cxl: Isolate a few bare-metal-specific calls

A few functions are mostly common between bare-metal and guest and
just need minor tuning. To avoid crowding the backend API, introduce a
few 'if' based on the CPU being in HV mode.

Co-authored-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Reviewed-by: Manoj Kumar <manoj@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/drivers/misc/cxl/fault.c b/drivers/misc/cxl/fault.c
index ab740a1..9a8650b 100644
--- a/drivers/misc/cxl/fault.c
+++ b/drivers/misc/cxl/fault.c
@@ -254,14 +254,17 @@
 	u64 dar = ctx->dar;
 	struct mm_struct *mm = NULL;
 
-	if (cxl_p2n_read(ctx->afu, CXL_PSL_DSISR_An) != dsisr ||
-	    cxl_p2n_read(ctx->afu, CXL_PSL_DAR_An) != dar ||
-	    cxl_p2n_read(ctx->afu, CXL_PSL_PEHandle_An) != ctx->pe) {
-		/* Most likely explanation is harmless - a dedicated process
-		 * has detached and these were cleared by the PSL purge, but
-		 * warn about it just in case */
-		dev_notice(&ctx->afu->dev, "cxl_handle_fault: Translation fault regs changed\n");
-		return;
+	if (cpu_has_feature(CPU_FTR_HVMODE)) {
+		if (cxl_p2n_read(ctx->afu, CXL_PSL_DSISR_An) != dsisr ||
+		    cxl_p2n_read(ctx->afu, CXL_PSL_DAR_An) != dar ||
+		    cxl_p2n_read(ctx->afu, CXL_PSL_PEHandle_An) != ctx->pe) {
+			/* Most likely explanation is harmless - a dedicated
+			 * process has detached and these were cleared by the
+			 * PSL purge, but warn about it just in case
+			 */
+			dev_notice(&ctx->afu->dev, "cxl_handle_fault: Translation fault regs changed\n");
+			return;
+		}
 	}
 
 	/* Early return if the context is being / has been detached */