KVM_CAP_EXIT_HYPERCALL:
-		if (cap->flags)
-			return -EINVAL;
-
 		if (cap->args[0] & ~KVM_EXIT_HYPERCALL_VALID_MASK)
 			return -EINVAL;
 
@@ -390,6 +394,9 @@ static int pkvm_check_extension(struct kvm *kvm, long ext, int kvm_cap)
 		    FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR1_GPA),
 			      PVM_ID_AA64ISAR1_ALLOW);
 		break;
+	case KVM_CAP_ARM_PROTECTED_VM:
+		r = 1;
+		break;
 	default:
 		r = 0;
 		break;

arch/arm64/kvm/hyp/nvhe/pkvm.c

@@ -356,7 +356,7 @@ static int init_shadow_structs(struct kvm *kvm, struct kvm_shadow_vm *vm, int nr
 
 	vm->host_kvm = kvm;
 	vm->created_vcpus = 0;
-	vm->arch.pkvm.pvmfw_load_addr = PVMFW_INVALID_LOAD_ADDR;
+	vm->arch.pkvm.pvmfw_load_addr = kvm->arch.pkvm.pvmfw_load_addr;
 
 	for (i = 0; i < nr_vcpus; i++) {
 		struct kvm_vcpu *host_vcpu = kern_hyp_va(kvm->vcpus[i]);

arch/arm64/kvm/pkvm.c

@@ -245,6 +245,54 @@ static int __init pkvm_firmware_rmem_clear(void)
 }
 device_initcall_sync(pkvm_firmware_rmem_clear);
 
+static int pkvm_vm_ioctl_set_fw_ipa(struct kvm *kvm, u64 ipa)
+{
+	int ret = 0;
+
+	if (!pkvm_firmware_mem)
+		return -EINVAL;
+
+	mutex_lock(&kvm->arch.pkvm.shadow_lock);
+	if (kvm->arch.pkvm.shadow_handle) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
+	kvm->arch.pkvm.pvmfw_load_addr = ipa;
+out_unlock:
+	mutex_unlock(&kvm->arch.pkvm.shadow_lock);
+	return ret;
+}
+
+static int pkvm_vm_ioctl_info(struct kvm *kvm,
+			      struct kvm_protected_vm_info __user *info)
+{
+	struct kvm_protected_vm_info kinfo = {
+		.firmware_size = pkvm_firmware_mem ?
+				 pkvm_firmware_mem->size :
+				 0,
+	};
+
+	return copy_to_user(info, &kinfo, sizeof(kinfo)) ? -EFAULT : 0;
+}
+
+int kvm_arm_vm_ioctl_pkvm(struct kvm *kvm, struct kvm_enable_cap *cap)
+{
+	if (cap->args[1] || cap->args[2] || cap->args[3])
+		return -EINVAL;
+
+	switch (cap->flags) {
+	case KVM_CAP_ARM_PROTECTED_VM_FLAGS_SET_FW_IPA:
+		return pkvm_vm_ioctl_set_fw_ipa(kvm, cap->args[0]);
+	case KVM_CAP_ARM_PROTECTED_VM_FLAGS_INFO:
+		return pkvm_vm_ioctl_info(kvm, (void __force __user *)cap->args[0]);
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 int kvm_init_pvm(struct kvm *kvm, unsigned long type)
 {
 	mutex_init(&kvm->arch.pkvm.shadow_lock);