[PATCH 07/11] x86: remove the IOMMU table infrastructure

Christoph Hellwig
2022-02-22T15:35:10Z

The IOMMU table tries to separate the different IOMMUs into different
backends, but actually requires various cross calls.

Rewrite the code to do the generic swiotlb/swiotlb-xen setup directly
in pci-dma.c and then just call into the IOMMU drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/ia64/include/asm/iommu_table.h | 7 --
arch/x86/include/asm/dma-mapping.h | 1 -
arch/x86/include/asm/gart.h | 5 +-
arch/x86/include/asm/iommu.h | 6 ++
arch/x86/include/asm/iommu_table.h | 102 ----------------------
arch/x86/include/asm/swiotlb.h | 30 -------
arch/x86/include/asm/xen/swiotlb-xen.h | 2 -
arch/x86/kernel/Makefile | 2 -
arch/x86/kernel/amd_gart_64.c | 5 +-
arch/x86/kernel/aperture_64.c | 14 ++--
arch/x86/kernel/pci-dma.c | 112 ++++++++++++++++++++-----
arch/x86/kernel/pci-iommu_table.c | 77 -----------------
arch/x86/kernel/pci-swiotlb.c | 77 -----------------
arch/x86/kernel/tboot.c | 1 -
arch/x86/kernel/vmlinux.lds.S | 12 ---
arch/x86/xen/Makefile | 2 -
arch/x86/xen/pci-swiotlb-xen.c | 96 ---------------------
drivers/iommu/amd/init.c | 6 --
drivers/iommu/amd/iommu.c | 5 +-
drivers/iommu/intel/dmar.c | 6 +-
include/linux/dmar.h | 6 +-
21 files changed, 115 insertions(+), 459 deletions(-)
delete mode 100644 arch/ia64/include/asm/iommu_table.h
delete mode 100644 arch/x86/include/asm/iommu_table.h
delete mode 100644 arch/x86/include/asm/swiotlb.h
delete mode 100644 arch/x86/kernel/pci-iommu_table.c
delete mode 100644 arch/x86/kernel/pci-swiotlb.c
delete mode 100644 arch/x86/xen/pci-swiotlb-xen.c

diff --git a/arch/ia64/include/asm/iommu_table.h b/arch/ia64/include/asm/iommu_table.h
deleted file mode 100644
index cc96116ac276a..0000000000000
--- a/arch/ia64/include/asm/iommu_table.h
+++ /dev/null
@@ -1,7 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_IA64_IOMMU_TABLE_H
-#define _ASM_IA64_IOMMU_TABLE_H
-
-#define IOMMU_INIT_POST(_detect)
-
-#endif /* _ASM_IA64_IOMMU_TABLE_H */
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index bb1654fe0ce74..256fd8115223d 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -9,7 +9,6 @@

#include <linux/scatterlist.h>
#include <asm/io.h>
-#include <asm/swiotlb.h>

extern int iommu_merge;
extern int panic_on_overflow;
diff --git a/arch/x86/include/asm/gart.h b/arch/x86/include/asm/gart.h
index 3185565743459..5af8088a10df6 100644
--- a/arch/x86/include/asm/gart.h
+++ b/arch/x86/include/asm/gart.h
@@ -38,7 +38,7 @@ extern int gart_iommu_aperture_disabled;
extern void early_gart_iommu_check(void);
extern int gart_iommu_init(void);
extern void __init gart_parse_options(char *);
-extern int gart_iommu_hole_init(void);
+void gart_iommu_hole_init(void);

#else
#define gart_iommu_aperture 0
@@ -51,9 +51,8 @@ static inline void early_gart_iommu_check(void)
static inline void gart_parse_options(char *options)
{
}
-static inline int gart_iommu_hole_init(void)
+static inline void gart_iommu_hole_init(void)
{
- return -ENODEV;
}
#endif

diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index bf1ed2ddc74bd..dba89ed40d38d 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -9,6 +9,12 @@
extern int force_iommu, no_iommu;
extern int iommu_detected;

