use generic dma-direct and swiotlb code for x86

use generic dma-direct and swiotlb code for x86

[Christoph Hellwig]

Hi all,

this series switches the x86 code the the dma-direct implementation
for direct (non-iommu) dma and the generic swiotlb ops.  This includes
getting rid of the special ops for the AMD memory encryption case and
the STA2x11 SOC.  The generic implementations are based on the x86
code, so they provide the same functionality.

[PATCH 01/13] x86: remove X86_PPRO_FENCE

[Christoph Hellwig]

There were only a few Pentium Pro multiprocessors systems where this
errata applied. They are more than 20 years old now, and we've slowly
dropped places where put the workarounds in and discouraged anyone
from enabling the workaround.

Get rid of it for good.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/Kconfig.cpu                        | 13 -------------
 arch/x86/entry/vdso/vdso32/vclock_gettime.c |  2 --
 arch/x86/include/asm/barrier.h              | 30 -----------------------------
 arch/x86/include/asm/io.h                   | 15 ---------------
 arch/x86/kernel/pci-nommu.c                 | 19 ------------------
 arch/x86/um/asm/barrier.h                   |  4 ----
 6 files changed, 83 deletions(-)

diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 8b8d2297d486..638411f22267 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -315,19 +315,6 @@ config X86_L1_CACHE_SHIFT
 	default "4" if MELAN || M486 || MGEODEGX1
 	default "5" if MWINCHIP3D || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE_LX
 
-config X86_PPRO_FENCE
-	bool "PentiumPro memory ordering errata workaround"
-	depends on M686 || M586MMX || M586TSC || M586 || M486 || MGEODEGX1
-	---help---
-	  Old PentiumPro multiprocessor systems had errata that could cause
-	  memory operations to violate the x86 ordering standard in rare cases.
-	  Enabling this option will attempt to work around some (but not all)
-	  occurrences of this problem, at the cost of much heavier spinlock and
-	  memory barrier operations.
-
-	  If unsure, say n here. Even distro kernels should think twice before
-	  enabling this: there are few systems, and an unlikely bug.
-
 config X86_F00F_BUG
 	def_bool y
 	depends on M586MMX || M586TSC || M586 || M486
diff --git a/arch/x86/entry/vdso/vdso32/vclock_gettime.c b/arch/x86/entry/vdso/vdso32/vclock_gettime.c
index 7780bbfb06ef..9242b28418d5 100644
--- a/arch/x86/entry/vdso/vdso32/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vdso32/vclock_gettime.c
@@ -5,8 +5,6 @@
 #undef CONFIG_OPTIMIZE_INLINING
 #endif
 
-#undef CONFIG_X86_PPRO_FENCE
-
 #ifdef CONFIG_X86_64
 
 /*
diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index e1259f043ae9..042b5e892ed1 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -52,11 +52,7 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
 #define barrier_nospec() alternative_2("", "mfence", X86_FEATURE_MFENCE_RDTSC, \
 					   "lfence", X86_FEATURE_LFENCE_RDTSC)
 
-#ifdef CONFIG_X86_PPRO_FENCE
-#define dma_rmb()	rmb()
-#else
 #define dma_rmb()	barrier()
-#endif
 #define dma_wmb()	barrier()
 
 #ifdef CONFIG_X86_32
@@ -68,30 +64,6 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
 #define __smp_wmb()	barrier()
 #define __smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0)
 
-#if defined(CONFIG_X86_PPRO_FENCE)
-
-/*
- * For this option x86 doesn't have a strong TSO memory
- * model and we should fall back to full barriers.
- */
-
-#define __smp_store_release(p, v)					\
-do {									\
-	compiletime_assert_atomic_type(*p);				\
-	__smp_mb();							\
-	WRITE_ONCE(*p, v);						\
-} while (0)
-
-#define __smp_load_acquire(p)						\
-({									\
-	typeof(*p) ___p1 = READ_ONCE(*p);				\
-	compiletime_assert_atomic_type(*p);				\
-	__smp_mb();							\
-	___p1;								\
-})
-
-#else /* regular x86 TSO memory ordering */
-
 #define __smp_store_release(p, v)					\
 do {									\
 	compiletime_assert_atomic_type(*p);				\
@@ -107,8 +79,6 @@ do {									\
 	___p1;								\
 })
 
-#endif
-
 /* Atomic operations are already serializing on x86 */
 #define __smp_mb__before_atomic()	barrier()
 #define __smp_mb__after_atomic()	barrier()
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 95e948627fd0..f6e5b9375d8c 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -232,21 +232,6 @@ extern void set_iounmap_nonlazy(void);
  */
 #define __ISA_IO_base ((char __iomem *)(PAGE_OFFSET))
 
-/*
- *	Cache management
- *
- *	This needed for two cases
- *	1. Out of order aware processors
- *	2. Accidentally out of order processors (PPro errata #51)
- */
-
-static inline void flush_write_buffers(void)
-{
-#if defined(CONFIG_X86_PPRO_FENCE)
-	asm volatile("lock; addl $0,0(%%esp)": : :"memory");
-#endif
-}
-
 #endif /* __KERNEL__ */
 
 extern void native_io_delay(void);
diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
index 618285e475c6..ac7ea3a8242f 100644
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -37,7 +37,6 @@ static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
 	WARN_ON(size == 0);
 	if (!check_addr("map_single", dev, bus, size))
 		return NOMMU_MAPPING_ERROR;
-	flush_write_buffers();
 	return bus;
 }
 
@@ -72,25 +71,9 @@ static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
 			return 0;
 		s->dma_length = s->length;
 	}
-	flush_write_buffers();
 	return nents;
 }
 
-static void nommu_sync_single_for_device(struct device *dev,
-			dma_addr_t addr, size_t size,
-			enum dma_data_direction dir)
-{
-	flush_write_buffers();
-}
-
-
-static void nommu_sync_sg_for_device(struct device *dev,
-			struct scatterlist *sg, int nelems,
-			enum dma_data_direction dir)
-{
-	flush_write_buffers();
-}
-
 static int nommu_mapping_error(struct device *dev, dma_addr_t dma_addr)
 {
 	return dma_addr == NOMMU_MAPPING_ERROR;
@@ -101,8 +84,6 @@ const struct dma_map_ops nommu_dma_ops = {
 	.free			= dma_generic_free_coherent,
 	.map_sg			= nommu_map_sg,
 	.map_page		= nommu_map_page,
-	.sync_single_for_device = nommu_sync_single_for_device,
-	.sync_sg_for_device	= nommu_sync_sg_for_device,
 	.is_phys		= 1,
 	.mapping_error		= nommu_mapping_error,
 	.dma_supported		= x86_dma_supported,
diff --git a/arch/x86/um/asm/barrier.h b/arch/x86/um/asm/barrier.h
index b7d73400ea29..f31e5d903161 100644
--- a/arch/x86/um/asm/barrier.h
+++ b/arch/x86/um/asm/barrier.h
@@ -30,11 +30,7 @@
 
 #endif /* CONFIG_X86_32 */
 
-#ifdef CONFIG_X86_PPRO_FENCE
-#define dma_rmb()	rmb()
-#else /* CONFIG_X86_PPRO_FENCE */
 #define dma_rmb()	barrier()
-#endif /* CONFIG_X86_PPRO_FENCE */
 #define dma_wmb()	barrier()
 
 #include <asm-generic/barrier.h>
-- 
2.14.2

[PATCH 02/13] x86: remove dma_alloc_coherent_mask

[Christoph Hellwig]

These days all devices (including the ISA fallback device) have a coherent
DMA mask set, so remove the workaround.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/include/asm/dma-mapping.h | 18 ++----------------
 arch/x86/kernel/pci-dma.c          | 10 ++++------
 arch/x86/mm/mem_encrypt.c          |  4 +---
 drivers/xen/swiotlb-xen.c          | 16 +---------------
 4 files changed, 8 insertions(+), 40 deletions(-)

diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 6277c83c0eb1..545bf3721bc0 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -44,26 +44,12 @@ extern void dma_generic_free_coherent(struct device *dev, size_t size,
 				      void *vaddr, dma_addr_t dma_addr,
 				      unsigned long attrs);
 
-static inline unsigned long dma_alloc_coherent_mask(struct device *dev,
-						    gfp_t gfp)
-{
-	unsigned long dma_mask = 0;
-
-	dma_mask = dev->coherent_dma_mask;
-	if (!dma_mask)
-		dma_mask = (gfp & GFP_DMA) ? DMA_BIT_MASK(24) : DMA_BIT_MASK(32);
-
-	return dma_mask;
-}
-
 static inline gfp_t dma_alloc_coherent_gfp_flags(struct device *dev, gfp_t gfp)
 {
-	unsigned long dma_mask = dma_alloc_coherent_mask(dev, gfp);
-
-	if (dma_mask <= DMA_BIT_MASK(24))
+	if (dev->coherent_dma_mask <= DMA_BIT_MASK(24))
 		gfp |= GFP_DMA;
 #ifdef CONFIG_X86_64
-	if (dma_mask <= DMA_BIT_MASK(32) && !(gfp & GFP_DMA))
+	if (dev->coherent_dma_mask <= DMA_BIT_MASK(32) && !(gfp & GFP_DMA))
 		gfp |= GFP_DMA32;
 #endif
        return gfp;
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index df7ab02f959f..b59820872ec7 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -80,13 +80,10 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 				 dma_addr_t *dma_addr, gfp_t flag,
 				 unsigned long attrs)
 {
-	unsigned long dma_mask;
 	struct page *page;
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	dma_addr_t addr;
 
-	dma_mask = dma_alloc_coherent_mask(dev, flag);
-
 again:
 	page = NULL;
 	/* CMA can be used only in the context which permits sleeping */
@@ -95,7 +92,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 						 flag);
 		if (page) {
 			addr = phys_to_dma(dev, page_to_phys(page));
-			if (addr + size > dma_mask) {
+			if (addr + size > dev->coherent_dma_mask) {
 				dma_release_from_contiguous(dev, page, count);
 				page = NULL;
 			}
@@ -108,10 +105,11 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 		return NULL;
 
 	addr = phys_to_dma(dev, page_to_phys(page));
-	if (addr + size > dma_mask) {
+	if (addr + size > dev->coherent_dma_mask) {
 		__free_pages(page, get_order(size));
 
-		if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {
+		if (dev->coherent_dma_mask < DMA_BIT_MASK(32) &&
+		    !(flag & GFP_DMA)) {
 			flag = (flag & ~GFP_DMA32) | GFP_DMA;
 			goto again;
 		}
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 1a53071e2e17..75dc8b525c12 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -203,12 +203,10 @@ void __init sme_early_init(void)
 static void *sev_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		       gfp_t gfp, unsigned long attrs)
 {
-	unsigned long dma_mask;
 	unsigned int order;
 	struct page *page;
 	void *vaddr = NULL;
 
-	dma_mask = dma_alloc_coherent_mask(dev, gfp);
 	order = get_order(size);
 
 	/*
@@ -226,7 +224,7 @@ static void *sev_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		 * mask with it already cleared.
 		 */
 		addr = __sme_clr(phys_to_dma(dev, page_to_phys(page)));
-		if ((addr + size) > dma_mask) {
+		if ((addr + size) > dev->coherent_dma_mask) {
 			__free_pages(page, get_order(size));
 		} else {
 			vaddr = page_address(page);
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 5bb72d3f8337..e1c60899fdbc 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -53,20 +53,6 @@
  * API.
  */
 
-#ifndef CONFIG_X86
-static unsigned long dma_alloc_coherent_mask(struct device *dev,
-					    gfp_t gfp)
-{
-	unsigned long dma_mask = 0;
-
-	dma_mask = dev->coherent_dma_mask;
-	if (!dma_mask)
-		dma_mask = (gfp & GFP_DMA) ? DMA_BIT_MASK(24) : DMA_BIT_MASK(32);
-
-	return dma_mask;
-}
-#endif
-
 #define XEN_SWIOTLB_ERROR_CODE	(~(dma_addr_t)0x0)
 
 static char *xen_io_tlb_start, *xen_io_tlb_end;
@@ -328,7 +314,7 @@ xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 		return ret;
 
 	if (hwdev && hwdev->coherent_dma_mask)
-		dma_mask = dma_alloc_coherent_mask(hwdev, flags);
+		dma_mask = hwdev->coherent_dma_mask;
 
 	/* At this point dma_handle is the physical address, next we are
 	 * going to set it to the machine address.
-- 
2.14.2

[PATCH 03/13] x86: use dma-direct

[Christoph Hellwig]

The generic dma-direct implementation is now functionally equivalent to
the x86 nommu dma_map implementation, so switch over to using it.

