linux-kernel - [PATCH v2 11/11] coco: guest: arm64: Enable vdev DMA after attestation

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Message-ID: <20251117140007.122062-12-aneesh.kumar@kernel.org>
Date: Mon, 17 Nov 2025 19:30:07 +0530
From: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@...nel.org>
To: linux-coco@...ts.linux.dev,
	kvmarm@...ts.linux.dev
Cc: linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	dan.j.williams@...el.com,
	aik@....com,
	lukas@...ner.de,
	Samuel Ortiz <sameo@...osinc.com>,
	Xu Yilun <yilun.xu@...ux.intel.com>,
	Jason Gunthorpe <jgg@...pe.ca>,
	Suzuki K Poulose <Suzuki.Poulose@....com>,
	Steven Price <steven.price@....com>,
	Bjorn Helgaas <helgaas@...nel.org>,
	Jonathan Cameron <Jonathan.Cameron@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Marc Zyngier <maz@...nel.org>,
	Will Deacon <will@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>,
	"Aneesh Kumar K.V (Arm)" <aneesh.kumar@...nel.org>
Subject: [PATCH v2 11/11] coco: guest: arm64: Enable vdev DMA after attestation

- 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

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@...nel.org>
---
 arch/arm64/include/asm/rsi_cmds.h        | 15 +++++++++++++++
 arch/arm64/include/asm/rsi_smc.h         |  2 ++
 drivers/virt/coco/arm-cca-guest/rsi-da.c | 14 ++++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h
index e6d68760a729..bce08778c799 100644
--- a/arch/arm64/include/asm/rsi_cmds.h
+++ b/arch/arm64/include/asm/rsi_cmds.h
@@ -225,4 +225,19 @@ 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 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,
+			     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 49334d07dd55..7bfc8bc5c2ff 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)
+
 struct rsi_vdevice_info {
 	union {
 		struct {
diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.c b/drivers/virt/coco/arm-cca-guest/rsi-da.c
index 4852a03dd17d..0b98f6271da6 100644
--- a/drivers/virt/coco/arm-cca-guest/rsi-da.c
+++ b/drivers/virt/coco/arm-cca-guest/rsi-da.c
@@ -264,6 +264,13 @@ static int verify_digests(struct cca_guest_dsc *dsc)
 	return 0;
 }
 
+static inline int rsi_vdev_enable_dma(int vdev_id, struct dsm_device_info *dev_info)
+{
+	return __rsi_vdev_dma_enable(vdev_id, 0, dev_info->lock_nonce,
+				     dev_info->meas_nonce, dev_info->report_nonce);
+
+}
+
 int cca_device_verify_and_accept(struct pci_dev *pdev)
 {
 	int ret;
@@ -336,5 +343,12 @@ int cca_device_verify_and_accept(struct pci_dev *pdev)
 		pci_err(pdev, "failed to switch the device (%u) to RUN state\n", ret);
 		return -EIO;
 	}
+
+	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 %d\n", ret);
+		return -EIO;
+	}
+
 	return 0;
 }
-- 
2.43.0