+#ifdef CONFIG_SWIOTLB
+extern bool x86_swiotlb_enable;
+#else
+#define x86_swiotlb_enable false
+#endif
+
/* 10 seconds */
#define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)

diff --git a/arch/x86/include/asm/iommu_table.h b/arch/x86/include/asm/iommu_table.h
deleted file mode 100644
index 1fb3fd1a83c25..0000000000000
--- a/arch/x86/include/asm/iommu_table.h
+++ /dev/null
@@ -1,102 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_X86_IOMMU_TABLE_H
-#define _ASM_X86_IOMMU_TABLE_H
-
-#include <asm/swiotlb.h>
-
-/*
- * History lesson:
- * The execution chain of IOMMUs in 2.6.36 looks as so:
- *
- * [xen-swiotlb]
- * |
- * +----[swiotlb *]--+
- * / | \
- * / | \
- * [GART] [Calgary] [Intel VT-d]
- * /
- * /
- * [AMD-Vi]
- *
- * *: if SWIOTLB detected 'iommu=soft'/'swiotlb=force' it would skip
- * over the rest of IOMMUs and unconditionally initialize the SWIOTLB.
- * Also it would surreptitiously initialize set the swiotlb=1 if there were
- * more than 4GB and if the user did not pass in 'iommu=off'. The swiotlb
- * flag would be turned off by all IOMMUs except the Calgary one.
- *
- * The IOMMU_INIT* macros allow a similar tree (or more complex if desired)
- * to be built by defining who we depend on.
- *
- * And all that needs to be done is to use one of the macros in the IOMMU
- * and the pci-dma.c will take care of the rest.
- */
-
-struct iommu_table_entry {
- initcall_t detect;
- initcall_t depend;
- void (*early_init)(void); /* No memory allocate available. */
- void (*late_init)(void); /* Yes, can allocate memory. */
-#define IOMMU_FINISH_IF_DETECTED (1<<0)
-#define IOMMU_DETECTED (1<<1)
- int flags;
-};
-/*
- * Macro fills out an entry in the .iommu_table that is equivalent
- * to the fields that 'struct iommu_table_entry' has. The entries
- * that are put in the .iommu_table section are not put in any order
- * hence during boot-time we will have to resort them based on
- * dependency. */
-
-
-#define __IOMMU_INIT(_detect, _depend, _early_init, _late_init, _finish)\
- static const struct iommu_table_entry \
- __iommu_entry_##_detect __used \
- __attribute__ ((unused, __section__(".iommu_table"), \
- aligned((sizeof(void *))))) \
- = {_detect, _depend, _early_init, _late_init, \
- _finish ? IOMMU_FINISH_IF_DETECTED : 0}
-/*
- * The simplest IOMMU definition. Provide the detection routine
- * and it will be run after the SWIOTLB and the other IOMMUs
- * that utilize this macro. If the IOMMU is detected (ie, the
- * detect routine returns a positive value), the other IOMMUs
- * are also checked. You can use IOMMU_INIT_POST_FINISH if you prefer
- * to stop detecting the other IOMMUs after yours has been detected.
- */