Note that the various iommu drivers are switched from x86_dma_supported
to dma_direct_supported to provide identical functionality, although the
checks looks fairly questionable for at least some of them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/Kconfig                   |  1 +
 arch/x86/include/asm/dma-mapping.h |  8 -----
 arch/x86/include/asm/iommu.h       |  3 --
 arch/x86/kernel/Makefile           |  2 +-
 arch/x86/kernel/amd_gart_64.c      |  7 ++--
 arch/x86/kernel/pci-calgary_64.c   |  3 +-
 arch/x86/kernel/pci-dma.c          | 66 +-------------------------------------
 arch/x86/kernel/pci-swiotlb.c      |  5 ++-
 arch/x86/pci/sta2x11-fixup.c       |  2 +-
 drivers/iommu/amd_iommu.c          |  7 ++--
 drivers/iommu/intel-iommu.c        |  3 +-
 11 files changed, 17 insertions(+), 90 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c1236b187824..7272bb3768d7 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -83,6 +83,7 @@ config X86
 	select CLOCKSOURCE_VALIDATE_LAST_CYCLE
 	select CLOCKSOURCE_WATCHDOG
 	select DCACHE_WORD_ACCESS
+	select DMA_DIRECT_OPS
 	select EDAC_ATOMIC_SCRUB
 	select EDAC_SUPPORT
 	select GENERIC_CLOCKEVENTS
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 545bf3721bc0..df9816b385eb 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -36,14 +36,6 @@ int arch_dma_supported(struct device *dev, u64 mask);
 bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp);
 #define arch_dma_alloc_attrs arch_dma_alloc_attrs
 
-extern void *dma_generic_alloc_coherent(struct device *dev, size_t size,
-					dma_addr_t *dma_addr, gfp_t flag,
-					unsigned long attrs);
-
-extern void dma_generic_free_coherent(struct device *dev, size_t size,
-				      void *vaddr, dma_addr_t dma_addr,
-				      unsigned long attrs);
-
 static inline gfp_t dma_alloc_coherent_gfp_flags(struct device *dev, gfp_t gfp)
 {
 	if (dev->coherent_dma_mask <= DMA_BIT_MASK(24))
diff --git a/arch/x86/include/asm/iommu.h b/arch/x86/include/asm/iommu.h
index 1e5d5d92eb40..baedab8ac538 100644
--- a/arch/x86/include/asm/iommu.h
+++ b/arch/x86/include/asm/iommu.h
@@ -2,13 +2,10 @@
 #ifndef _ASM_X86_IOMMU_H
 #define _ASM_X86_IOMMU_H
 
-extern const struct dma_map_ops nommu_dma_ops;
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
 extern int iommu_pass_through;
 
-int x86_dma_supported(struct device *dev, u64 mask);
-
 /* 10 seconds */
 #define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
 
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 29786c87e864..2e8c8a09ecab 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -57,7 +57,7 @@ obj-$(CONFIG_X86_ESPFIX64)	+= espfix_64.o
 obj-$(CONFIG_SYSFS)	+= ksysfs.o
 obj-y			+= bootflag.o e820.o
 obj-y			+= pci-dma.o quirks.o topology.o kdebugfs.o
-obj-y			+= alternative.o i8253.o pci-nommu.o hw_breakpoint.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
diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index ecd486cb06ab..52e3abcf3e70 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -501,8 +501,7 @@ gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
 		}
 		__free_pages(page, get_order(size));
 	} else
-		return dma_generic_alloc_coherent(dev, size, dma_addr, flag,
-						  attrs);
+		return dma_direct_alloc(dev, size, dma_addr, flag, attrs);
 
 	return NULL;
 }
@@ -513,7 +512,7 @@ gart_free_coherent(struct device *dev, size_t size, void *vaddr,
 		   dma_addr_t dma_addr, unsigned long attrs)
 {
 	gart_unmap_page(dev, dma_addr, size, DMA_BIDIRECTIONAL, 0);
-	dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
+	dma_direct_free(dev, size, vaddr, dma_addr, attrs);
 }
 
 static int gart_mapping_error(struct device *dev, dma_addr_t dma_addr)
@@ -705,7 +704,7 @@ static const struct dma_map_ops gart_dma_ops = {
 	.alloc				= gart_alloc_coherent,
 	.free				= gart_free_coherent,
 	.mapping_error			= gart_mapping_error,
-	.dma_supported			= x86_dma_supported,
+	.dma_supported			= dma_direct_supported,
 };
 
 static void gart_iommu_shutdown(void)
diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index 35c461f21815..5647853053bd 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -33,6 +33,7 @@
 #include <linux/string.h>
 #include <linux/crash_dump.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma-direct.h>
 #include <linux/bitmap.h>
 #include <linux/pci_ids.h>
 #include <linux/pci.h>
@@ -493,7 +494,7 @@ static const struct dma_map_ops calgary_dma_ops = {
 	.map_page = calgary_map_page,
 	.unmap_page = calgary_unmap_page,
 	.mapping_error = calgary_mapping_error,
-	.dma_supported = x86_dma_supported,
+	.dma_supported = dma_direct_supported,
 };
 
 static inline void __iomem * busno_to_bbar(unsigned char num)
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index b59820872ec7..db0b88ea8d1b 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -18,7 +18,7 @@
 
 static int forbid_dac __read_mostly;
 
-const struct dma_map_ops *dma_ops = &nommu_dma_ops;
+const struct dma_map_ops *dma_ops = &dma_direct_ops;
 EXPORT_SYMBOL(dma_ops);
 
 static int iommu_sac_force __read_mostly;
@@ -76,60 +76,6 @@ void __init pci_iommu_alloc(void)
 		}
 	}
 }
-void *dma_generic_alloc_coherent(struct device *dev, size_t size,
-				 dma_addr_t *dma_addr, gfp_t flag,
-				 unsigned long attrs)
-{
-	struct page *page;
-	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-	dma_addr_t addr;
-
-again:
-	page = NULL;
-	/* CMA can be used only in the context which permits sleeping */
-	if (gfpflags_allow_blocking(flag)) {
-		page = dma_alloc_from_contiguous(dev, count, get_order(size),
-						 flag);
-		if (page) {
-			addr = phys_to_dma(dev, page_to_phys(page));
-			if (addr + size > dev->coherent_dma_mask) {
-				dma_release_from_contiguous(dev, page, count);
-				page = NULL;
-			}
-		}
-	}
-	/* fallback */
-	if (!page)
-		page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
-	if (!page)
-		return NULL;
-
-	addr = phys_to_dma(dev, page_to_phys(page));
-	if (addr + size > dev->coherent_dma_mask) {
-		__free_pages(page, get_order(size));
-
-		if (dev->coherent_dma_mask < DMA_BIT_MASK(32) &&
-		    !(flag & GFP_DMA)) {
-			flag = (flag & ~GFP_DMA32) | GFP_DMA;
-			goto again;
-		}
-
-		return NULL;
-	}
-	memset(page_address(page), 0, size);
-	*dma_addr = addr;
-	return page_address(page);
-}
-
-void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
-			       dma_addr_t dma_addr, unsigned long attrs)
-{
-	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-	struct page *page = virt_to_page(vaddr);
-
-	if (!dma_release_from_contiguous(dev, page, count))
-		free_pages((unsigned long)vaddr, get_order(size));
-}
 
 bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp)
 {
@@ -243,16 +189,6 @@ int arch_dma_supported(struct device *dev, u64 mask)
 }
 EXPORT_SYMBOL(arch_dma_supported);
 
-int x86_dma_supported(struct device *dev, u64 mask)
-{
-	/* Copied from i386. Doesn't make much sense, because it will
-	   only work for pci_alloc_coherent.
-	   The caller just has to use GFP_DMA in this case. */
-	if (mask < DMA_BIT_MASK(24))
-		return 0;
-	return 1;
-}
-
 static int __init pci_iommu_init(void)
 {
 	struct iommu_table_entry *p;
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index 0ee0f8f34251..bcb6a9bf64ad 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -30,8 +30,7 @@ void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 	 */
 	flags |= __GFP_NOWARN;
 
-	vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags,
-					   attrs);
+	vaddr = dma_direct_alloc(hwdev, size, dma_handle, flags, attrs);
 	if (vaddr)
 		return vaddr;
 
@@ -45,7 +44,7 @@ void x86_swiotlb_free_coherent(struct device *dev, size_t size,
 	if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
 		swiotlb_free_coherent(dev, size, vaddr, dma_addr);
 	else
-		dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
+		dma_direct_free(dev, size, vaddr, dma_addr, attrs);
 }
 
 static const struct dma_map_ops x86_swiotlb_dma_ops = {
diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
index 75577c1490c4..6c712fe11bdc 100644
--- a/arch/x86/pci/sta2x11-fixup.c
+++ b/arch/x86/pci/sta2x11-fixup.c
@@ -193,7 +193,7 @@ static const struct dma_map_ops sta2x11_dma_ops = {
 	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
 	.sync_sg_for_device = swiotlb_sync_sg_for_device,
 	.mapping_error = swiotlb_dma_mapping_error,
-	.dma_supported = x86_dma_supported,
+	.dma_supported = dma_direct_supported,
 };
 
 /* At setup time, we use our own ops if the device is a ConneXt one */
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 74788fdeb773..0bf19423b588 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -28,6 +28,7 @@
 #include <linux/debugfs.h>
 #include <linux/scatterlist.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma-direct.h>
 #include <linux/iommu-helper.h>
 #include <linux/iommu.h>
 #include <linux/delay.h>
@@ -2193,7 +2194,7 @@ static int amd_iommu_add_device(struct device *dev)
 				dev_name(dev));
 
 		iommu_ignore_device(dev);
-		dev->dma_ops = &nommu_dma_ops;
+		dev->dma_ops = &dma_direct_ops;
 		goto out;
 	}
 	init_iommu_group(dev);
@@ -2680,7 +2681,7 @@ static void free_coherent(struct device *dev, size_t size,
  */
 static int amd_iommu_dma_supported(struct device *dev, u64 mask)
 {
-	if (!x86_dma_supported(dev, mask))
+	if (!dma_direct_supported(dev, mask))
 		return 0;
 	return check_device(dev);
 }
@@ -2794,7 +2795,7 @@ int __init amd_iommu_init_dma_ops(void)
 	 * continue to be SWIOTLB.
 	 */
 	if (!swiotlb)
-		dma_ops = &nommu_dma_ops;
+		dma_ops = &dma_direct_ops;
 
 	if (amd_iommu_unmap_flush)
 		pr_info("AMD-Vi: IO/TLB flush on unmap enabled\n");
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 582fd01cb7d1..fd899b2a12bb 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -45,6 +45,7 @@
 #include <linux/pci-ats.h>
 #include <linux/memblock.h>
 #include <linux/dma-contiguous.h>
+#include <linux/dma-direct.h>
 #include <linux/crash_dump.h>
 #include <asm/irq_remapping.h>
 #include <asm/cacheflush.h>
@@ -3871,7 +3872,7 @@ const struct dma_map_ops intel_dma_ops = {
 	.unmap_page = intel_unmap_page,
 	.mapping_error = intel_mapping_error,
 #ifdef CONFIG_X86
-	.dma_supported = x86_dma_supported,
+	.dma_supported = dma_direct_supported,
 #endif
 };
 
-- 
2.14.2

[PATCH 04/13] x86: use generic swiotlb_ops

[Christoph Hellwig]

The generic swiotlb dma ops were based on the x86 ones and provide
equivalent functionality, so use them.

Also fix the sta2x11 case.  For that SOC the dma map ops need an
additional physical to dma address translations.  For swiotlb buffers
that is done throught the phys_to_dma helper, but the sta2x11_dma_ops
also added an additional translation on the return value from
x86_swiotlb_alloc_coherent, which is only correct if that functions
returns a direct allocation and not a swiotlb buffer.  With the
generic swiotlb and dma-direct code phys_to_dma is not always used
and the separate sta2x11_dma_ops can be replaced with a simple
bit that marks if the additional physical to dma address translation
is needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/include/asm/device.h  |  3 +++
 arch/x86/include/asm/swiotlb.h |  8 -------
 arch/x86/kernel/pci-swiotlb.c  | 47 +-----------------------------------------
 arch/x86/pci/sta2x11-fixup.c   | 46 +++++------------------------------------
 4 files changed, 9 insertions(+), 95 deletions(-)

diff --git a/arch/x86/include/asm/device.h b/arch/x86/include/asm/device.h
index 5e12c63b47aa..812bd6c5d602 100644
--- a/arch/x86/include/asm/device.h
+++ b/arch/x86/include/asm/device.h
@@ -6,6 +6,9 @@ struct dev_archdata {
 #if defined(CONFIG_INTEL_IOMMU) || defined(CONFIG_AMD_IOMMU)
 	void *iommu; /* hook for IOMMU specific extension */
 #endif
+#ifdef CONFIG_STA2X11
+	bool is_sta2x11 : 1;
+#endif
 };
 
 #if defined(CONFIG_X86_DEV_DMA_OPS) && defined(CONFIG_PCI_DOMAINS)
diff --git a/arch/x86/include/asm/swiotlb.h b/arch/x86/include/asm/swiotlb.h
index 1c6a6cb230ff..ff6c92eff035 100644
--- a/arch/x86/include/asm/swiotlb.h
+++ b/arch/x86/include/asm/swiotlb.h
@@ -27,12 +27,4 @@ static inline void pci_swiotlb_late_init(void)
 {
 }
 #endif
-
-extern void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
-					dma_addr_t *dma_handle, gfp_t flags,
-					unsigned long attrs);
-extern void x86_swiotlb_free_coherent(struct device *dev, size_t size,
-					void *vaddr, dma_addr_t dma_addr,
-					unsigned long attrs);
-
 #endif /* _ASM_X86_SWIOTLB_H */
diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index bcb6a9bf64ad..661583662430 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -17,51 +17,6 @@
 
 int swiotlb __read_mostly;
 
-void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
-					dma_addr_t *dma_handle, gfp_t flags,
-					unsigned long attrs)
-{
-	void *vaddr;
-
-	/*
-	 * Don't print a warning when the first allocation attempt fails.
-	 * swiotlb_alloc_coherent() will print a warning when the DMA
-	 * memory allocation ultimately failed.
-	 */
-	flags |= __GFP_NOWARN;
-
-	vaddr = dma_direct_alloc(hwdev, size, dma_handle, flags, attrs);
-	if (vaddr)
-		return vaddr;
-
-	return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
-}
-
-void x86_swiotlb_free_coherent(struct device *dev, size_t size,
-				      void *vaddr, dma_addr_t dma_addr,
-				      unsigned long attrs)
-{
-	if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
-		swiotlb_free_coherent(dev, size, vaddr, dma_addr);
-	else
-		dma_direct_free(dev, size, vaddr, dma_addr, attrs);
-}
-
-static const struct dma_map_ops x86_swiotlb_dma_ops = {
-	.mapping_error = swiotlb_dma_mapping_error,
-	.alloc = x86_swiotlb_alloc_coherent,
-	.free = x86_swiotlb_free_coherent,
-	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
-	.sync_single_for_device = swiotlb_sync_single_for_device,
-	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
-	.sync_sg_for_device = swiotlb_sync_sg_for_device,
-	.map_sg = swiotlb_map_sg_attrs,
-	.unmap_sg = swiotlb_unmap_sg_attrs,
-	.map_page = swiotlb_map_page,
-	.unmap_page = swiotlb_unmap_page,
-	.dma_supported = NULL,
-};
-
 /*
  * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
  *
@@ -111,7 +66,7 @@ void __init pci_swiotlb_init(void)
 {
 	if (swiotlb) {
 		swiotlb_init(0);
-		dma_ops = &x86_swiotlb_dma_ops;
+		dma_ops = &swiotlb_dma_ops;
 	}
 }
 
diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
index 6c712fe11bdc..eac58e03f43c 100644
--- a/arch/x86/pci/sta2x11-fixup.c
+++ b/arch/x86/pci/sta2x11-fixup.c
@@ -159,43 +159,6 @@ static dma_addr_t a2p(dma_addr_t a, struct pci_dev *pdev)
 	return p;
 }
 
