ANDROID: KVM: arm64: Add request_dma guest HVC

Add request_dma HVC which returns 128 bit token to authenticate a
pvIOMMU and vsid pair.

Bug: 357781595
Bug: 348382247
Bug: 236685427
Change-Id: If032cf3e14653c0114aec3595902d09d6b3fded2
Signed-off-by: Mostafa Saleh <smostafa@google.com>

arch/arm64/kvm/hyp/include/nvhe/iommu.h

@@ -48,6 +48,7 @@ int kvm_iommu_snapshot_host_stage2(struct kvm_hyp_iommu_domain *domain);
 int kvm_iommu_dev_block_dma(pkvm_handle_t iommu_id, u32 endpoint_id, bool host_to_guest);
 
 int kvm_iommu_force_free_domain(pkvm_handle_t domain_id, struct pkvm_hyp_vm *vm);
+int kvm_iommu_id_to_token(pkvm_handle_t smmu_id, u64 *out_token);
 
 struct kvm_iommu_ops {
 	int (*init)(void);
@@ -75,6 +76,7 @@ struct kvm_iommu_ops {
 	int (*resume)(struct kvm_hyp_iommu *iommu);
 	int (*dev_block_dma)(struct kvm_hyp_iommu *iommu, u32 endpoint_id,
 			     bool is_host_to_guest);
+	int (*get_iommu_token_by_id)(pkvm_handle_t smmu_id, u64 *out_token);
 	ANDROID_KABI_RESERVE(1);
 	ANDROID_KABI_RESERVE(2);
 	ANDROID_KABI_RESERVE(3);

arch/arm64/kvm/hyp/include/nvhe/pkvm.h

@@ -184,6 +184,7 @@ int pkvm_init_scmi_pd(struct kvm_power_domain *pd,
 		      const struct kvm_power_domain_ops *ops);
 
 bool pkvm_device_request_mmio(struct pkvm_hyp_vcpu *hyp_vcpu, u64 *exit_code);
+bool pkvm_device_request_dma(struct pkvm_hyp_vcpu *hyp_vcpu, u64 *exit_code);
 void pkvm_devices_teardown(struct pkvm_hyp_vm *vm);
 int pkvm_devices_get_context(u64 iommu_id, u32 endpoint_id, struct pkvm_hyp_vm *vm);
 void pkvm_devices_put_context(u64 iommu_id, u32 endpoint_id);

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

@@ -8,6 +8,7 @@
 #include <nvhe/mem_protect.h>
 #include <nvhe/mm.h>
 #include <nvhe/pkvm.h>
+#include <nvhe/pviommu-host.h>
 
 #include <kvm/arm_hypercalls.h>
 #include <kvm/device.h>
@@ -419,3 +420,56 @@ int pkvm_device_register_reset(u64 phys, void *cookie,
 
 	return ret;
 }
+
+bool pkvm_device_request_dma(struct pkvm_hyp_vcpu *hyp_vcpu, u64 *exit_code)
+{
+	int ret;
+	struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(hyp_vcpu);
+	struct kvm_vcpu *vcpu = &hyp_vcpu->vcpu;
+	u64 pviommu = smccc_get_arg1(vcpu);
+	u64 vsid = smccc_get_arg2(vcpu);
+	u64 token1, token2;
+	struct pviommu_route route;
+	struct pkvm_device *dev;
+
+	if (smccc_get_arg3(vcpu) || smccc_get_arg4(vcpu) || smccc_get_arg5(vcpu) ||
+	    smccc_get_arg6(vcpu))
+		goto out_ret;
+
+	ret = pkvm_pviommu_get_route(vm, pviommu, vsid, &route);
+	if (ret)
+		goto out_ret;
+	token2 = route.sid;
+	/*
+	 * route.iommu is the host-hyp iommu ID that has no meaning for guest.
+	 * It needs to be converted to IOMMU token as in the firmware(usually
+	 * base MMIO address).
+	 */
+	ret = kvm_iommu_id_to_token(route.iommu, &token1);
+	if (ret)
+		goto out_ret;
+
+	dev = pkvm_get_device_by_iommu(route.iommu, route.sid);
+	if (!dev)
+		goto out_ret;
+
+	hyp_spin_lock(&device_spinlock);
+	if (dev->ctxt == NULL) {
+		/*
+		 * First time device is assigned to guest, make sure it's resources
+		 * have been donated.
+		 */
+		ret = __pkvm_group_assign(dev->group_id, vm);
+	} else if (dev->ctxt != vm) {
+		ret = -EPERM;
+	}
+	hyp_spin_unlock(&device_spinlock);
+	if (ret)
+		goto out_ret;
+
+	smccc_set_retval(vcpu, SMCCC_RET_SUCCESS, token1, token2, 0);
+	return true;
+out_ret:
+	smccc_set_retval(vcpu, SMCCC_RET_INVALID_PARAMETER, 0, 0, 0);
+	return true;
+}