-#define IOMMU_INIT_POST(_detect) \
- __IOMMU_INIT(_detect, pci_swiotlb_detect_4gb, NULL, NULL, 0)
-
-#define IOMMU_INIT_POST_FINISH(detect) \
- __IOMMU_INIT(_detect, pci_swiotlb_detect_4gb, NULL, NULL, 1)
-
-/*
- * A more sophisticated version of IOMMU_INIT. This variant requires:
- * a). A detection routine function.
- * b). The name of the detection routine we depend on to get called
- * before us.
- * c). The init routine which gets called if the detection routine
- * returns a positive value from the pci_iommu_alloc. This means
- * no presence of a memory allocator.
- * d). Similar to the 'init', except that this gets called from pci_iommu_init
- * where we do have a memory allocator.
- *
- * The standard IOMMU_INIT differs from the IOMMU_INIT_FINISH variant
- * in that the former will continue detecting other IOMMUs in the call
- * list after the detection routine returns a positive number, while the
- * latter will stop the execution chain upon first successful detection.
- * Both variants will still call the 'init' and 'late_init' functions if
- * they are set.
- */
-#define IOMMU_INIT_FINISH(_detect, _depend, _init, _late_init) \
- __IOMMU_INIT(_detect, _depend, _init, _late_init, 1)
-
-#define IOMMU_INIT(_detect, _depend, _init, _late_init) \
- __IOMMU_INIT(_detect, _depend, _init, _late_init, 0)
-
-void sort_iommu_table(struct iommu_table_entry *start,
- struct iommu_table_entry *finish);
-
-void check_iommu_entries(struct iommu_table_entry *start,
- struct iommu_table_entry *finish);
-
-#endif /* _ASM_X86_IOMMU_TABLE_H */
diff --git a/arch/x86/include/asm/swiotlb.h b/arch/x86/include/asm/swiotlb.h
deleted file mode 100644
index ff6c92eff035a..0000000000000
--- a/arch/x86/include/asm/swiotlb.h
+++ /dev/null
@@ -1,30 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_X86_SWIOTLB_H
-#define _ASM_X86_SWIOTLB_H
-
-#include <linux/swiotlb.h>
-
-#ifdef CONFIG_SWIOTLB
-extern int swiotlb;
-extern int __init pci_swiotlb_detect_override(void);
-extern int __init pci_swiotlb_detect_4gb(void);
-extern void __init pci_swiotlb_init(void);
-extern void __init pci_swiotlb_late_init(void);
-#else
-#define swiotlb 0
-static inline int pci_swiotlb_detect_override(void)
-{
- return 0;
-}
-static inline int pci_swiotlb_detect_4gb(void)
-{
- return 0;
-}
-static inline void pci_swiotlb_init(void)
-{
-}
-static inline void pci_swiotlb_late_init(void)
-{
-}
-#endif
-#endif /* _ASM_X86_SWIOTLB_H */
diff --git a/arch/x86/include/asm/xen/swiotlb-xen.h b/arch/x86/include/asm/xen/swiotlb-xen.h
index 66b4ddde77430..e5a90b42e4dde 100644
--- a/arch/x86/include/asm/xen/swiotlb-xen.h
+++ b/arch/x86/include/asm/xen/swiotlb-xen.h
@@ -3,10 +3,8 @@
#define _ASM_X86_SWIOTLB_XEN_H