-/**
- * sta2x11_swiotlb_alloc_coherent - Allocate swiotlb bounce buffers
- *     returns virtual address. This is the only "special" function here.
- * @dev: PCI device
- * @size: Size of the buffer
- * @dma_handle: DMA address
- * @flags: memory flags
- */
-static void *sta2x11_swiotlb_alloc_coherent(struct device *dev,
-					    size_t size,
-					    dma_addr_t *dma_handle,
-					    gfp_t flags,
-					    unsigned long attrs)
-{
-	void *vaddr;
-
-	vaddr = x86_swiotlb_alloc_coherent(dev, size, dma_handle, flags, attrs);
-	*dma_handle = p2a(*dma_handle, to_pci_dev(dev));
-	return vaddr;
-}
-
-/* We have our own dma_ops: the same as swiotlb but from alloc (above) */
-static const struct dma_map_ops sta2x11_dma_ops = {
-	.alloc = sta2x11_swiotlb_alloc_coherent,
-	.free = x86_swiotlb_free_coherent,
-	.map_page = swiotlb_map_page,
-	.unmap_page = swiotlb_unmap_page,
-	.map_sg = swiotlb_map_sg_attrs,
-	.unmap_sg = swiotlb_unmap_sg_attrs,
-	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
-	.sync_single_for_device = swiotlb_sync_single_for_device,
-	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
-	.sync_sg_for_device = swiotlb_sync_sg_for_device,
-	.mapping_error = swiotlb_dma_mapping_error,
-	.dma_supported = dma_direct_supported,
-};
-
 /* At setup time, we use our own ops if the device is a ConneXt one */
 static void sta2x11_setup_pdev(struct pci_dev *pdev)
 {
@@ -205,7 +168,8 @@ static void sta2x11_setup_pdev(struct pci_dev *pdev)
 		return;
 	pci_set_consistent_dma_mask(pdev, STA2X11_AMBA_SIZE - 1);
 	pci_set_dma_mask(pdev, STA2X11_AMBA_SIZE - 1);
-	pdev->dev.dma_ops = &sta2x11_dma_ops;
+	pdev->dev.dma_ops = &swiotlb_dma_ops;
+	pdev->dev.archdata.is_sta2x11 = true;
 
 	/* We must enable all devices as master, for audio DMA to work */
 	pci_set_master(pdev);
@@ -225,7 +189,7 @@ bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
 {
 	struct sta2x11_mapping *map;
 
-	if (dev->dma_ops != &sta2x11_dma_ops) {
+	if (!dev->archdata.is_sta2x11) {
 		if (!dev->dma_mask)
 			return false;
 		return addr + size - 1 <= *dev->dma_mask;
@@ -249,7 +213,7 @@ bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
  */
 dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
-	if (dev->dma_ops != &sta2x11_dma_ops)
+	if (!dev->archdata.is_sta2x11)
 		return paddr;
 	return p2a(paddr, to_pci_dev(dev));
 }
@@ -261,7 +225,7 @@ dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
  */
 phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
 {
-	if (dev->dma_ops != &sta2x11_dma_ops)
+	if (!dev->archdata.is_sta2x11)
 		return daddr;
 	return a2p(daddr, to_pci_dev(dev));
 }
-- 
2.14.2

[PATCH 05/13] x86/amd_gart: look at coherent_dma_mask instead of GFP_DMA

[Christoph Hellwig]

We want to phase out looking at the magic GFP_DMA flag in the dma mapping
routines, so switch the gart driver to use the coherent_dma_mask instead,
which is used to select the GFP_DMA flag in the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/kernel/amd_gart_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index 52e3abcf3e70..79ac6caaaabb 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -484,7 +484,7 @@ gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
 	unsigned long align_mask;
 	struct page *page;
 
-	if (force_iommu && !(flag & GFP_DMA)) {
+	if (force_iommu && dev->coherent_dma_mask > DMA_BIT_MASK(24)) {
 		flag &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
 		page = alloc_pages(flag | __GFP_ZERO, get_order(size));
 		if (!page)
-- 
2.14.2

[PATCH 06/13] x86/amd_gart: use dma_direct_{alloc,free}

[Christoph Hellwig]

This gains support for CMA allocations for the force_iommu case, and
cleans up the code a bit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/kernel/amd_gart_64.c | 36 ++++++++++++++----------------------
 1 file changed, 14 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index 79ac6caaaabb..f299d8a479bb 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -480,29 +480,21 @@ static void *
 gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
 		    gfp_t flag, unsigned long attrs)
 {
-	dma_addr_t paddr;
-	unsigned long align_mask;
-	struct page *page;
-
-	if (force_iommu && dev->coherent_dma_mask > DMA_BIT_MASK(24)) {
-		flag &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
-		page = alloc_pages(flag | __GFP_ZERO, get_order(size));
-		if (!page)
-			return NULL;
-
-		align_mask = (1UL << get_order(size)) - 1;
-		paddr = dma_map_area(dev, page_to_phys(page), size,
-				     DMA_BIDIRECTIONAL, align_mask);
-
-		flush_gart();
-		if (paddr != bad_dma_addr) {
-			*dma_addr = paddr;
-			return page_address(page);
-		}
-		__free_pages(page, get_order(size));
-	} else
-		return dma_direct_alloc(dev, size, dma_addr, flag, attrs);
+	void *vaddr;
+
+	vaddr = dma_direct_alloc(dev, size, dma_addr, flag, attrs);
+	if (!vaddr ||
+	    !force_iommu || dev->coherent_dma_mask <= DMA_BIT_MASK(24))
+		return vaddr;
 
+	*dma_addr = dma_map_area(dev, virt_to_phys(vaddr), size,
+			DMA_BIDIRECTIONAL, (1UL << get_order(size)) - 1);
+	flush_gart();
+	if (unlikely(*dma_addr == bad_dma_addr))
+		goto out_free;
+	return vaddr;
+out_free:
+	dma_direct_free(dev, size, vaddr, *dma_addr, attrs);
 	return NULL;
 }
 
-- 
2.14.2

[PATCH 07/13] iommu/amd_iommu: use dma_direct_{alloc,free}

[Christoph Hellwig]

This cleans up the code a lot by removing duplicate logic.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/iommu/Kconfig     |  1 +
 drivers/iommu/amd_iommu.c | 68 +++++++++++++++--------------------------------
 2 files changed, 22 insertions(+), 47 deletions(-)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index f3a21343e636..dc7c1914645d 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -107,6 +107,7 @@ config IOMMU_PGTABLES_L2
 # AMD IOMMU support
 config AMD_IOMMU
 	bool "AMD IOMMU support"
+	select DMA_DIRECT_OPS
 	select SWIOTLB
 	select PCI_MSI
 	select PCI_ATS
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 0bf19423b588..83819d0cbf90 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -2600,51 +2600,32 @@ static void *alloc_coherent(struct device *dev, size_t size,
 			    unsigned long attrs)
 {
 	u64 dma_mask = dev->coherent_dma_mask;
-	struct protection_domain *domain;
-	struct dma_ops_domain *dma_dom;
-	struct page *page;
-
-	domain = get_domain(dev);
-	if (PTR_ERR(domain) == -EINVAL) {
-		page = alloc_pages(flag, get_order(size));
-		*dma_addr = page_to_phys(page);
-		return page_address(page);
-	} else if (IS_ERR(domain))
-		return NULL;
+	struct protection_domain *domain = get_domain(dev);
+	bool is_direct = false;
+	void *virt_addr;
 
-	dma_dom   = to_dma_ops_domain(domain);
-	size	  = PAGE_ALIGN(size);
-	dma_mask  = dev->coherent_dma_mask;
-	flag     &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
-	flag     |= __GFP_ZERO;
-
-	page = alloc_pages(flag | __GFP_NOWARN,  get_order(size));
-	if (!page) {
-		if (!gfpflags_allow_blocking(flag))
-			return NULL;
-
-		page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
-						 get_order(size), flag);
-		if (!page)
+	if (IS_ERR(domain)) {
+		if (PTR_ERR(domain) != -EINVAL)
 			return NULL;
+		is_direct = true;
 	}
 
+	virt_addr = dma_direct_alloc(dev, size, dma_addr, flag, attrs);
+	if (!virt_addr || is_direct)
+		return virt_addr;
+
 	if (!dma_mask)
 		dma_mask = *dev->dma_mask;
 
-	*dma_addr = __map_single(dev, dma_dom, page_to_phys(page),
-				 size, DMA_BIDIRECTIONAL, dma_mask);
-
+	*dma_addr = __map_single(dev, to_dma_ops_domain(domain),
+			virt_to_phys(virt_addr), PAGE_ALIGN(size),
+			DMA_BIDIRECTIONAL, dma_mask);
 	if (*dma_addr == AMD_IOMMU_MAPPING_ERROR)
 		goto out_free;
-
-	return page_address(page);
+	return virt_addr;
 
 out_free:
-
-	if (!dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT))
-		__free_pages(page, get_order(size));
-
+	dma_direct_free(dev, size, virt_addr, *dma_addr, attrs);
 	return NULL;
 }
 
@@ -2655,24 +2636,17 @@ static void free_coherent(struct device *dev, size_t size,
 			  void *virt_addr, dma_addr_t dma_addr,
 			  unsigned long attrs)
 {
-	struct protection_domain *domain;
-	struct dma_ops_domain *dma_dom;
-	struct page *page;
+	struct protection_domain *domain = get_domain(dev);
 
-	page = virt_to_page(virt_addr);
 	size = PAGE_ALIGN(size);
 
-	domain = get_domain(dev);
-	if (IS_ERR(domain))
-		goto free_mem;
+	if (!IS_ERR(domain)) {
+		struct dma_ops_domain *dma_dom = to_dma_ops_domain(domain);
 
-	dma_dom = to_dma_ops_domain(domain);
-
-	__unmap_single(dma_dom, dma_addr, size, DMA_BIDIRECTIONAL);
+		__unmap_single(dma_dom, dma_addr, size, DMA_BIDIRECTIONAL);
+	}
 
-free_mem:
-	if (!dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT))
-		__free_pages(page, get_order(size));
+	dma_direct_free(dev, size, virt_addr, dma_addr, attrs);
 }
 
 /*
-- 
2.14.2

[PATCH 08/13] iommu/intel-iommu: cleanup intel_{alloc,free}_coherent

[Christoph Hellwig]

Use the dma_direct_* helpers and cleanup the code flow.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/iommu/Kconfig       |  1 +
 drivers/iommu/intel-iommu.c | 62 ++++++++++++---------------------------------
 2 files changed, 17 insertions(+), 46 deletions(-)

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index dc7c1914645d..df171cb85822 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -143,6 +143,7 @@ config DMAR_TABLE
 config INTEL_IOMMU
 	bool "Support for Intel IOMMU using DMA Remapping Devices"
 	depends on PCI_MSI && ACPI && (X86 || IA64_GENERIC)
+	select DMA_DIRECT_OPS
 	select IOMMU_API
 	select IOMMU_IOVA
 	select DMAR_TABLE
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index fd899b2a12bb..24d1b1b42013 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -31,6 +31,7 @@
 #include <linux/pci.h>
 #include <linux/dmar.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma-direct.h>
 #include <linux/mempool.h>
 #include <linux/memory.h>
 #include <linux/cpu.h>
@@ -3708,61 +3709,30 @@ static void *intel_alloc_coherent(struct device *dev, size_t size,
 				  dma_addr_t *dma_handle, gfp_t flags,
 				  unsigned long attrs)
 {
-	struct page *page = NULL;
-	int order;
-
-	size = PAGE_ALIGN(size);
-	order = get_order(size);
-
-	if (!iommu_no_mapping(dev))
-		flags &= ~(GFP_DMA | GFP_DMA32);
-	else if (dev->coherent_dma_mask < dma_get_required_mask(dev)) {
-		if (dev->coherent_dma_mask < DMA_BIT_MASK(32))
-			flags |= GFP_DMA;
-		else
-			flags |= GFP_DMA32;
-	}
+	void *vaddr;
 
-	if (gfpflags_allow_blocking(flags)) {
-		unsigned int count = size >> PAGE_SHIFT;
+	vaddr = dma_direct_alloc(dev, size, dma_handle, flags, attrs);
+	if (iommu_no_mapping(dev) || !vaddr)
+		return vaddr;
 
-		page = dma_alloc_from_contiguous(dev, count, order, flags);
-		if (page && iommu_no_mapping(dev) &&
-		    page_to_phys(page) + size > dev->coherent_dma_mask) {
-			dma_release_from_contiguous(dev, page, count);
-			page = NULL;
-		}
-	}
-
-	if (!page)
-		page = alloc_pages(flags, order);
-	if (!page)
-		return NULL;
-	memset(page_address(page), 0, size);
-
-	*dma_handle = __intel_map_single(dev, page_to_phys(page), size,
-					 DMA_BIDIRECTIONAL,
-					 dev->coherent_dma_mask);
-	if (*dma_handle)
-		return page_address(page);
-	if (!dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT))
-		__free_pages(page, order);
+	*dma_handle = __intel_map_single(dev, virt_to_phys(vaddr),
+			PAGE_ALIGN(size), DMA_BIDIRECTIONAL,
+			dev->coherent_dma_mask);
+	if (!*dma_handle)
+		goto out_free_pages;
+	return vaddr;
 
