4 files changed, 26 insertions, 2 deletions

diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
index 807582335a98..6d228ccd884d 100644
--- a/drivers/misc/cxl/api.c
+++ b/drivers/misc/cxl/api.c
@@ -183,6 +183,7 @@ int cxl_start_context(struct cxl_context *ctx, u64 wed,
 		ctx->pid = get_task_pid(task, PIDTYPE_PID);
 		ctx->glpid = get_task_pid(task->group_leader, PIDTYPE_PID);
 		kernel = false;
+		ctx->real_mode = false;
 	}
 
 	cxl_ctx_get();
@@ -219,6 +220,24 @@ void cxl_set_master(struct cxl_context *ctx)
 }
 EXPORT_SYMBOL_GPL(cxl_set_master);
 
+int cxl_set_translation_mode(struct cxl_context *ctx, bool real_mode)
+{
+	if (ctx->status == STARTED) {
+		/*
+		 * We could potentially update the PE and issue an update LLCMD
+		 * to support this, but it doesn't seem to have a good use case
+		 * since it's trivial to just create a second kernel context
+		 * with different translation modes, so until someone convinces
+		 * me otherwise:
+		 */
+		return -EBUSY;
+	}
+
+	ctx->real_mode = real_mode;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_set_translation_mode);
+
 /* wrappers around afu_* file ops which are EXPORTED */
 int cxl_fd_open(struct inode *inode, struct file *file)
 {
diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
index 2823fb32fcf6..9dd3a0e7917f 100644
--- a/drivers/misc/cxl/cxl.h
+++ b/drivers/misc/cxl/cxl.h
@@ -514,6 +514,7 @@ struct cxl_context {
 	bool pe_inserted;
 	bool master;
 	bool kernel;
+	bool real_mode;
 	bool pending_irq;
 	bool pending_fault;
 	bool pending_afu_err;
diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c
index 769971c065b4..c2815b97de2e 100644
--- a/drivers/misc/cxl/guest.c
+++ b/drivers/misc/cxl/guest.c
@@ -617,6 +617,9 @@ static int guest_attach_process(struct cxl_context *ctx, bool kernel, u64 wed, u
 {
 	pr_devel("in %s\n", __func__);
 
+	if (ctx->real_mode)
+		return -EPERM;
+
 	ctx->kernel = kernel;
 	if (ctx->afu->current_mode == CXL_MODE_DIRECTED)
 		return attach_afu_directed(ctx, wed, amr);
diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
index 5d4fb9fd84bc..98f2cac45162 100644
--- a/drivers/misc/cxl/native.c
+++ b/drivers/misc/cxl/native.c
@@ -494,8 +494,9 @@ static u64 calculate_sr(struct cxl_context *ctx)
 	if (mfspr(SPRN_LPCR) & LPCR_TC)
 		sr |= CXL_PSL_SR_An_TC;
 	if (ctx->kernel) {
-		sr |= CXL_PSL_SR_An_R | (mfmsr() & MSR_SF);
-		sr |= CXL_PSL_SR_An_HV;
+		if (!ctx->real_mode)
+			sr |= CXL_PSL_SR_An_R;
+		sr |= (mfmsr() & MSR_SF) | CXL_PSL_SR_An_HV;
 	} else {
 		sr |= CXL_PSL_SR_An_PR | CXL_PSL_SR_An_R;
 		sr &= ~(CXL_PSL_SR_An_HV);