#ifdef CONFIG_SWIOTLB_XEN
-extern int __init pci_xen_swiotlb_detect(void);
extern int pci_xen_swiotlb_init_late(void);
#else
-#define pci_xen_swiotlb_detect NULL
static inline int pci_xen_swiotlb_init_late(void) { return -ENXIO; }
#endif

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 6aef9ee28a394..2851d4f0aa0d2 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -71,7 +71,6 @@ obj-y += bootflag.o e820.o
obj-y += pci-dma.o quirks.o topology.o kdebugfs.o
obj-y += alternative.o i8253.o hw_breakpoint.o
obj-y += tsc.o tsc_msr.o io_delay.o rtc.o
-obj-y += pci-iommu_table.o
obj-y += resource.o
obj-y += irqflags.o
obj-y += static_call.o
@@ -136,7 +135,6 @@ obj-$(CONFIG_PCSPKR_PLATFORM) += pcspeaker.o

obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o

-obj-$(CONFIG_SWIOTLB) += pci-swiotlb.o
obj-$(CONFIG_OF) += devicetree.o
obj-$(CONFIG_UPROBES) += uprobes.o

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index ed837383de5c8..194d54eed5376 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -38,11 +38,9 @@
#include <asm/iommu.h>
#include <asm/gart.h>
#include <asm/set_memory.h>
-#include <asm/swiotlb.h>
#include <asm/dma.h>
#include <asm/amd_nb.h>
#include <asm/x86_init.h>
-#include <asm/iommu_table.h>

static unsigned long iommu_bus_base; /* GART remapping area (physical) */
static unsigned long iommu_size; /* size of remapping area bytes */
@@ -808,7 +806,7 @@ int __init gart_iommu_init(void)
flush_gart();
dma_ops = &gart_dma_ops;
x86_platform.iommu_shutdown = gart_iommu_shutdown;
- swiotlb = 0;
+ x86_swiotlb_enable = false;

return 0;
}
@@ -842,4 +840,3 @@ void __init gart_parse_options(char *p)
}
}
}
-IOMMU_INIT_POST(gart_iommu_hole_init);
diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index af3ba08b684b5..7a5630d904b23 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -392,7 +392,7 @@ void __init early_gart_iommu_check(void)

static int __initdata printed_gart_size_msg;

-int __init gart_iommu_hole_init(void)
+void __init gart_iommu_hole_init(void)
{
u32 agp_aper_base = 0, agp_aper_order = 0;
u32 aper_size, aper_alloc = 0, aper_order = 0, last_aper_order = 0;
@@ -401,11 +401,11 @@ int __init gart_iommu_hole_init(void)
int i, node;

if (!amd_gart_present())
- return -ENODEV;
+ return;

if (gart_iommu_aperture_disabled || !fix_aperture ||
!early_pci_allowed())
- return -ENODEV;
+ return;

pr_info("Checking aperture...\n");

@@ -491,10 +491,8 @@ int __init gart_iommu_hole_init(void)
* and fixed up the northbridge
*/
exclude_from_core(last_aper_base, last_aper_order);
-
- return 1;
}
- return 0;
+ return;
}

if (!fallback_aper_force) {
@@ -527,7 +525,7 @@ int __init gart_iommu_hole_init(void)
panic("Not enough memory for aperture");
}
} else {
- return 0;
+ return;
}

/*
@@ -561,6 +559,4 @@ int __init gart_iommu_hole_init(void)
}

set_up_gart_resume(aper_order, aper_alloc);
-
- return 1;
}
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index de234e7a8962e..32c9cd9d7c257 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -7,13 +7,16 @@
#include <linux/memblock.h>
#include <linux/gfp.h>
#include <linux/pci.h>
+#include <linux/amd-iommu.h>

#include <asm/proto.h>
#include <asm/dma.h>
#include <asm/iommu.h>
#include <asm/gart.h>
#include <asm/x86_init.h>
-#include <asm/iommu_table.h>
+
+#include <xen/xen.h>
+#include <xen/swiotlb-xen.h>

static bool disable_dac_quirk __read_mostly;

@@ -34,24 +37,63 @@ int no_iommu __read_mostly;
/* Set this to 1 if there is a HW IOMMU in the system */
int iommu_detected __read_mostly = 0;

-extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
+#ifdef CONFIG_SWIOTLB
+bool x86_swiotlb_enable;
+static bool xen_swiotlb;