+out_free_pages:
+	dma_direct_free(dev, size, vaddr, *dma_handle, attrs);
 	return NULL;
 }
 
 static void intel_free_coherent(struct device *dev, size_t size, void *vaddr,
 				dma_addr_t dma_handle, unsigned long attrs)
 {
-	int order;
-	struct page *page = virt_to_page(vaddr);
-
-	size = PAGE_ALIGN(size);
-	order = get_order(size);
-
-	intel_unmap(dev, dma_handle, size);
-	if (!dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT))
-		__free_pages(page, order);
+	if (!iommu_no_mapping(dev))
+		intel_unmap(dev, dma_handle, PAGE_ALIGN(size));
+	dma_direct_free(dev, size, vaddr, dma_handle, attrs);
 }
 
 static void intel_unmap_sg(struct device *dev, struct scatterlist *sglist,
-- 
2.14.2

[PATCH 09/13] x86: remove dma_alloc_coherent_gfp_flags

[Christoph Hellwig]

All dma_ops implementations used on x86 now take care of setting their own
required GFP_ masks for the allocation.  And given that the common code
now clears harmful flags itself that means we can stop the flags in all
the iommu implementations as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/include/asm/dma-mapping.h | 11 -----------
 arch/x86/kernel/pci-calgary_64.c   |  2 --
 arch/x86/kernel/pci-dma.c          |  2 --
 arch/x86/mm/mem_encrypt.c          |  7 -------
 4 files changed, 22 deletions(-)

diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index df9816b385eb..89ce4bfd241f 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -36,15 +36,4 @@ int arch_dma_supported(struct device *dev, u64 mask);
 bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp);
 #define arch_dma_alloc_attrs arch_dma_alloc_attrs
 
-static inline gfp_t dma_alloc_coherent_gfp_flags(struct device *dev, gfp_t gfp)
-{
-	if (dev->coherent_dma_mask <= DMA_BIT_MASK(24))
-		gfp |= GFP_DMA;
-#ifdef CONFIG_X86_64
-	if (dev->coherent_dma_mask <= DMA_BIT_MASK(32) && !(gfp & GFP_DMA))
-		gfp |= GFP_DMA32;
-#endif
-       return gfp;
-}
-
 #endif
diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index 5647853053bd..bbfc8b1e9104 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -446,8 +446,6 @@ static void* calgary_alloc_coherent(struct device *dev, size_t size,
 	npages = size >> PAGE_SHIFT;
 	order = get_order(size);
 
-	flag &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
-
 	/* alloc enough pages (and possibly more) */
 	ret = (void *)__get_free_pages(flag, order);
 	if (!ret)
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index db0b88ea8d1b..14437116ffea 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -82,8 +82,6 @@ bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp)
 	if (!*dev)
 		*dev = &x86_dma_fallback_dev;
 
-	*gfp = dma_alloc_coherent_gfp_flags(*dev, *gfp);
-
 	if (!is_device_dma_capable(*dev))
 		return false;
 	return true;
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 75dc8b525c12..66beedc8fe3d 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -208,13 +208,6 @@ static void *sev_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	void *vaddr = NULL;
 
 	order = get_order(size);
-
-	/*
-	 * Memory will be memset to zero after marking decrypted, so don't
-	 * bother clearing it before.
-	 */
-	gfp &= ~__GFP_ZERO;
-
 	page = alloc_pages_node(dev_to_node(dev), gfp, order);
 	if (page) {
 		dma_addr_t addr;
-- 
2.14.2

[PATCH 10/13] set_memory.h: provide set_memory_{en,de}crypted stubs

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/set_memory.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
index e5140648f638..da5178216da5 100644
--- a/include/linux/set_memory.h
+++ b/include/linux/set_memory.h
@@ -17,4 +17,16 @@ static inline int set_memory_x(unsigned long addr,  int numpages) { return 0; }
 static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
 #endif
 
+#ifndef CONFIG_ARCH_HAS_MEM_ENCRYPT
+static inline int set_memory_encrypted(unsigned long addr, int numpages)
+{
+	return 0;
+}
+
+static inline int set_memory_decrypted(unsigned long addr, int numpages)
+{
+	return 0;
+}
+#endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */
+
 #endif /* _LINUX_SET_MEMORY_H_ */
-- 
2.14.2

[PATCH 11/13] dma-direct: handle the memory encryption bit in common code

[Christoph Hellwig]

Give the basic phys_to_dma and dma_to_phys helpers a __-prefix and add
the memory encryption mask to the non-prefixed versions.  Use the
__-prefixed versions directly instead of clearing the mask again in
various places.

With that in place the generic dma-direct routines can be used to
allocate non-encrypted bounce buffers, and the x86 SEV case can use
the generic swiotlb ops.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/arm/include/asm/dma-direct.h                  |  4 +-
 arch/mips/cavium-octeon/dma-octeon.c               | 10 +--
 .../include/asm/mach-cavium-octeon/dma-coherence.h |  4 +-
 .../include/asm/mach-loongson64/dma-coherence.h    | 10 +--
 arch/mips/loongson64/common/dma-swiotlb.c          |  4 +-
 arch/powerpc/include/asm/dma-direct.h              |  4 +-
 arch/x86/Kconfig                                   |  2 +-
 arch/x86/include/asm/dma-direct.h                  | 25 +-------
 arch/x86/mm/mem_encrypt.c                          | 73 +---------------------
 arch/x86/pci/sta2x11-fixup.c                       |  6 +-
 include/linux/dma-direct.h                         | 21 ++++++-
 lib/dma-direct.c                                   | 21 +++++--
 lib/swiotlb.c                                      | 25 +++-----
 13 files changed, 70 insertions(+), 139 deletions(-)

diff --git a/arch/arm/include/asm/dma-direct.h b/arch/arm/include/asm/dma-direct.h
index 5b0a8a421894..b67e5fc1fe43 100644
--- a/arch/arm/include/asm/dma-direct.h
+++ b/arch/arm/include/asm/dma-direct.h
@@ -2,13 +2,13 @@
 #ifndef ASM_ARM_DMA_DIRECT_H
 #define ASM_ARM_DMA_DIRECT_H 1
 
-static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
 	unsigned int offset = paddr & ~PAGE_MASK;
 	return pfn_to_dma(dev, __phys_to_pfn(paddr)) + offset;
 }
 
-static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
+static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr)
 {
 	unsigned int offset = dev_addr & ~PAGE_MASK;
 	return __pfn_to_phys(dma_to_pfn(dev, dev_addr)) + offset;
diff --git a/arch/mips/cavium-octeon/dma-octeon.c b/arch/mips/cavium-octeon/dma-octeon.c
index c7bb8a407041..7b335ab21697 100644
--- a/arch/mips/cavium-octeon/dma-octeon.c
+++ b/arch/mips/cavium-octeon/dma-octeon.c
@@ -10,7 +10,7 @@
  * IP32 changes by Ilya.
  * Copyright (C) 2010 Cavium Networks, Inc.
  */
-#include <linux/dma-mapping.h>
+#include <linux/dma-direct.h>
 #include <linux/scatterlist.h>
 #include <linux/bootmem.h>
 #include <linux/export.h>
@@ -182,7 +182,7 @@ struct octeon_dma_map_ops {
 	phys_addr_t (*dma_to_phys)(struct device *dev, dma_addr_t daddr);
 };
 
-dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
 	struct octeon_dma_map_ops *ops = container_of(get_dma_ops(dev),
 						      struct octeon_dma_map_ops,
@@ -190,9 +190,9 @@ dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
 
 	return ops->phys_to_dma(dev, paddr);
 }
-EXPORT_SYMBOL(phys_to_dma);
+EXPORT_SYMBOL(__phys_to_dma);
 
-phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
+phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
 {
 	struct octeon_dma_map_ops *ops = container_of(get_dma_ops(dev),
 						      struct octeon_dma_map_ops,
@@ -200,7 +200,7 @@ phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
 
 	return ops->dma_to_phys(dev, daddr);
 }
-EXPORT_SYMBOL(dma_to_phys);
+EXPORT_SYMBOL(__dma_to_phys);
 
 static struct octeon_dma_map_ops octeon_linear_dma_map_ops = {
 	.dma_map_ops = {
diff --git a/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h b/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
index 138edf6b5b48..6eb1ee548b11 100644
--- a/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
+++ b/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
@@ -69,8 +69,8 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
 	return addr + size - 1 <= *dev->dma_mask;
 }
 
-dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr);
-phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr);
+dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr);
+phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr);
 
 struct dma_map_ops;
 extern const struct dma_map_ops *octeon_pci_dma_map_ops;
diff --git a/arch/mips/include/asm/mach-loongson64/dma-coherence.h b/arch/mips/include/asm/mach-loongson64/dma-coherence.h
index b1b575f5c6c1..64fc44dec0a8 100644
--- a/arch/mips/include/asm/mach-loongson64/dma-coherence.h
+++ b/arch/mips/include/asm/mach-loongson64/dma-coherence.h
@@ -25,13 +25,13 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
 	return addr + size - 1 <= *dev->dma_mask;
 }
 
-extern dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr);
-extern phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr);
+extern dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr);
+extern phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr);
 static inline dma_addr_t plat_map_dma_mem(struct device *dev, void *addr,
 					  size_t size)
 {
 #ifdef CONFIG_CPU_LOONGSON3
-	return phys_to_dma(dev, virt_to_phys(addr));
+	return __phys_to_dma(dev, virt_to_phys(addr));
 #else
 	return virt_to_phys(addr) | 0x80000000;
 #endif
@@ -41,7 +41,7 @@ static inline dma_addr_t plat_map_dma_mem_page(struct device *dev,
 					       struct page *page)
 {
 #ifdef CONFIG_CPU_LOONGSON3
-	return phys_to_dma(dev, page_to_phys(page));
+	return __phys_to_dma(dev, page_to_phys(page));
 #else
 	return page_to_phys(page) | 0x80000000;
 #endif
@@ -51,7 +51,7 @@ static inline unsigned long plat_dma_addr_to_phys(struct device *dev,
 	dma_addr_t dma_addr)
 {
 #if defined(CONFIG_CPU_LOONGSON3) && defined(CONFIG_64BIT)
-	return dma_to_phys(dev, dma_addr);
+	return __dma_to_phys(dev, dma_addr);
 #elif defined(CONFIG_CPU_LOONGSON2F) && defined(CONFIG_64BIT)
 	return (dma_addr > 0x8fffffff) ? dma_addr : (dma_addr & 0x0fffffff);
 #else
diff --git a/arch/mips/loongson64/common/dma-swiotlb.c b/arch/mips/loongson64/common/dma-swiotlb.c
index 7bbcf89475f3..6a739f8ae110 100644
--- a/arch/mips/loongson64/common/dma-swiotlb.c
+++ b/arch/mips/loongson64/common/dma-swiotlb.c
@@ -63,7 +63,7 @@ static int loongson_dma_supported(struct device *dev, u64 mask)
 	return swiotlb_dma_supported(dev, mask);
 }
 
-dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
 	long nid;
 #ifdef CONFIG_PHYS48_TO_HT40
@@ -75,7 +75,7 @@ dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
 	return paddr;
 }
 
-phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
+phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
 {
 	long nid;
 #ifdef CONFIG_PHYS48_TO_HT40
diff --git a/arch/powerpc/include/asm/dma-direct.h b/arch/powerpc/include/asm/dma-direct.h
index a5b59c765426..7702875aabb7 100644
--- a/arch/powerpc/include/asm/dma-direct.h
+++ b/arch/powerpc/include/asm/dma-direct.h
@@ -17,12 +17,12 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
 	return addr + size - 1 <= *dev->dma_mask;
 }
 
-static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
 	return paddr + get_dma_offset(dev);
 }
 
-static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
+static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
 {
 	return daddr - get_dma_offset(dev);
 }
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7272bb3768d7..6e25ca4c86ee 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -54,7 +54,6 @@ config X86
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_KCOV			if X86_64
-	select ARCH_HAS_PHYS_TO_DMA
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
 	select ARCH_HAS_PMEM_API		if X86_64
 	select ARCH_HAS_REFCOUNT
@@ -691,6 +690,7 @@ config X86_SUPPORTS_MEMORY_FAILURE
 config STA2X11
 	bool "STA2X11 Companion Chip Support"
 	depends on X86_32_NON_STANDARD && PCI
+	select ARCH_HAS_PHYS_TO_DMA
 	select X86_DEV_DMA_OPS
 	select X86_DMA_REMAP
 	select SWIOTLB
diff --git a/arch/x86/include/asm/dma-direct.h b/arch/x86/include/asm/dma-direct.h
index 1295bc622ebe..1a19251eaac9 100644
--- a/arch/x86/include/asm/dma-direct.h
+++ b/arch/x86/include/asm/dma-direct.h
@@ -2,29 +2,8 @@
 #ifndef ASM_X86_DMA_DIRECT_H
 #define ASM_X86_DMA_DIRECT_H 1
 
-#include <linux/mem_encrypt.h>
-
-#ifdef CONFIG_X86_DMA_REMAP /* Platform code defines bridge-specific code */
 bool dma_capable(struct device *dev, dma_addr_t addr, size_t size);
-dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr);
-phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr);
-#else
-static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
-{
-	if (!dev->dma_mask)
-		return 0;
-
-	return addr + size - 1 <= *dev->dma_mask;
-}
-
-static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
-{
-	return __sme_set(paddr);
-}
+dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr);
+phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr);
 
