x86/dma: Get rid of iommu_pass_through

This variable has no users anymore. Remove it and tell the
IOMMU code via its new functions about requested DMA modes.
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

arch/x86/include/asm/iommu.h

@@ -4,7 +4,6 @@
 
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
-extern int iommu_pass_through;
 
 /* 10 seconds */
 #define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)

arch/x86/kernel/pci-dma.c

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/dma-direct.h>
 #include <linux/dma-debug.h>
+#include <linux/iommu.h>
 #include <linux/dmar.h>
 #include <linux/export.h>
 #include <linux/memblock.h>
@@ -34,21 +35,6 @@ int no_iommu __read_mostly;
 /* Set this to 1 if there is a HW IOMMU in the system */
 int iommu_detected __read_mostly = 0;
 
-/*
- * This variable becomes 1 if iommu=pt is passed on the kernel command line.
- * If this variable is 1, IOMMU implementations do no DMA translation for
- * devices and allow every device to access to whole physical memory. This is
- * useful if a user wants to use an IOMMU only for KVM device assignment to
- * guests and not for driver dma translation.
- * It is also possible to disable by default in kernel config, and enable with
- * iommu=nopt at boot time.
- */
-#ifdef CONFIG_IOMMU_DEFAULT_PASSTHROUGH
-int iommu_pass_through __read_mostly = 1;
-#else
-int iommu_pass_through __read_mostly;
-#endif
-
 extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
 
 void __init pci_iommu_alloc(void)
@@ -120,9 +106,9 @@ static __init int iommu_setup(char *p)
 			swiotlb = 1;
 #endif
 		if (!strncmp(p, "pt", 2))
-			iommu_pass_through = 1;
+			iommu_set_default_passthrough(true);
 		if (!strncmp(p, "nopt", 4))
-			iommu_pass_through = 0;
+			iommu_set_default_translated(true);
 
 		gart_parse_options(p);