-void __init pci_iommu_alloc(void)
+/*
+ * If 4GB or more detected (and iommu=off not set) or if SME is active
+ * then set swiotlb to 1 and return 1.
+ */
+static void __init pci_swiotlb_detect_4gb(void)
{
- struct iommu_table_entry *p;
-
- sort_iommu_table(__iommu_table, __iommu_table_end);
- check_iommu_entries(__iommu_table, __iommu_table_end);
-
- for (p = __iommu_table; p < __iommu_table_end; p++) {
- if (p && p->detect && p->detect() > 0) {
- p->flags |= IOMMU_DETECTED;
- if (p->early_init)
- p->early_init();
- if (p->flags & IOMMU_FINISH_IF_DETECTED)
- break;
+#ifdef CONFIG_SWIOTLB_XEN
+ if (xen_pv_domain()) {
+ if (xen_initial_domain() || x86_swiotlb_enable ||
+ swiotlb_force = SWIOTLB_FORCE) {
+ xen_swiotlb = true;
+ xen_swiotlb_init_early();
+ dma_ops = &xen_swiotlb_dma_ops;
+
+#ifdef CONFIG_PCI
+ /* Make sure ACS will be enabled */
+ pci_request_acs();
+#endif
}
+ x86_swiotlb_enable = false;
+ return;
}
+#endif /* CONFIG_SWIOTLB_XEN */
+
+ /* don't initialize swiotlb if iommu=off (no_iommu=1) */
+ if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
+ x86_swiotlb_enable = true;
+
+ /*
+ * Set swiotlb to 1 so that bounce buffers are allocated and used for
+ * devices that can't support DMA to encrypted memory.
+ */
+ if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
+ x86_swiotlb_enable = true;
+
+ if (swiotlb_force = SWIOTLB_FORCE)
+ x86_swiotlb_enable = true;
+}
+#else
+static inline void __init pci_swiotlb_detect_4gb(void)
+{
+}
+#endif /* CONFIG_SWIOTLB */
+
+void __init pci_iommu_alloc(void)
+{
+ pci_swiotlb_detect_4gb();
+ gart_iommu_hole_init();
+ amd_iommu_detect();
+ detect_intel_iommu();
+
+ if (x86_swiotlb_enable)
+ swiotlb_init(0);
}

/*
@@ -102,7 +144,7 @@ static __init int iommu_setup(char *p)
}
#ifdef CONFIG_SWIOTLB
if (!strncmp(p, "soft", 4))
- swiotlb = 1;
+ x86_swiotlb_enable = 1;
#endif
if (!strncmp(p, "pt", 2))
iommu_set_default_passthrough(true);
@@ -121,14 +163,18 @@ early_param("iommu", iommu_setup);

static int __init pci_iommu_init(void)
{
- struct iommu_table_entry *p;
-
x86_init.iommu.iommu_init();

- for (p = __iommu_table; p < __iommu_table_end; p++) {
- if (p && (p->flags & IOMMU_DETECTED) && p->late_init)
- p->late_init();
+#ifdef CONFIG_SWIOTLB
+ /* An IOMMU turned us off. */
+ if (x86_swiotlb_enable) {
+ printk(KERN_INFO "PCI-DMA: "
+ "Using software bounce buffering for IO (SWIOTLB)\n");
+ swiotlb_print_info();
+ } else {
+ swiotlb_exit();
}
+#endif