-static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
-{
-	return __sme_clr(daddr);
-}
-#endif /* CONFIG_X86_DMA_REMAP */
 #endif /* ASM_X86_DMA_DIRECT_H */
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 66beedc8fe3d..8bfc735bbdd7 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -200,58 +200,6 @@ void __init sme_early_init(void)
 		swiotlb_force = SWIOTLB_FORCE;
 }
 
-static void *sev_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
-		       gfp_t gfp, unsigned long attrs)
-{
-	unsigned int order;
-	struct page *page;
-	void *vaddr = NULL;
-
-	order = get_order(size);
-	page = alloc_pages_node(dev_to_node(dev), gfp, order);
-	if (page) {
-		dma_addr_t addr;
-
-		/*
-		 * Since we will be clearing the encryption bit, check the
-		 * mask with it already cleared.
-		 */
-		addr = __sme_clr(phys_to_dma(dev, page_to_phys(page)));
-		if ((addr + size) > dev->coherent_dma_mask) {
-			__free_pages(page, get_order(size));
-		} else {
-			vaddr = page_address(page);
-			*dma_handle = addr;
-		}
-	}
-
-	if (!vaddr)
-		vaddr = swiotlb_alloc_coherent(dev, size, dma_handle, gfp);
-
-	if (!vaddr)
-		return NULL;
-
-	/* Clear the SME encryption bit for DMA use if not swiotlb area */
-	if (!is_swiotlb_buffer(dma_to_phys(dev, *dma_handle))) {
-		set_memory_decrypted((unsigned long)vaddr, 1 << order);
-		memset(vaddr, 0, PAGE_SIZE << order);
-		*dma_handle = __sme_clr(*dma_handle);
-	}
-
-	return vaddr;
-}
-
-static void sev_free(struct device *dev, size_t size, void *vaddr,
-		     dma_addr_t dma_handle, unsigned long attrs)
-{
-	/* Set the SME encryption bit for re-use if not swiotlb area */
-	if (!is_swiotlb_buffer(dma_to_phys(dev, dma_handle)))
-		set_memory_encrypted((unsigned long)vaddr,
-				     1 << get_order(size));
-
-	swiotlb_free_coherent(dev, size, vaddr, dma_handle);
-}
-
 static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
 {
 	pgprot_t old_prot, new_prot;
@@ -404,20 +352,6 @@ bool sev_active(void)
 }
 EXPORT_SYMBOL(sev_active);
 
-static const struct dma_map_ops sev_dma_ops = {
-	.alloc                  = sev_alloc,
-	.free                   = sev_free,
-	.map_page               = swiotlb_map_page,
-	.unmap_page             = swiotlb_unmap_page,
-	.map_sg                 = swiotlb_map_sg_attrs,
-	.unmap_sg               = swiotlb_unmap_sg_attrs,
-	.sync_single_for_cpu    = swiotlb_sync_single_for_cpu,
-	.sync_single_for_device = swiotlb_sync_single_for_device,
-	.sync_sg_for_cpu        = swiotlb_sync_sg_for_cpu,
-	.sync_sg_for_device     = swiotlb_sync_sg_for_device,
-	.mapping_error          = swiotlb_dma_mapping_error,
-};
-
 /* Architecture __weak replacement functions */
 void __init mem_encrypt_init(void)
 {
@@ -428,12 +362,11 @@ void __init mem_encrypt_init(void)
 	swiotlb_update_mem_attributes();
 
 	/*
-	 * With SEV, DMA operations cannot use encryption. New DMA ops
-	 * are required in order to mark the DMA areas as decrypted or
-	 * to use bounce buffers.
+	 * With SEV, DMA operations cannot use encryption, we need to use
+	 * SWIOTLB to bounce buffer DMA operation.
 	 */
 	if (sev_active())
-		dma_ops = &sev_dma_ops;
+		dma_ops = &swiotlb_dma_ops;
 
 	/*
 	 * With SEV, we need to unroll the rep string I/O instructions.
diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
index eac58e03f43c..7a5bafb76d77 100644
--- a/arch/x86/pci/sta2x11-fixup.c
+++ b/arch/x86/pci/sta2x11-fixup.c
@@ -207,11 +207,11 @@ bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
 }
 
 /**
- * phys_to_dma - Return the DMA AMBA address used for this STA2x11 device
+ * __phys_to_dma - Return the DMA AMBA address used for this STA2x11 device
  * @dev: device for a PCI device
  * @paddr: Physical address
  */
-dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
 	if (!dev->archdata.is_sta2x11)
 		return paddr;
@@ -223,7 +223,7 @@ dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
  * @dev: device for a PCI device
  * @daddr: STA2x11 AMBA DMA address
  */
-phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
+phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
 {
 	if (!dev->archdata.is_sta2x11)
 		return daddr;
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index bcdb1a3e4b1f..53ad6a47f513 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -3,18 +3,19 @@
 #define _LINUX_DMA_DIRECT_H 1
 
 #include <linux/dma-mapping.h>
+#include <linux/mem_encrypt.h>
 
 #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
 #include <asm/dma-direct.h>
 #else
-static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
 	dma_addr_t dev_addr = (dma_addr_t)paddr;
 
 	return dev_addr - ((dma_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
 }
 
-static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
+static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr)
 {
 	phys_addr_t paddr = (phys_addr_t)dev_addr;
 
@@ -30,6 +31,22 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
 }
 #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */
 
+/*
+ * If memory encryption is supported, phys_to_dma will set the memory encryption
+ * bit in the DMA address, and dma_to_phys will clear it.  The raw __phys_to_dma
+ * and __dma_to_phys versions should only be used on non-encrypted memory for
+ * special occasions like DMA coherent buffers.
+ */
+static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
+{
+	return __sme_set(__phys_to_dma(dev, paddr));
+}
+
+static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
+{
+	return __sme_clr(__dma_to_phys(dev, daddr));
+}
+
 #ifdef CONFIG_ARCH_HAS_DMA_MARK_CLEAN
 void dma_mark_clean(void *addr, size_t size);
 #else
diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index c9e8e21cb334..84f50b5982fc 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -9,6 +9,7 @@
 #include <linux/scatterlist.h>
 #include <linux/dma-contiguous.h>
 #include <linux/pfn.h>
+#include <linux/set_memory.h>
 
 #define DIRECT_MAPPING_ERROR		0
 
@@ -35,9 +36,13 @@ check_addr(struct device *dev, dma_addr_t dma_addr, size_t size,
 	return true;
 }
 
+/*
+ * Since we will be clearing the encryption bit, check the mask with it already
+ * cleared.
+ */
 static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
 {
-	return phys_to_dma(dev, phys) + size - 1 <= dev->coherent_dma_mask;
+	return __phys_to_dma(dev, phys) + size - 1 <= dev->coherent_dma_mask;
 }
 
 void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
@@ -46,6 +51,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	int page_order = get_order(size);
 	struct page *page = NULL;
+	void *ret;
 
 	/* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */
 	if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
@@ -78,10 +84,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 
 	if (!page)
 		return NULL;
-
-	*dma_handle = phys_to_dma(dev, page_to_phys(page));
-	memset(page_address(page), 0, size);
-	return page_address(page);
+	*dma_handle = __phys_to_dma(dev, page_to_phys(page));
+	ret = page_address(page);
+	set_memory_decrypted((unsigned long)ret, page_order);
+	memset(ret, 0, size);
+	return ret;
 }
 
 /*
@@ -92,9 +99,11 @@ void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
 		dma_addr_t dma_addr, unsigned long attrs)
 {
 	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned int page_order = get_order(size);
 
+	set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
 	if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count))
-		free_pages((unsigned long)cpu_addr, get_order(size));
+		free_pages((unsigned long)cpu_addr, page_order);
 }
 
 static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index c43ec2271469..ca8eeaead925 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -158,13 +158,6 @@ unsigned long swiotlb_size_or_default(void)
 
 void __weak swiotlb_set_mem_attributes(void *vaddr, unsigned long size) { }
 
-/* For swiotlb, clear memory encryption mask from dma addresses */
-static dma_addr_t swiotlb_phys_to_dma(struct device *hwdev,
-				      phys_addr_t address)
-{
-	return __sme_clr(phys_to_dma(hwdev, address));
-}
-
 /* Note that this doesn't work with highmem page */
 static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
 				      volatile void *address)
@@ -622,7 +615,7 @@ map_single(struct device *hwdev, phys_addr_t phys, size_t size,
 		return SWIOTLB_MAP_ERROR;
 	}
 
-	start_dma_addr = swiotlb_phys_to_dma(hwdev, io_tlb_start);
+	start_dma_addr = __phys_to_dma(hwdev, io_tlb_start);
 	return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size,
 				      dir, attrs);
 }
@@ -726,12 +719,12 @@ swiotlb_alloc_buffer(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		goto out_warn;
 
 	phys_addr = swiotlb_tbl_map_single(dev,
-			swiotlb_phys_to_dma(dev, io_tlb_start),
+			__phys_to_dma(dev, io_tlb_start),
 			0, size, DMA_FROM_DEVICE, 0);
 	if (phys_addr == SWIOTLB_MAP_ERROR)
 		goto out_warn;
 
-	*dma_handle = swiotlb_phys_to_dma(dev, phys_addr);
+	*dma_handle = __phys_to_dma(dev, phys_addr);
 	if (dma_coherent_ok(dev, *dma_handle, size))
 		goto out_unmap;
 
@@ -867,10 +860,10 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
 	map = map_single(dev, phys, size, dir, attrs);
 	if (map == SWIOTLB_MAP_ERROR) {
 		swiotlb_full(dev, size, dir, 1);
-		return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer);
+		return __phys_to_dma(dev, io_tlb_overflow_buffer);
 	}
 
-	dev_addr = swiotlb_phys_to_dma(dev, map);
+	dev_addr = __phys_to_dma(dev, map);
 
 	/* Ensure that the address returned is DMA'ble */
 	if (dma_capable(dev, dev_addr, size))
@@ -879,7 +872,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
 	attrs |= DMA_ATTR_SKIP_CPU_SYNC;
 	swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
 
-	return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer);
+	return __phys_to_dma(dev, io_tlb_overflow_buffer);
 }
 
 /*
@@ -1009,7 +1002,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
 				sg_dma_len(sgl) = 0;
 				return 0;
 			}
-			sg->dma_address = swiotlb_phys_to_dma(hwdev, map);
+			sg->dma_address = __phys_to_dma(hwdev, map);
 		} else
 			sg->dma_address = dev_addr;
 		sg_dma_len(sg) = sg->length;
@@ -1073,7 +1066,7 @@ swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
 int
 swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
 {
-	return (dma_addr == swiotlb_phys_to_dma(hwdev, io_tlb_overflow_buffer));
+	return (dma_addr == __phys_to_dma(hwdev, io_tlb_overflow_buffer));
 }
 
 /*
@@ -1085,7 +1078,7 @@ swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
 int
 swiotlb_dma_supported(struct device *hwdev, u64 mask)
 {
-	return swiotlb_phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
+	return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
 }
 
 #ifdef CONFIG_DMA_DIRECT_OPS
-- 
2.14.2

[PATCH 12/13] swiotlb: remove swiotlb_set_mem_attributes

[Christoph Hellwig]

Now that set_memory_decrypted is always available we can just call it
directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/include/asm/mem_encrypt.h |  2 --
 arch/x86/mm/mem_encrypt.c          |  9 ---------
 lib/swiotlb.c                      | 12 ++++++------
 3 files changed, 6 insertions(+), 17 deletions(-)

diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 22c5f3e6f820..9da0b63c8fc7 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -48,8 +48,6 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size);
 /* Architecture __weak replacement functions */
 void __init mem_encrypt_init(void);
 
-void swiotlb_set_mem_attributes(void *vaddr, unsigned long size);
-
 bool sme_active(void);
 bool sev_active(void);
 
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 8bfc735bbdd7..65f45e0ef496 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -379,15 +379,6 @@ void __init mem_encrypt_init(void)
 			     : "Secure Memory Encryption (SME)");
 }
 
-void swiotlb_set_mem_attributes(void *vaddr, unsigned long size)
-{
-	WARN(PAGE_ALIGN(size) != size,
-	     "size is not page-aligned (%#lx)\n", size);
-
-	/* Make the SWIOTLB buffer area decrypted */
-	set_memory_decrypted((unsigned long)vaddr, size >> PAGE_SHIFT);
-}
-
 struct sme_populate_pgd_data {
 	void	*pgtable_area;
 	pgd_t	*pgd;
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index ca8eeaead925..8b06b4485e65 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -31,6 +31,7 @@
 #include <linux/gfp.h>
 #include <linux/scatterlist.h>
 #include <linux/mem_encrypt.h>
+#include <linux/set_memory.h>
 
 #include <asm/io.h>
 #include <asm/dma.h>
@@ -156,8 +157,6 @@ unsigned long swiotlb_size_or_default(void)
 	return size ? size : (IO_TLB_DEFAULT_SIZE);
 }
 
-void __weak swiotlb_set_mem_attributes(void *vaddr, unsigned long size) { }
-
 /* Note that this doesn't work with highmem page */
 static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
 				      volatile void *address)
@@ -202,12 +201,12 @@ void __init swiotlb_update_mem_attributes(void)
 
 	vaddr = phys_to_virt(io_tlb_start);
 	bytes = PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT);
-	swiotlb_set_mem_attributes(vaddr, bytes);
+	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
 	memset(vaddr, 0, bytes);
 
 	vaddr = phys_to_virt(io_tlb_overflow_buffer);
 	bytes = PAGE_ALIGN(io_tlb_overflow);
-	swiotlb_set_mem_attributes(vaddr, bytes);
+	set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT);
 	memset(vaddr, 0, bytes);
 }
 
@@ -348,7 +347,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 	io_tlb_start = virt_to_phys(tlb);
 	io_tlb_end = io_tlb_start + bytes;
 
