Subject: [RFC PATCH v4 11/11] coco: guest: arm64: Enable vdev DMA after attestation

From: "Aneesh Kumar K.V (Arm)" <[email-masked]>
Date: Mon, 27 Apr 2026 13:58:05 +0530

- define SMC_RSI_VDEV_DMA_ENABLE and add wrapper in rsi_cmds.h
- invoke the new helper from the guest accept path once the device
  passes attestation, rolling back to TDI_LOCKED on failure

Reviewed-by: Jonathan Cameron <[email-masked]>
Signed-off-by: Aneesh Kumar K.V (Arm) <[email-masked]>
---
 arch/arm64/include/asm/rsi_cmds.h        | 16 ++++++++++++++++
 arch/arm64/include/asm/rsi_smc.h         |  2 ++
 drivers/virt/coco/arm-cca-guest/rsi-da.c | 14 ++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h
index f72d8e0cd422..1e0d1cd8841a 100644
--- a/arch/arm64/include/asm/rsi_cmds.h
+++ b/arch/arm64/include/asm/rsi_cmds.h
@@ -226,4 +226,20 @@ static inline unsigned long rsi_vdev_get_info(unsigned long vdev_id,
 	return res.a0;
 }
 
+static inline unsigned long __rsi_vdev_dma_enable(unsigned long vdev_id,
+						  unsigned long flags,
+						  unsigned long non_ats_plane,
+						  unsigned long lock_nonce,
+						  unsigned long meas_nonce,
+						  unsigned long report_nonce)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RSI_VDEV_DMA_ENABLE, vdev_id, flags,
+			     non_ats_plane, lock_nonce,
+			     meas_nonce, report_nonce, &res);
+
+	return res.a0;
+}
+
 #endif /* __ASM_RSI_CMDS_H */
diff --git a/arch/arm64/include/asm/rsi_smc.h b/arch/arm64/include/asm/rsi_smc.h
index 99b34b37b693..1d98a3b47c89 100644
--- a/arch/arm64/include/asm/rsi_smc.h
+++ b/arch/arm64/include/asm/rsi_smc.h
@@ -186,6 +186,8 @@ struct realm_config {
  */
 #define SMC_RSI_IPA_STATE_GET			SMC_RSI_FID(0x198)
 
+#define SMC_RSI_VDEV_DMA_ENABLE			SMC_RSI_FID(0x19C)
+
 #define RSI_VDEV_REPORT_FORMAT_TDISP 0x1
 struct rsi_vdevice_info {
 	union {
diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.c b/drivers/virt/coco/arm-cca-guest/rsi-da.c
index 7c2b28fa43a1..77267479df19 100644
--- a/drivers/virt/coco/arm-cca-guest/rsi-da.c
+++ b/drivers/virt/coco/arm-cca-guest/rsi-da.c
@@ -231,9 +231,17 @@ int cca_verify_digests(u64 hash_algo,
 	return 0;
 }
 
+static inline int rsi_vdev_enable_dma(int vdev_id, struct dsm_device_info *dev_info)
+{
+	/* No ATS support */
+	return __rsi_vdev_dma_enable(vdev_id, 0, 0, dev_info->lock_nonce,
+				     dev_info->meas_nonce, dev_info->report_nonce);
+}
+
 int cca_device_accept(struct pci_dev *pdev, unsigned long lock_nonce)
 {
 	int ret;
+	int vdev_id = rsi_vdev_id(pdev);
 	struct cca_guest_dsc *dsc = to_cca_guest_dsc(pdev);
 
 	if (lock_nonce != dsc->dev_info.lock_nonce) {
@@ -270,6 +278,12 @@ int cca_device_accept(struct pci_dev *pdev, unsigned long lock_nonce)
 		return ret;
 	}
 
+	if (rsi_vdev_enable_dma(vdev_id, &dsc->dev_info)) {
+		rhi_vdev_set_tdi_state(pdev, RHI_DA_TDI_CONFIG_LOCKED);
+		pci_err(pdev, "failed to enable DMA from the device\n");
+		return -EIO;
+	}
+
 	dsc->pci.mmio = no_free_ptr(tsm_mmio);
 	return 0;
 }
-- 
2.43.0