return 0;
}
@@ -154,3 +200,27 @@ static void via_no_dac(struct pci_dev *dev)
DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);
#endif
+
+#ifdef CONFIG_SWIOTLB_XEN
+int pci_xen_swiotlb_init_late(void)
+{
+ int rc;
+
+ if (xen_swiotlb)
+ return 0;
+
+ rc = xen_swiotlb_init();
+ if (rc)
+ return rc;
+
+ /* XXX: this switches the dma ops under live devices! */
+ dma_ops = &xen_swiotlb_dma_ops;
+#ifdef CONFIG_PCI
+ /* Make sure ACS will be enabled */
+ pci_request_acs();
+#endif
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
+#endif /* CONFIG_SWIOTLB_XEN */
diff --git a/arch/x86/kernel/pci-iommu_table.c b/arch/x86/kernel/pci-iommu_table.c
deleted file mode 100644
index 42e92ec62973b..0000000000000
--- a/arch/x86/kernel/pci-iommu_table.c
+++ /dev/null
@@ -1,77 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/dma-mapping.h>
-#include <asm/iommu_table.h>
-#include <linux/string.h>
-#include <linux/kallsyms.h>
-
-static struct iommu_table_entry * __init
-find_dependents_of(struct iommu_table_entry *start,
- struct iommu_table_entry *finish,
- struct iommu_table_entry *q)
-{
- struct iommu_table_entry *p;
-
- if (!q)
- return NULL;
-
- for (p = start; p < finish; p++)
- if (p->detect = q->depend)
- return p;
-
- return NULL;
-}
-
-
-void __init sort_iommu_table(struct iommu_table_entry *start,
- struct iommu_table_entry *finish) {
-
- struct iommu_table_entry *p, *q, tmp;
-
- for (p = start; p < finish; p++) {
-again:
- q = find_dependents_of(start, finish, p);
- /* We are bit sneaky here. We use the memory address to figure
- * out if the node we depend on is past our point, if so, swap.
- */
- if (q > p) {
- tmp = *p;
- memmove(p, q, sizeof(*p));
- *q = tmp;
- goto again;
- }
- }
-
-}
-
-#ifdef DEBUG
-void __init check_iommu_entries(struct iommu_table_entry *start,
- struct iommu_table_entry *finish)
-{
- struct iommu_table_entry *p, *q, *x;
-
- /* Simple cyclic dependency checker. */
- for (p = start; p < finish; p++) {
- q = find_dependents_of(start, finish, p);
- x = find_dependents_of(start, finish, q);
- if (p = x) {
- printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %pS depends on %pS and vice-versa. BREAKING IT.\n",
- p->detect, q->detect);
- /* Heavy handed way..*/
- x->depend = NULL;
- }
- }
-
- for (p = start; p < finish; p++) {
- q = find_dependents_of(p, finish, p);
- if (q && q > p) {
- printk(KERN_ERR "EXECUTION ORDER INVALID! %pS should be called before %pS!\n",
- p->detect, q->detect);
- }
- }
-}
-#else
-void __init check_iommu_entries(struct iommu_table_entry *start,
- struct iommu_table_entry *finish)
-{
-}
-#endif
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
deleted file mode 100644
index 814ab46a0dada..0000000000000
--- a/arch/x86/kernel/pci-swiotlb.c
+++ /dev/null
@@ -1,77 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include <linux/pci.h>
-#include <linux/cache.h>
-#include <linux/init.h>
-#include <linux/swiotlb.h>
-#include <linux/memblock.h>
-#include <linux/dma-direct.h>
-#include <linux/cc_platform.h>
-
-#include <asm/iommu.h>
-#include <asm/swiotlb.h>
-#include <asm/dma.h>
-#include <asm/xen/swiotlb-xen.h>
-#include <asm/iommu_table.h>
-
-int swiotlb __read_mostly;
-
-/*
- * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
- *
- * This returns non-zero if we are forced to use swiotlb (by the boot
- * option).
- */
-int __init pci_swiotlb_detect_override(void)
-{
- if (swiotlb_force = SWIOTLB_FORCE)
- swiotlb = 1;
-
- return swiotlb;
-}
-IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
- pci_xen_swiotlb_detect,
- pci_swiotlb_init,
- pci_swiotlb_late_init);
-
-/*
- * If 4GB or more detected (and iommu=off not set) or if SME is active
- * then set swiotlb to 1 and return 1.
- */
-int __init pci_swiotlb_detect_4gb(void)
-{
- /* don't initialize swiotlb if iommu=off (no_iommu=1) */
- if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
- swiotlb = 1;
-
- /*
- * Set swiotlb to 1 so that bounce buffers are allocated and used for
- * devices that can't support DMA to encrypted memory.
- */
- if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
- swiotlb = 1;
-
- return swiotlb;
-}
-IOMMU_INIT(pci_swiotlb_detect_4gb,
- pci_swiotlb_detect_override,
- pci_swiotlb_init,
- pci_swiotlb_late_init);
-
-void __init pci_swiotlb_init(void)
-{
- if (swiotlb)
- swiotlb_init(0);
-}
-
-void __init pci_swiotlb_late_init(void)
-{
- /* An IOMMU turned us off. */
- if (!swiotlb)
- swiotlb_exit();
- else {
- printk(KERN_INFO "PCI-DMA: "
- "Using software bounce buffering for IO (SWIOTLB)\n");
- swiotlb_print_info();
- }
-}
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index f9af561c3cd4f..0c1154a1c4032 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -24,7 +24,6 @@
#include <asm/processor.h>
#include <asm/bootparam.h>
#include <asm/pgalloc.h>
-#include <asm/swiotlb.h>
#include <asm/fixmap.h>
#include <asm/proto.h>
#include <asm/setup.h>
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 27f830345b6f0..bbe910c15b293 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -306,18 +306,6 @@ SECTIONS
*(.altinstr_replacement)
}