-	swiotlb_set_mem_attributes(tlb, bytes);
+	set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT);
 	memset(tlb, 0, bytes);
 
 	/*
@@ -359,7 +358,8 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 	if (!v_overflow_buffer)
 		goto cleanup2;
 
-	swiotlb_set_mem_attributes(v_overflow_buffer, io_tlb_overflow);
+	set_memory_decrypted((unsigned long)v_overflow_buffer,
+			io_tlb_overflow >> PAGE_SHIFT);
 	memset(v_overflow_buffer, 0, io_tlb_overflow);
 	io_tlb_overflow_buffer = virt_to_phys(v_overflow_buffer);
 
-- 
2.14.2

[PATCH 13/13] swiotlb: remove swiotlb_{alloc,free}_coherent

[Christoph Hellwig]

Unused now that everyone uses swiotlb_{alloc,free}.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/swiotlb.h |  8 --------
 lib/swiotlb.c           | 38 --------------------------------------
 2 files changed, 46 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 5b1f2a00491c..965be92c33b5 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -72,14 +72,6 @@ void *swiotlb_alloc(struct device *hwdev, size_t size, dma_addr_t *dma_handle,
 void swiotlb_free(struct device *dev, size_t size, void *vaddr,
 		dma_addr_t dma_addr, unsigned long attrs);
 
-extern void
-*swiotlb_alloc_coherent(struct device *hwdev, size_t size,
-			dma_addr_t *dma_handle, gfp_t flags);
-
-extern void
-swiotlb_free_coherent(struct device *hwdev, size_t size,
-		      void *vaddr, dma_addr_t dma_handle);
-
 extern dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
 				   unsigned long offset, size_t size,
 				   enum dma_data_direction dir,
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 8b06b4485e65..15954b86f09e 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -157,13 +157,6 @@ unsigned long swiotlb_size_or_default(void)
 	return size ? size : (IO_TLB_DEFAULT_SIZE);
 }
 
-/* Note that this doesn't work with highmem page */
-static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
-				      volatile void *address)
-{
-	return phys_to_dma(hwdev, virt_to_phys(address));
-}
-
 static bool no_iotlb_memory;
 
 void swiotlb_print_info(void)
@@ -752,28 +745,6 @@ swiotlb_alloc_buffer(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	return NULL;
 }
 
-void *
-swiotlb_alloc_coherent(struct device *hwdev, size_t size,
-		       dma_addr_t *dma_handle, gfp_t flags)
-{
-	int order = get_order(size);
-	unsigned long attrs = (flags & __GFP_NOWARN) ? DMA_ATTR_NO_WARN : 0;
-	void *ret;
-
-	ret = (void *)__get_free_pages(flags, order);
-	if (ret) {
-		*dma_handle = swiotlb_virt_to_bus(hwdev, ret);
-		if (dma_coherent_ok(hwdev, *dma_handle, size)) {
-			memset(ret, 0, size);
-			return ret;
-		}
-		free_pages((unsigned long)ret, order);
-	}
-
-	return swiotlb_alloc_buffer(hwdev, size, dma_handle, attrs);
-}
-EXPORT_SYMBOL(swiotlb_alloc_coherent);
-
 static bool swiotlb_free_buffer(struct device *dev, size_t size,
 		dma_addr_t dma_addr)
 {
@@ -793,15 +764,6 @@ static bool swiotlb_free_buffer(struct device *dev, size_t size,
 	return true;
 }
 
-void
-swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
-		      dma_addr_t dev_addr)
-{
-	if (!swiotlb_free_buffer(hwdev, size, dev_addr))
-		free_pages((unsigned long)vaddr, get_order(size));
-}
-EXPORT_SYMBOL(swiotlb_free_coherent);
-
 static void
 swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir,
 	     int do_panic)
-- 
2.14.2

Re: [PATCH 04/13] x86: use generic swiotlb_ops

[Robin Murphy]

Hi Christoph,

On 05/03/18 17:46, Christoph Hellwig wrote:
> The generic swiotlb dma ops were based on the x86 ones and provide
> equivalent functionality, so use them.
> 
> Also fix the sta2x11 case.  For that SOC the dma map ops need an
> additional physical to dma address translations.  For swiotlb buffers
> that is done throught the phys_to_dma helper, but the sta2x11_dma_ops
> also added an additional translation on the return value from
> x86_swiotlb_alloc_coherent, which is only correct if that functions
> returns a direct allocation and not a swiotlb buffer.  With the
> generic swiotlb and dma-direct code phys_to_dma is not always used
> and the separate sta2x11_dma_ops can be replaced with a simple
> bit that marks if the additional physical to dma address translation
> is needed.

FWIW, last time I looked I got the impression that STA2x11 could just 
use dma_pfn_offset - the comments and a2p/p2a logic in sta2x11-fixup.c 
certainly imply that the underlying hardware situation is pretty much 
exactly that for which dma_pfn_offset exists.

Robin.

> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   arch/x86/include/asm/device.h  |  3 +++
>   arch/x86/include/asm/swiotlb.h |  8 -------
>   arch/x86/kernel/pci-swiotlb.c  | 47 +-----------------------------------------
>   arch/x86/pci/sta2x11-fixup.c   | 46 +++++------------------------------------
>   4 files changed, 9 insertions(+), 95 deletions(-)
> 
> diff --git a/arch/x86/include/asm/device.h b/arch/x86/include/asm/device.h
> index 5e12c63b47aa..812bd6c5d602 100644
> --- a/arch/x86/include/asm/device.h
> +++ b/arch/x86/include/asm/device.h
> @@ -6,6 +6,9 @@ struct dev_archdata {
>   #if defined(CONFIG_INTEL_IOMMU) || defined(CONFIG_AMD_IOMMU)
>   	void *iommu; /* hook for IOMMU specific extension */
>   #endif
> +#ifdef CONFIG_STA2X11
> +	bool is_sta2x11 : 1;
> +#endif
>   };
>   
>   #if defined(CONFIG_X86_DEV_DMA_OPS) && defined(CONFIG_PCI_DOMAINS)
> diff --git a/arch/x86/include/asm/swiotlb.h b/arch/x86/include/asm/swiotlb.h
> index 1c6a6cb230ff..ff6c92eff035 100644
> --- a/arch/x86/include/asm/swiotlb.h
> +++ b/arch/x86/include/asm/swiotlb.h
> @@ -27,12 +27,4 @@ static inline void pci_swiotlb_late_init(void)
>   {
>   }
>   #endif
> -
> -extern void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
> -					dma_addr_t *dma_handle, gfp_t flags,
> -					unsigned long attrs);
> -extern void x86_swiotlb_free_coherent(struct device *dev, size_t size,
> -					void *vaddr, dma_addr_t dma_addr,
> -					unsigned long attrs);
> -
>   #endif /* _ASM_X86_SWIOTLB_H */
> diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
> index bcb6a9bf64ad..661583662430 100644
> --- a/arch/x86/kernel/pci-swiotlb.c
> +++ b/arch/x86/kernel/pci-swiotlb.c
> @@ -17,51 +17,6 @@
>   
>   int swiotlb __read_mostly;
>   
> -void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
> -					dma_addr_t *dma_handle, gfp_t flags,
> -					unsigned long attrs)
> -{
> -	void *vaddr;
> -
> -	/*
> -	 * Don't print a warning when the first allocation attempt fails.
> -	 * swiotlb_alloc_coherent() will print a warning when the DMA
> -	 * memory allocation ultimately failed.
> -	 */
> -	flags |= __GFP_NOWARN;
> -
> -	vaddr = dma_direct_alloc(hwdev, size, dma_handle, flags, attrs);
> -	if (vaddr)
> -		return vaddr;
> -
> -	return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
> -}
> -
> -void x86_swiotlb_free_coherent(struct device *dev, size_t size,
> -				      void *vaddr, dma_addr_t dma_addr,
> -				      unsigned long attrs)
> -{
> -	if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
> -		swiotlb_free_coherent(dev, size, vaddr, dma_addr);
> -	else
> -		dma_direct_free(dev, size, vaddr, dma_addr, attrs);
> -}
> -
> -static const struct dma_map_ops x86_swiotlb_dma_ops = {
> -	.mapping_error = swiotlb_dma_mapping_error,
> -	.alloc = x86_swiotlb_alloc_coherent,
> -	.free = x86_swiotlb_free_coherent,
> -	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
> -	.sync_single_for_device = swiotlb_sync_single_for_device,
> -	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
> -	.sync_sg_for_device = swiotlb_sync_sg_for_device,
> -	.map_sg = swiotlb_map_sg_attrs,
> -	.unmap_sg = swiotlb_unmap_sg_attrs,
> -	.map_page = swiotlb_map_page,
> -	.unmap_page = swiotlb_unmap_page,
> -	.dma_supported = NULL,
> -};
> -
>   /*
>    * pci_swiotlb_detect_override - set swiotlb to 1 if necessary
>    *
> @@ -111,7 +66,7 @@ void __init pci_swiotlb_init(void)
>   {
>   	if (swiotlb) {
>   		swiotlb_init(0);
> -		dma_ops = &x86_swiotlb_dma_ops;
> +		dma_ops = &swiotlb_dma_ops;
>   	}
>   }
>   
> diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
> index 6c712fe11bdc..eac58e03f43c 100644
> --- a/arch/x86/pci/sta2x11-fixup.c
> +++ b/arch/x86/pci/sta2x11-fixup.c
> @@ -159,43 +159,6 @@ static dma_addr_t a2p(dma_addr_t a, struct pci_dev *pdev)
>   	return p;
>   }
>   
> -/**
> - * sta2x11_swiotlb_alloc_coherent - Allocate swiotlb bounce buffers
> - *     returns virtual address. This is the only "special" function here.
> - * @dev: PCI device
> - * @size: Size of the buffer
> - * @dma_handle: DMA address
> - * @flags: memory flags
> - */
> -static void *sta2x11_swiotlb_alloc_coherent(struct device *dev,
> -					    size_t size,
> -					    dma_addr_t *dma_handle,
> -					    gfp_t flags,
> -					    unsigned long attrs)
> -{
> -	void *vaddr;
> -
> -	vaddr = x86_swiotlb_alloc_coherent(dev, size, dma_handle, flags, attrs);
> -	*dma_handle = p2a(*dma_handle, to_pci_dev(dev));
> -	return vaddr;
> -}
> -
> -/* We have our own dma_ops: the same as swiotlb but from alloc (above) */
> -static const struct dma_map_ops sta2x11_dma_ops = {
> -	.alloc = sta2x11_swiotlb_alloc_coherent,
> -	.free = x86_swiotlb_free_coherent,
> -	.map_page = swiotlb_map_page,
> -	.unmap_page = swiotlb_unmap_page,
> -	.map_sg = swiotlb_map_sg_attrs,
> -	.unmap_sg = swiotlb_unmap_sg_attrs,
> -	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
> -	.sync_single_for_device = swiotlb_sync_single_for_device,
> -	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
> -	.sync_sg_for_device = swiotlb_sync_sg_for_device,
> -	.mapping_error = swiotlb_dma_mapping_error,
> -	.dma_supported = dma_direct_supported,
> -};
> -
>   /* At setup time, we use our own ops if the device is a ConneXt one */
>   static void sta2x11_setup_pdev(struct pci_dev *pdev)
>   {
> @@ -205,7 +168,8 @@ static void sta2x11_setup_pdev(struct pci_dev *pdev)
>   		return;
>   	pci_set_consistent_dma_mask(pdev, STA2X11_AMBA_SIZE - 1);
>   	pci_set_dma_mask(pdev, STA2X11_AMBA_SIZE - 1);
> -	pdev->dev.dma_ops = &sta2x11_dma_ops;
> +	pdev->dev.dma_ops = &swiotlb_dma_ops;
> +	pdev->dev.archdata.is_sta2x11 = true;
>   
>   	/* We must enable all devices as master, for audio DMA to work */
>   	pci_set_master(pdev);
> @@ -225,7 +189,7 @@ bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
>   {
>   	struct sta2x11_mapping *map;
>   
> -	if (dev->dma_ops != &sta2x11_dma_ops) {
> +	if (!dev->archdata.is_sta2x11) {
>   		if (!dev->dma_mask)
>   			return false;
>   		return addr + size - 1 <= *dev->dma_mask;
> @@ -249,7 +213,7 @@ bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
>    */
>   dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
>   {
> -	if (dev->dma_ops != &sta2x11_dma_ops)
> +	if (!dev->archdata.is_sta2x11)
>   		return paddr;
>   	return p2a(paddr, to_pci_dev(dev));
>   }
> @@ -261,7 +225,7 @@ dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
>    */
>   phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
>   {
> -	if (dev->dma_ops != &sta2x11_dma_ops)
> +	if (!dev->archdata.is_sta2x11)
>   		return daddr;
>   	return a2p(daddr, to_pci_dev(dev));
>   }
> 

Re: [PATCH 01/13] x86: remove X86_PPRO_FENCE

[Konrad Rzeszutek Wilk]

On Mon, Mar 05, 2018 at 09:46:43AM -0800, Christoph Hellwig wrote:
> There were only a few Pentium Pro multiprocessors systems where this
> errata applied. They are more than 20 years old now, and we've slowly
> dropped places where put the workarounds in and discouraged anyone
> from enabling the workaround.
> 
> Get rid of it for good.
> 

RIP.
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Thank you!

Re: [PATCH 02/13] x86: remove dma_alloc_coherent_mask

[Konrad Rzeszutek Wilk]

On Mon, Mar 05, 2018 at 09:46:44AM -0800, Christoph Hellwig wrote:
> These days all devices (including the ISA fallback device) have a coherent
> DMA mask set, so remove the workaround.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Thank you!

