[PATCH v2 06/11] coco: guest: arm64: Add support for reading cached objects from host

["Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>]

Teach rsi_device_start() to pull the interface report and device
certificate from the host by querying size, sharing a decrypted buffer
for the read, copying the payload to private memory. Also track the
fetched blobs in struct cca_guest_dsc so later stages can hand them to
the attestation flow.

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 arch/arm64/include/asm/rhi.h             |  7 +++
 drivers/virt/coco/arm-cca-guest/rhi-da.c | 80 ++++++++++++++++++++++++
 drivers/virt/coco/arm-cca-guest/rhi-da.h |  1 +
 drivers/virt/coco/arm-cca-guest/rsi-da.h |  8 +++
 4 files changed, 96 insertions(+)

diff --git a/arch/arm64/include/asm/rhi.h b/arch/arm64/include/asm/rhi.h
index ce2ed8a440c3..738470dfb869 100644
--- a/arch/arm64/include/asm/rhi.h
+++ b/arch/arm64/include/asm/rhi.h
@@ -39,6 +39,13 @@
 				 RHI_DA_FEATURE_VDEV_SET_TDI_STATE)
 #define RHI_DA_FEATURES			SMC_RHI_CALL(0x004B)
 
+#define RHI_DA_OBJECT_CERTIFICATE		0x1
+#define RHI_DA_OBJECT_MEASUREMENT		0x2
+#define RHI_DA_OBJECT_INTERFACE_REPORT		0x3
+#define RHI_DA_OBJECT_VCA			0x4
+#define RHI_DA_OBJECT_SIZE		SMC_RHI_CALL(0x004C)
+#define RHI_DA_OBJECT_READ		SMC_RHI_CALL(0x004D)
+
 #define RHI_DA_VDEV_CONTINUE		SMC_RHI_CALL(0x0051)
 #define RHI_DA_VDEV_GET_INTERFACE_REPORT SMC_RHI_CALL(0x0052)
 
diff --git a/drivers/virt/coco/arm-cca-guest/rhi-da.c b/drivers/virt/coco/arm-cca-guest/rhi-da.c
index aa17bb3ee562..d29aee0fca58 100644
--- a/drivers/virt/coco/arm-cca-guest/rhi-da.c
+++ b/drivers/virt/coco/arm-cca-guest/rhi-da.c
@@ -248,3 +248,83 @@ int rhi_update_vdev_measurements_cache(struct pci_dev *pdev,
 
 	return ret;
 }
+
+int rhi_read_cached_object(int vdev_id, int da_object_type, void **object, int *object_size)
+{
+	int ret;
+	int max_data_len;
+	struct page *shared_pages;
+	void *data_buf_shared, *data_buf_private;
+	struct rsi_host_call *rhicall;
+
+	rhicall = kmalloc(sizeof(struct rsi_host_call), GFP_KERNEL);
+	if (!rhicall)
+		return -ENOMEM;
+
+	rhicall->imm = 0;
+	rhicall->gprs[0] = RHI_DA_OBJECT_SIZE;
+	rhicall->gprs[1] = vdev_id;
+	rhicall->gprs[2] = da_object_type;
+
+	ret = rsi_host_call(virt_to_phys(rhicall));
+	if (ret != RSI_SUCCESS) {
+		ret = -EIO;
+		goto err_return;
+	}
+
+	if (rhicall->gprs[0] != RHI_DA_SUCCESS) {
+		ret = -EIO;
+		goto err_return;
+	}
+
+	/* validate against the max cache object size used on host. */
+	max_data_len = rhicall->gprs[1];
+	if (max_data_len > MAX_CACHE_OBJ_SIZE || max_data_len == 0) {
+		ret = -EIO;
+		goto err_return;
+	}
+	*object_size = max_data_len;
+
+	data_buf_private = kmalloc(*object_size, GFP_KERNEL);
+	if (!data_buf_private) {
+		ret = -ENOMEM;
+		goto err_return;
+	}
+
+	shared_pages = alloc_shared_pages(NUMA_NO_NODE, GFP_KERNEL, max_data_len);
+	if (!shared_pages) {
+		ret = -ENOMEM;
+		goto err_shared_alloc;
+	}
+	data_buf_shared = page_address(shared_pages);
+
+	rhicall->imm = 0;
+	rhicall->gprs[0] = RHI_DA_OBJECT_READ;
+	rhicall->gprs[1] = vdev_id;
+	rhicall->gprs[2] = da_object_type;
+	rhicall->gprs[3] = 0; /* offset within the data buffer */
+	rhicall->gprs[4] = max_data_len;
+	rhicall->gprs[5] = virt_to_phys(data_buf_shared);
+	ret = rsi_host_call(virt_to_phys(rhicall));
+	if (ret != RSI_SUCCESS || rhicall->gprs[0] != RHI_DA_SUCCESS) {
+		ret = -EIO;
+		goto err_rhi_call;
+	}
+
+	memcpy(data_buf_private, data_buf_shared, *object_size);
+	free_shared_pages(shared_pages, max_data_len);
+
+	*object = data_buf_private;
+	kfree(rhicall);
+	return 0;
+
+err_rhi_call:
+	free_shared_pages(shared_pages, max_data_len);
+err_shared_alloc:
+	kfree(data_buf_private);
+err_return:
+	*object = NULL;
+	*object_size = 0;
+	kfree(rhicall);
+	return ret;
+}
diff --git a/drivers/virt/coco/arm-cca-guest/rhi-da.h b/drivers/virt/coco/arm-cca-guest/rhi-da.h
index f90e0e715073..303d19a80cd0 100644
--- a/drivers/virt/coco/arm-cca-guest/rhi-da.h
+++ b/drivers/virt/coco/arm-cca-guest/rhi-da.h
@@ -14,4 +14,5 @@ int rhi_vdev_set_tdi_state(struct pci_dev *pdev, unsigned long target_state);
 int rhi_update_vdev_interface_report_cache(struct pci_dev *pdev);
 int rhi_update_vdev_measurements_cache(struct pci_dev *pdev,
 				       struct rhi_vdev_measurement_params *params);
+int rhi_read_cached_object(int vdev_id, int da_object_type, void **object, int *object_size);
 #endif
diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.h b/drivers/virt/coco/arm-cca-guest/rsi-da.h
index 3b01182924bc..fa9cc01095da 100644
--- a/drivers/virt/coco/arm-cca-guest/rsi-da.h
+++ b/drivers/virt/coco/arm-cca-guest/rsi-da.h
@@ -10,8 +10,16 @@
 #include <linux/pci-tsm.h>
 #include <asm/rsi_smc.h>
 
+#define MAX_CACHE_OBJ_SIZE	SZ_16M
+
 struct cca_guest_dsc {
 	struct pci_tsm_devsec pci;
+	void *interface_report;
+	int interface_report_size;
+	void *certificate;
+	int certificate_size;
+	void *measurements;
+	int measurements_size;
 };
 
 static inline struct cca_guest_dsc *to_cca_guest_dsc(struct pci_dev *pdev)
-- 
2.43.0