- /*
- * struct iommu_table_entry entries are injected in this section.
- * It is an array of IOMMUs which during run time gets sorted depending
- * on its dependency order. After rootfs_initcall is complete
- * this section can be safely removed.
- */
- .iommu_table : AT(ADDR(.iommu_table) - LOAD_OFFSET) {
- __iommu_table = .;
- *(.iommu_table)
- __iommu_table_end = .;
- }
-
. = ALIGN(8);
.apicdrivers : AT(ADDR(.apicdrivers) - LOAD_OFFSET) {
__apicdrivers = .;
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index 4953260e281c3..3c5b52fbe4a7f 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -47,6 +47,4 @@ obj-$(CONFIG_XEN_DEBUG_FS) += debugfs.o

obj-$(CONFIG_XEN_PV_DOM0) += vga.o

-obj-$(CONFIG_SWIOTLB_XEN) += pci-swiotlb-xen.o
-
obj-$(CONFIG_XEN_EFI) += efi.o
diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
deleted file mode 100644
index 46df59aeaa06a..0000000000000
--- a/arch/x86/xen/pci-swiotlb-xen.c
+++ /dev/null
@@ -1,96 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-/* Glue code to lib/swiotlb-xen.c */
-
-#include <linux/dma-map-ops.h>
-#include <linux/pci.h>
-#include <xen/swiotlb-xen.h>
-
-#include <asm/xen/hypervisor.h>
-#include <xen/xen.h>
-#include <asm/iommu_table.h>
-
-
-#include <asm/xen/swiotlb-xen.h>
-#ifdef CONFIG_X86_64
-#include <asm/iommu.h>
-#include <asm/dma.h>
-#endif
-#include <linux/export.h>
-
-static int xen_swiotlb __read_mostly;
-
-/*
- * pci_xen_swiotlb_detect - set xen_swiotlb to 1 if necessary
- *
- * This returns non-zero if we are forced to use xen_swiotlb (by the boot
- * option).
- */
-int __init pci_xen_swiotlb_detect(void)
-{
-
- if (!xen_pv_domain())
- return 0;
-
- /* If running as PV guest, either iommu=soft, or swiotlb=force will
- * activate this IOMMU. If running as PV privileged, activate it
- * irregardless.
- */
- if (xen_initial_domain() || swiotlb || swiotlb_force = SWIOTLB_FORCE)
- xen_swiotlb = 1;
-
- /* If we are running under Xen, we MUST disable the native SWIOTLB.
- * Don't worry about swiotlb_force flag activating the native, as
- * the 'swiotlb' flag is the only one turning it on. */
- swiotlb = 0;
-
-#ifdef CONFIG_X86_64
- /* pci_swiotlb_detect_4gb turns on native SWIOTLB if no_iommu = 0
- * (so no iommu=X command line over-writes).
- * Considering that PV guests do not want the *native SWIOTLB* but
- * only Xen SWIOTLB it is not useful to us so set no_iommu=1 here.
- */
- if (max_pfn > MAX_DMA32_PFN)
- no_iommu = 1;
-#endif
- return xen_swiotlb;
-}
-
-static void __init pci_xen_swiotlb_init(void)
-{
- if (xen_swiotlb) {
- xen_swiotlb_init_early();
- dma_ops = &xen_swiotlb_dma_ops;
-
-#ifdef CONFIG_PCI
- /* Make sure ACS will be enabled */
- pci_request_acs();
-#endif
- }
-}
-
-int pci_xen_swiotlb_init_late(void)
-{
- int rc;
-
- if (xen_swiotlb)
- return 0;
-
- rc = xen_swiotlb_init();
- if (rc)
- return rc;
-
- dma_ops = &xen_swiotlb_dma_ops;
-#ifdef CONFIG_PCI
- /* Make sure ACS will be enabled */
- pci_request_acs();
-#endif
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
-
-IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
- NULL,
- pci_xen_swiotlb_init,
- NULL);
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index b10fb52ea4428..721300cf90207 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -27,7 +27,6 @@
#include <asm/apic.h>
#include <asm/gart.h>
#include <asm/x86_init.h>
-#include <asm/iommu_table.h>
#include <asm/io_apic.h>
#include <asm/irq_remapping.h>
#include <asm/set_memory.h>
@@ -3237,11 +3236,6 @@ __setup("ivrs_ioapic", parse_ivrs_ioapic);
__setup("ivrs_hpet", parse_ivrs_hpet);
__setup("ivrs_acpihid", parse_ivrs_acpihid);