Re: [PATCH 04/13] x86: use generic swiotlb_ops

[Christoph Hellwig]

On Thu, Mar 08, 2018 at 04:03:12PM +0000, Robin Murphy wrote:
>> Also fix the sta2x11 case.  For that SOC the dma map ops need an
>> additional physical to dma address translations.  For swiotlb buffers
>> that is done throught the phys_to_dma helper, but the sta2x11_dma_ops
>> also added an additional translation on the return value from
>> x86_swiotlb_alloc_coherent, which is only correct if that functions
>> returns a direct allocation and not a swiotlb buffer.  With the
>> generic swiotlb and dma-direct code phys_to_dma is not always used
>> and the separate sta2x11_dma_ops can be replaced with a simple
>> bit that marks if the additional physical to dma address translation
>> is needed.
>
> FWIW, last time I looked I got the impression that STA2x11 could just use 
> dma_pfn_offset - the comments and a2p/p2a logic in sta2x11-fixup.c 
> certainly imply that the underlying hardware situation is pretty much 
> exactly that for which dma_pfn_offset exists.

That probably is the case.  But without access to the hardware I don't
feel like doing this deeper surgery.  And even without that this case
provides a great simplification.

Re: [PATCH 11/13] dma-direct: handle the memory encryption bit in common code

[Tom Lendacky]

On 3/5/2018 11:46 AM, Christoph Hellwig wrote:
> Give the basic phys_to_dma and dma_to_phys helpers a __-prefix and add
> the memory encryption mask to the non-prefixed versions.  Use the
> __-prefixed versions directly instead of clearing the mask again in
> various places.
> 
> With that in place the generic dma-direct routines can be used to
> allocate non-encrypted bounce buffers, and the x86 SEV case can use
> the generic swiotlb ops.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

So this patch results in my system failing to boot when SME is active.
I'm investigating further to see why.  I'll follow up with more details
as I find them.

Additionally, when running with SME (not SEV), this is forcing all DMA
coherent allocations to be decrypted, when that isn't required with SME
(as long as the device can perform 48-bit or greater DMA).  So it may
be worth looking at only doing the decrypted allocations for SEV.

Thanks,
Tom

> ---
>  arch/arm/include/asm/dma-direct.h                  |  4 +-
>  arch/mips/cavium-octeon/dma-octeon.c               | 10 +--
>  .../include/asm/mach-cavium-octeon/dma-coherence.h |  4 +-
>  .../include/asm/mach-loongson64/dma-coherence.h    | 10 +--
>  arch/mips/loongson64/common/dma-swiotlb.c          |  4 +-
>  arch/powerpc/include/asm/dma-direct.h              |  4 +-
>  arch/x86/Kconfig                                   |  2 +-
>  arch/x86/include/asm/dma-direct.h                  | 25 +-------
>  arch/x86/mm/mem_encrypt.c                          | 73 +---------------------
>  arch/x86/pci/sta2x11-fixup.c                       |  6 +-
>  include/linux/dma-direct.h                         | 21 ++++++-
>  lib/dma-direct.c                                   | 21 +++++--
>  lib/swiotlb.c                                      | 25 +++-----
>  13 files changed, 70 insertions(+), 139 deletions(-)
> 
> diff --git a/arch/arm/include/asm/dma-direct.h b/arch/arm/include/asm/dma-direct.h
> index 5b0a8a421894..b67e5fc1fe43 100644
> --- a/arch/arm/include/asm/dma-direct.h
> +++ b/arch/arm/include/asm/dma-direct.h
> @@ -2,13 +2,13 @@
>  #ifndef ASM_ARM_DMA_DIRECT_H
>  #define ASM_ARM_DMA_DIRECT_H 1
>  
> -static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
>  {
>  	unsigned int offset = paddr & ~PAGE_MASK;
>  	return pfn_to_dma(dev, __phys_to_pfn(paddr)) + offset;
>  }
>  
> -static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> +static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr)
>  {
>  	unsigned int offset = dev_addr & ~PAGE_MASK;
>  	return __pfn_to_phys(dma_to_pfn(dev, dev_addr)) + offset;
> diff --git a/arch/mips/cavium-octeon/dma-octeon.c b/arch/mips/cavium-octeon/dma-octeon.c
> index c7bb8a407041..7b335ab21697 100644
> --- a/arch/mips/cavium-octeon/dma-octeon.c
> +++ b/arch/mips/cavium-octeon/dma-octeon.c
> @@ -10,7 +10,7 @@
>   * IP32 changes by Ilya.
>   * Copyright (C) 2010 Cavium Networks, Inc.
>   */
> -#include <linux/dma-mapping.h>
> +#include <linux/dma-direct.h>
>  #include <linux/scatterlist.h>
>  #include <linux/bootmem.h>
>  #include <linux/export.h>
> @@ -182,7 +182,7 @@ struct octeon_dma_map_ops {
>  	phys_addr_t (*dma_to_phys)(struct device *dev, dma_addr_t daddr);
>  };
>  
> -dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
>  {
>  	struct octeon_dma_map_ops *ops = container_of(get_dma_ops(dev),
>  						      struct octeon_dma_map_ops,
> @@ -190,9 +190,9 @@ dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
>  
>  	return ops->phys_to_dma(dev, paddr);
>  }
> -EXPORT_SYMBOL(phys_to_dma);
> +EXPORT_SYMBOL(__phys_to_dma);
>  
> -phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> +phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
>  {
>  	struct octeon_dma_map_ops *ops = container_of(get_dma_ops(dev),
>  						      struct octeon_dma_map_ops,
> @@ -200,7 +200,7 @@ phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
>  
>  	return ops->dma_to_phys(dev, daddr);
>  }
> -EXPORT_SYMBOL(dma_to_phys);
> +EXPORT_SYMBOL(__dma_to_phys);
>  
>  static struct octeon_dma_map_ops octeon_linear_dma_map_ops = {
>  	.dma_map_ops = {
> diff --git a/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h b/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
> index 138edf6b5b48..6eb1ee548b11 100644
> --- a/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-cavium-octeon/dma-coherence.h
> @@ -69,8 +69,8 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
>  	return addr + size - 1 <= *dev->dma_mask;
>  }
>  
> -dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr);
> -phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr);
> +dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr);
> +phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr);
>  
>  struct dma_map_ops;
>  extern const struct dma_map_ops *octeon_pci_dma_map_ops;
> diff --git a/arch/mips/include/asm/mach-loongson64/dma-coherence.h b/arch/mips/include/asm/mach-loongson64/dma-coherence.h
> index b1b575f5c6c1..64fc44dec0a8 100644
> --- a/arch/mips/include/asm/mach-loongson64/dma-coherence.h
> +++ b/arch/mips/include/asm/mach-loongson64/dma-coherence.h
> @@ -25,13 +25,13 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
>  	return addr + size - 1 <= *dev->dma_mask;
>  }
>  
> -extern dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr);
> -extern phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr);
> +extern dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr);
> +extern phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr);
>  static inline dma_addr_t plat_map_dma_mem(struct device *dev, void *addr,
>  					  size_t size)
>  {
>  #ifdef CONFIG_CPU_LOONGSON3
> -	return phys_to_dma(dev, virt_to_phys(addr));
> +	return __phys_to_dma(dev, virt_to_phys(addr));
>  #else
>  	return virt_to_phys(addr) | 0x80000000;
>  #endif
> @@ -41,7 +41,7 @@ static inline dma_addr_t plat_map_dma_mem_page(struct device *dev,
>  					       struct page *page)
>  {
>  #ifdef CONFIG_CPU_LOONGSON3
> -	return phys_to_dma(dev, page_to_phys(page));
> +	return __phys_to_dma(dev, page_to_phys(page));
>  #else
>  	return page_to_phys(page) | 0x80000000;
>  #endif
> @@ -51,7 +51,7 @@ static inline unsigned long plat_dma_addr_to_phys(struct device *dev,
>  	dma_addr_t dma_addr)
>  {
>  #if defined(CONFIG_CPU_LOONGSON3) && defined(CONFIG_64BIT)
> -	return dma_to_phys(dev, dma_addr);
> +	return __dma_to_phys(dev, dma_addr);
>  #elif defined(CONFIG_CPU_LOONGSON2F) && defined(CONFIG_64BIT)
>  	return (dma_addr > 0x8fffffff) ? dma_addr : (dma_addr & 0x0fffffff);
>  #else
> diff --git a/arch/mips/loongson64/common/dma-swiotlb.c b/arch/mips/loongson64/common/dma-swiotlb.c
> index 7bbcf89475f3..6a739f8ae110 100644
> --- a/arch/mips/loongson64/common/dma-swiotlb.c
> +++ b/arch/mips/loongson64/common/dma-swiotlb.c
> @@ -63,7 +63,7 @@ static int loongson_dma_supported(struct device *dev, u64 mask)
>  	return swiotlb_dma_supported(dev, mask);
>  }
>  
> -dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
>  {
>  	long nid;
>  #ifdef CONFIG_PHYS48_TO_HT40
> @@ -75,7 +75,7 @@ dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
>  	return paddr;
>  }
>  
> -phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> +phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
>  {
>  	long nid;
>  #ifdef CONFIG_PHYS48_TO_HT40
> diff --git a/arch/powerpc/include/asm/dma-direct.h b/arch/powerpc/include/asm/dma-direct.h
> index a5b59c765426..7702875aabb7 100644
> --- a/arch/powerpc/include/asm/dma-direct.h
> +++ b/arch/powerpc/include/asm/dma-direct.h
> @@ -17,12 +17,12 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
>  	return addr + size - 1 <= *dev->dma_mask;
>  }
>  
> -static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
>  {
>  	return paddr + get_dma_offset(dev);
>  }
>  
> -static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> +static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
>  {
>  	return daddr - get_dma_offset(dev);
>  }
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 7272bb3768d7..6e25ca4c86ee 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -54,7 +54,6 @@ config X86
>  	select ARCH_HAS_FORTIFY_SOURCE
>  	select ARCH_HAS_GCOV_PROFILE_ALL
>  	select ARCH_HAS_KCOV			if X86_64
> -	select ARCH_HAS_PHYS_TO_DMA
>  	select ARCH_HAS_MEMBARRIER_SYNC_CORE
>  	select ARCH_HAS_PMEM_API		if X86_64
>  	select ARCH_HAS_REFCOUNT
> @@ -691,6 +690,7 @@ config X86_SUPPORTS_MEMORY_FAILURE
>  config STA2X11
>  	bool "STA2X11 Companion Chip Support"
>  	depends on X86_32_NON_STANDARD && PCI
> +	select ARCH_HAS_PHYS_TO_DMA
>  	select X86_DEV_DMA_OPS
>  	select X86_DMA_REMAP
>  	select SWIOTLB
> diff --git a/arch/x86/include/asm/dma-direct.h b/arch/x86/include/asm/dma-direct.h
> index 1295bc622ebe..1a19251eaac9 100644
> --- a/arch/x86/include/asm/dma-direct.h
> +++ b/arch/x86/include/asm/dma-direct.h
> @@ -2,29 +2,8 @@
>  #ifndef ASM_X86_DMA_DIRECT_H
>  #define ASM_X86_DMA_DIRECT_H 1
>  
> -#include <linux/mem_encrypt.h>
> -
> -#ifdef CONFIG_X86_DMA_REMAP /* Platform code defines bridge-specific code */
>  bool dma_capable(struct device *dev, dma_addr_t addr, size_t size);
> -dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr);
> -phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr);
> -#else
> -static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
> -{
> -	if (!dev->dma_mask)
> -		return 0;
> -
> -	return addr + size - 1 <= *dev->dma_mask;
> -}
> -
> -static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> -{
> -	return __sme_set(paddr);
> -}
> +dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr);
> +phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr);
>  
> -static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> -{
> -	return __sme_clr(daddr);
> -}
> -#endif /* CONFIG_X86_DMA_REMAP */
>  #endif /* ASM_X86_DMA_DIRECT_H */
> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index 66beedc8fe3d..8bfc735bbdd7 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -200,58 +200,6 @@ void __init sme_early_init(void)
>  		swiotlb_force = SWIOTLB_FORCE;
>  }
>  
> -static void *sev_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
> -		       gfp_t gfp, unsigned long attrs)
> -{
> -	unsigned int order;
> -	struct page *page;
> -	void *vaddr = NULL;
> -
> -	order = get_order(size);
> -	page = alloc_pages_node(dev_to_node(dev), gfp, order);
> -	if (page) {
> -		dma_addr_t addr;
> -
> -		/*
> -		 * Since we will be clearing the encryption bit, check the
> -		 * mask with it already cleared.
> -		 */
> -		addr = __sme_clr(phys_to_dma(dev, page_to_phys(page)));
> -		if ((addr + size) > dev->coherent_dma_mask) {
> -			__free_pages(page, get_order(size));
> -		} else {
> -			vaddr = page_address(page);
> -			*dma_handle = addr;
> -		}
> -	}
> -
> -	if (!vaddr)
> -		vaddr = swiotlb_alloc_coherent(dev, size, dma_handle, gfp);
> -
> -	if (!vaddr)
> -		return NULL;
> -
> -	/* Clear the SME encryption bit for DMA use if not swiotlb area */
> -	if (!is_swiotlb_buffer(dma_to_phys(dev, *dma_handle))) {
> -		set_memory_decrypted((unsigned long)vaddr, 1 << order);
> -		memset(vaddr, 0, PAGE_SIZE << order);
> -		*dma_handle = __sme_clr(*dma_handle);
> -	}
> -
> -	return vaddr;
> -}
> -
> -static void sev_free(struct device *dev, size_t size, void *vaddr,
> -		     dma_addr_t dma_handle, unsigned long attrs)
> -{
> -	/* Set the SME encryption bit for re-use if not swiotlb area */
> -	if (!is_swiotlb_buffer(dma_to_phys(dev, dma_handle)))
> -		set_memory_encrypted((unsigned long)vaddr,
> -				     1 << get_order(size));
> -
> -	swiotlb_free_coherent(dev, size, vaddr, dma_handle);
> -}
> -
>  static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
>  {
>  	pgprot_t old_prot, new_prot;
> @@ -404,20 +352,6 @@ bool sev_active(void)
>  }
>  EXPORT_SYMBOL(sev_active);
>  
> -static const struct dma_map_ops sev_dma_ops = {
> -	.alloc                  = sev_alloc,
> -	.free                   = sev_free,
> -	.map_page               = swiotlb_map_page,
> -	.unmap_page             = swiotlb_unmap_page,
> -	.map_sg                 = swiotlb_map_sg_attrs,
> -	.unmap_sg               = swiotlb_unmap_sg_attrs,
> -	.sync_single_for_cpu    = swiotlb_sync_single_for_cpu,
> -	.sync_single_for_device = swiotlb_sync_single_for_device,
> -	.sync_sg_for_cpu        = swiotlb_sync_sg_for_cpu,
> -	.sync_sg_for_device     = swiotlb_sync_sg_for_device,
> -	.mapping_error          = swiotlb_dma_mapping_error,
> -};
> -
>  /* Architecture __weak replacement functions */
>  void __init mem_encrypt_init(void)
>  {
> @@ -428,12 +362,11 @@ void __init mem_encrypt_init(void)
>  	swiotlb_update_mem_attributes();
>  
>  	/*
> -	 * With SEV, DMA operations cannot use encryption. New DMA ops
> -	 * are required in order to mark the DMA areas as decrypted or
> -	 * to use bounce buffers.
> +	 * With SEV, DMA operations cannot use encryption, we need to use
> +	 * SWIOTLB to bounce buffer DMA operation.
>  	 */
>  	if (sev_active())
> -		dma_ops = &sev_dma_ops;
> +		dma_ops = &swiotlb_dma_ops;
>  
>  	/*
>  	 * With SEV, we need to unroll the rep string I/O instructions.
> diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
> index eac58e03f43c..7a5bafb76d77 100644
> --- a/arch/x86/pci/sta2x11-fixup.c
> +++ b/arch/x86/pci/sta2x11-fixup.c
> @@ -207,11 +207,11 @@ bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
>  }
>  
>  /**
> - * phys_to_dma - Return the DMA AMBA address used for this STA2x11 device
> + * __phys_to_dma - Return the DMA AMBA address used for this STA2x11 device
>   * @dev: device for a PCI device
>   * @paddr: Physical address
>   */
> -dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
>  {
>  	if (!dev->archdata.is_sta2x11)
>  		return paddr;
> @@ -223,7 +223,7 @@ dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
>   * @dev: device for a PCI device
>   * @daddr: STA2x11 AMBA DMA address
>   */
> -phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> +phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
>  {
>  	if (!dev->archdata.is_sta2x11)
>  		return daddr;
> diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
> index bcdb1a3e4b1f..53ad6a47f513 100644
> --- a/include/linux/dma-direct.h
> +++ b/include/linux/dma-direct.h
> @@ -3,18 +3,19 @@
>  #define _LINUX_DMA_DIRECT_H 1
>  
>  #include <linux/dma-mapping.h>
> +#include <linux/mem_encrypt.h>
>  
>  #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
>  #include <asm/dma-direct.h>
>  #else
> -static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
>  {
>  	dma_addr_t dev_addr = (dma_addr_t)paddr;
>  
>  	return dev_addr - ((dma_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
>  }
>  
> -static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> +static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr)
>  {
>  	phys_addr_t paddr = (phys_addr_t)dev_addr;
>  
> @@ -30,6 +31,22 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
>  }
>  #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */
>  
> +/*
> + * If memory encryption is supported, phys_to_dma will set the memory encryption
> + * bit in the DMA address, and dma_to_phys will clear it.  The raw __phys_to_dma
> + * and __dma_to_phys versions should only be used on non-encrypted memory for
> + * special occasions like DMA coherent buffers.
> + */
> +static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> +{
> +	return __sme_set(__phys_to_dma(dev, paddr));
> +}
> +
> +static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> +{
> +	return __sme_clr(__dma_to_phys(dev, daddr));
> +}
> +
>  #ifdef CONFIG_ARCH_HAS_DMA_MARK_CLEAN
>  void dma_mark_clean(void *addr, size_t size);
>  #else
> diff --git a/lib/dma-direct.c b/lib/dma-direct.c
> index c9e8e21cb334..84f50b5982fc 100644
> --- a/lib/dma-direct.c
> +++ b/lib/dma-direct.c
> @@ -9,6 +9,7 @@
>  #include <linux/scatterlist.h>
>  #include <linux/dma-contiguous.h>
>  #include <linux/pfn.h>
> +#include <linux/set_memory.h>
>  
>  #define DIRECT_MAPPING_ERROR		0
>  
> @@ -35,9 +36,13 @@ check_addr(struct device *dev, dma_addr_t dma_addr, size_t size,
>  	return true;
>  }
>  
> +/*
> + * Since we will be clearing the encryption bit, check the mask with it already
> + * cleared.
> + */
>  static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
>  {
> -	return phys_to_dma(dev, phys) + size - 1 <= dev->coherent_dma_mask;
> +	return __phys_to_dma(dev, phys) + size - 1 <= dev->coherent_dma_mask;
>  }
>  
>  void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
> @@ -46,6 +51,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
>  	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
>  	int page_order = get_order(size);
>  	struct page *page = NULL;
> +	void *ret;
>  
>  	/* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */
>  	if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
> @@ -78,10 +84,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
>  
>  	if (!page)
>  		return NULL;
> -
> -	*dma_handle = phys_to_dma(dev, page_to_phys(page));
> -	memset(page_address(page), 0, size);
> -	return page_address(page);
> +	*dma_handle = __phys_to_dma(dev, page_to_phys(page));
> +	ret = page_address(page);
> +	set_memory_decrypted((unsigned long)ret, page_order);
> +	memset(ret, 0, size);
> +	return ret;
>  }
>  
>  /*
> @@ -92,9 +99,11 @@ void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
>  		dma_addr_t dma_addr, unsigned long attrs)
>  {
>  	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
> +	unsigned int page_order = get_order(size);
>  
> +	set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
>  	if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count))
> -		free_pages((unsigned long)cpu_addr, get_order(size));
> +		free_pages((unsigned long)cpu_addr, page_order);
>  }
>  
>  static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
> diff --git a/lib/swiotlb.c b/lib/swiotlb.c
> index c43ec2271469..ca8eeaead925 100644
> --- a/lib/swiotlb.c
> +++ b/lib/swiotlb.c
> @@ -158,13 +158,6 @@ unsigned long swiotlb_size_or_default(void)
>  
>  void __weak swiotlb_set_mem_attributes(void *vaddr, unsigned long size) { }
>  
> -/* For swiotlb, clear memory encryption mask from dma addresses */
> -static dma_addr_t swiotlb_phys_to_dma(struct device *hwdev,
> -				      phys_addr_t address)
> -{
> -	return __sme_clr(phys_to_dma(hwdev, address));
> -}
> -
>  /* Note that this doesn't work with highmem page */
>  static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
>  				      volatile void *address)
> @@ -622,7 +615,7 @@ map_single(struct device *hwdev, phys_addr_t phys, size_t size,
>  		return SWIOTLB_MAP_ERROR;
>  	}
>  
> -	start_dma_addr = swiotlb_phys_to_dma(hwdev, io_tlb_start);
> +	start_dma_addr = __phys_to_dma(hwdev, io_tlb_start);
>  	return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size,
>  				      dir, attrs);
>  }
> @@ -726,12 +719,12 @@ swiotlb_alloc_buffer(struct device *dev, size_t size, dma_addr_t *dma_handle,
>  		goto out_warn;
>  
>  	phys_addr = swiotlb_tbl_map_single(dev,
> -			swiotlb_phys_to_dma(dev, io_tlb_start),
> +			__phys_to_dma(dev, io_tlb_start),
>  			0, size, DMA_FROM_DEVICE, 0);
>  	if (phys_addr == SWIOTLB_MAP_ERROR)
>  		goto out_warn;
>  
> -	*dma_handle = swiotlb_phys_to_dma(dev, phys_addr);
> +	*dma_handle = __phys_to_dma(dev, phys_addr);
>  	if (dma_coherent_ok(dev, *dma_handle, size))
>  		goto out_unmap;
>  
> @@ -867,10 +860,10 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
>  	map = map_single(dev, phys, size, dir, attrs);
>  	if (map == SWIOTLB_MAP_ERROR) {
>  		swiotlb_full(dev, size, dir, 1);
> -		return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer);
> +		return __phys_to_dma(dev, io_tlb_overflow_buffer);
>  	}
>  
> -	dev_addr = swiotlb_phys_to_dma(dev, map);
> +	dev_addr = __phys_to_dma(dev, map);
>  
>  	/* Ensure that the address returned is DMA'ble */
>  	if (dma_capable(dev, dev_addr, size))
> @@ -879,7 +872,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
>  	attrs |= DMA_ATTR_SKIP_CPU_SYNC;
>  	swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
>  
> -	return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer);
> +	return __phys_to_dma(dev, io_tlb_overflow_buffer);
>  }
>  
>  /*
> @@ -1009,7 +1002,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
>  				sg_dma_len(sgl) = 0;
>  				return 0;
>  			}
> -			sg->dma_address = swiotlb_phys_to_dma(hwdev, map);
> +			sg->dma_address = __phys_to_dma(hwdev, map);
>  		} else
>  			sg->dma_address = dev_addr;
>  		sg_dma_len(sg) = sg->length;
> @@ -1073,7 +1066,7 @@ swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
>  int
>  swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
>  {
> -	return (dma_addr == swiotlb_phys_to_dma(hwdev, io_tlb_overflow_buffer));
> +	return (dma_addr == __phys_to_dma(hwdev, io_tlb_overflow_buffer));
>  }
>  
>  /*
> @@ -1085,7 +1078,7 @@ swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
>  int
>  swiotlb_dma_supported(struct device *hwdev, u64 mask)
>  {
> -	return swiotlb_phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
> +	return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
>  }
>  
>  #ifdef CONFIG_DMA_DIRECT_OPS
> 