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

@@ -778,3 +778,10 @@ int kvm_iommu_snapshot_host_stage2(struct kvm_hyp_iommu_domain *domain)
 
 	return ret;
 }
+
+int kvm_iommu_id_to_token(pkvm_handle_t id, u64 *out_token)
+{
+	if (!kvm_iommu_ops || !kvm_iommu_ops->get_iommu_token_by_id)
+		return -ENODEV;
+	return kvm_iommu_ops->get_iommu_token_by_id(id, out_token);
+}

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

@@ -1759,6 +1759,8 @@ bool kvm_handle_pvm_hvc64(struct kvm_vcpu *vcpu, u64 *exit_code)
 		return kvm_handle_pviommu_hvc(vcpu, exit_code);
 	case ARM_SMCCC_VENDOR_HYP_KVM_DEV_REQ_MMIO_FUNC_ID:
 		return pkvm_device_request_mmio(hyp_vcpu, exit_code);
+	case ARM_SMCCC_VENDOR_HYP_KVM_DEV_REQ_DMA_FUNC_ID:
+		return pkvm_device_request_dma(hyp_vcpu, exit_code);
 	default:
 		if (is_ffa_call(fn))
 			return kvm_guest_ffa_handler(hyp_vcpu, exit_code);

drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c

@@ -1546,6 +1546,16 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
 	return true;
 }
 
+static int smmu_id_to_token(pkvm_handle_t smmu_id, u64 *out_token)
+{
+	if (smmu_id >= kvm_hyp_arm_smmu_v3_count)
+		return -EINVAL;
+
+	smmu_id = array_index_nospec(smmu_id, kvm_hyp_arm_smmu_v3_count);
+	*out_token = kvm_hyp_arm_smmu_v3_smmus[smmu_id].mmio_addr;
+	return 0;
+}
+
 static int smmu_dev_block_dma(struct kvm_hyp_iommu *iommu, u32 sid, bool is_host2guest)
 {
 	struct hyp_arm_smmu_v3_device *smmu = to_smmu(iommu);
@@ -1730,4 +1740,5 @@ struct kvm_iommu_ops smmu_ops = {
 	.resume				= smmu_resume,
 	.host_stage2_idmap		= smmu_host_stage2_idmap,
 	.dev_block_dma			= smmu_dev_block_dma,
+	.get_iommu_token_by_id		= smmu_id_to_token,
 };

include/linux/arm-smccc.h

@@ -182,7 +182,7 @@
 #define ARM_SMCCC_KVM_FUNC_PKVM_RESV_58		58
 #define ARM_SMCCC_KVM_FUNC_PKVM_RESV_59		59
 #define ARM_SMCCC_KVM_FUNC_PKVM_RESV_60		60
-#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_61		61
+#define ARM_SMCCC_KVM_FUNC_DEV_REQ_DMA		61
 #define ARM_SMCCC_KVM_FUNC_PVIOMMU_OP		62
 #define ARM_SMCCC_KVM_FUNC_DEV_REQ_MMIO		63
 /* End of pKVM hypercall range */
@@ -253,6 +253,12 @@
 			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
 			   ARM_SMCCC_KVM_FUNC_DEV_REQ_MMIO)
 
+#define ARM_SMCCC_VENDOR_HYP_KVM_DEV_REQ_DMA_FUNC_ID			\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
+			   ARM_SMCCC_SMC_64,				\
+			   ARM_SMCCC_OWNER_VENDOR_HYP,			\
+			   ARM_SMCCC_KVM_FUNC_DEV_REQ_DMA)
+
 /* ptp_kvm counter type ID */
 #define KVM_PTP_VIRT_COUNTER			0
 #define KVM_PTP_PHYS_COUNTER			1