-IOMMU_INIT_FINISH(amd_iommu_detect,
- gart_iommu_hole_init,
- NULL,
- NULL);
-
bool amd_iommu_v2_supported(void)
{
return amd_iommu_v2_present;
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 461f1844ed1fb..4f9672b18ad1a 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -1834,7 +1834,10 @@ void amd_iommu_domain_update(struct protection_domain *domain)

static void __init amd_iommu_init_dma_ops(void)
{
- swiotlb = (iommu_default_passthrough() || sme_me_mask) ? 1 : 0;
+ if (iommu_default_passthrough() || sme_me_mask)
+ x86_swiotlb_enable = true;
+ else
+ x86_swiotlb_enable = false;
}

int __init amd_iommu_init_api(void)
diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 915bff76fe965..29bee4b210c5b 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -30,7 +30,6 @@
#include <linux/numa.h>
#include <linux/limits.h>
#include <asm/irq_remapping.h>
-#include <asm/iommu_table.h>
#include <trace/events/intel_iommu.h>

#include "../irq_remapping.h"
@@ -913,7 +912,7 @@ dmar_validate_one_drhd(struct acpi_dmar_header *entry, void *arg)
return 0;
}

-int __init detect_intel_iommu(void)
+void __init detect_intel_iommu(void)
{
int ret;
struct dmar_res_callback validate_drhd_cb = {
@@ -946,8 +945,6 @@ int __init detect_intel_iommu(void)
dmar_tbl = NULL;
}
up_write(&dmar_global_lock);
-
- return ret ? ret : 1;
}

static void unmap_iommu(struct intel_iommu *iommu)
@@ -2165,7 +2162,6 @@ static int __init dmar_free_unused_resources(void)
}

late_initcall(dmar_free_unused_resources);
-IOMMU_INIT_POST(detect_intel_iommu);

/*
* DMAR Hotplug Support
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 45e903d847335..cbd714a198a0a 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -121,7 +121,7 @@ extern int dmar_remove_dev_scope(struct dmar_pci_notify_info *info,
u16 segment, struct dmar_dev_scope *devices,
int count);
/* Intel IOMMU detection */
-extern int detect_intel_iommu(void);
+void detect_intel_iommu(void);
extern int enable_drhd_fault_handling(void);
extern int dmar_device_add(acpi_handle handle);
extern int dmar_device_remove(acpi_handle handle);
@@ -197,6 +197,10 @@ static inline bool dmar_platform_optin(void)
return false;
}

+static inline void detect_intel_iommu(void)
+{
+}
+
#endif /* CONFIG_DMAR_TABLE */

struct irte {
--
2.30.2