[PATCH rdma-next 02/23] net/mlx5: Derive adversarial mode from CC guest memory encryption

[Yishai Hadas <yishaih@nvidia.com>]

Add mlx5_is_adversarial() to report whether the driver treats the NIC
as untrusted. In a confidential computing guest, the hypervisor and any
passthrough device are outside the guest's trust boundary, so the mode
is derived from cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT).

This turns adversarial mode on automatically in such guests, without
any administrator configuration.

Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/main.c | 7 +++++++
 include/linux/mlx5/driver.h                    | 1 +
 2 files changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/main.c b/drivers/net/ethernet/mellanox/mlx5/core/main.c
index 1a45474ce03d..f9e10464a71b 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/main.c
@@ -31,6 +31,7 @@
  */
 
 #include <linux/highmem.h>
+#include <linux/cc_platform.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/errno.h>
@@ -484,6 +485,12 @@ bool mlx5_is_roce_on(struct mlx5_core_dev *dev)
 }
 EXPORT_SYMBOL(mlx5_is_roce_on);
 
+bool mlx5_is_adversarial(void)
+{
+	return cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT);
+}
+EXPORT_SYMBOL_GPL(mlx5_is_adversarial);
+
 static int handle_hca_cap_2(struct mlx5_core_dev *dev, void *set_ctx)
 {
 	bool do_set = false;
diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
index a1275e6aa6c1..3d3bc16e581d 100644
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -1328,6 +1328,7 @@ enum {
 };
 
 bool mlx5_is_roce_on(struct mlx5_core_dev *dev);
+bool mlx5_is_adversarial(void);
 
 static inline bool mlx5_get_roce_state(struct mlx5_core_dev *dev)
 {
-- 
2.18.1