Re: [PATCH 11/13] dma-direct: handle the memory encryption bit in common code

[Tom Lendacky]

On 3/12/2018 1:29 PM, Tom Lendacky wrote:
> On 3/5/2018 11:46 AM, Christoph Hellwig wrote:
>> Give the basic phys_to_dma and dma_to_phys helpers a __-prefix and add
>> the memory encryption mask to the non-prefixed versions.  Use the
>> __-prefixed versions directly instead of clearing the mask again in
>> various places.
>>
>> With that in place the generic dma-direct routines can be used to
>> allocate non-encrypted bounce buffers, and the x86 SEV case can use
>> the generic swiotlb ops.
>>
>> Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> So this patch results in my system failing to boot when SME is active.
> I'm investigating further to see why.  I'll follow up with more details
> as I find them.

Ok, I found one issue that allows this to work when the IOMMU isn't
enabled (see below).

But the bigger issue is when the IOMMU is enabled.  The IOMMU code uses
a common mapping routine to create the I/O page tables.  This routine
assumes that all memory being mapped is encrypted and therefore sets the
encryption bit in the I/O page tables.  With this patch, the call to
dma_alloc_direct() now returns un-encrypted memory which results in an
encryption mis-match.  I think keeping dma_alloc_direct() as it was prior
to this patch is the way to go.  It allows SME DMA allocations to remain
encrypted and avoids added complexity in the amd_iommu.c file.  This
would mean that SEV would still have special DMA operations (so that the
alloc/free can change the memory to un-encrypted).

What do you think?

> 
> Additionally, when running with SME (not SEV), this is forcing all DMA
> coherent allocations to be decrypted, when that isn't required with SME
> (as long as the device can perform 48-bit or greater DMA).  So it may
> be worth looking at only doing the decrypted allocations for SEV.
> 
> Thanks,
> Tom
> 
>> ---
>>  arch/arm/include/asm/dma-direct.h                  |  4 +-
>>  arch/mips/cavium-octeon/dma-octeon.c               | 10 +--
>>  .../include/asm/mach-cavium-octeon/dma-coherence.h |  4 +-
>>  .../include/asm/mach-loongson64/dma-coherence.h    | 10 +--
>>  arch/mips/loongson64/common/dma-swiotlb.c          |  4 +-
>>  arch/powerpc/include/asm/dma-direct.h              |  4 +-
>>  arch/x86/Kconfig                                   |  2 +-
>>  arch/x86/include/asm/dma-direct.h                  | 25 +-------
>>  arch/x86/mm/mem_encrypt.c                          | 73 +---------------------
>>  arch/x86/pci/sta2x11-fixup.c                       |  6 +-
>>  include/linux/dma-direct.h                         | 21 ++++++-
>>  lib/dma-direct.c                                   | 21 +++++--
>>  lib/swiotlb.c                                      | 25 +++-----
>>  13 files changed, 70 insertions(+), 139 deletions(-)
>>

< ... SNIP ... >

>> diff --git a/lib/dma-direct.c b/lib/dma-direct.c
>> index c9e8e21cb334..84f50b5982fc 100644
>> --- a/lib/dma-direct.c
>> +++ b/lib/dma-direct.c
>> @@ -9,6 +9,7 @@
>>  #include <linux/scatterlist.h>
>>  #include <linux/dma-contiguous.h>
>>  #include <linux/pfn.h>
>> +#include <linux/set_memory.h>
>>  
>>  #define DIRECT_MAPPING_ERROR		0
>>  
>> @@ -35,9 +36,13 @@ check_addr(struct device *dev, dma_addr_t dma_addr, size_t size,
>>  	return true;
>>  }
>>  
>> +/*
>> + * Since we will be clearing the encryption bit, check the mask with it already
>> + * cleared.
>> + */
>>  static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
>>  {
>> -	return phys_to_dma(dev, phys) + size - 1 <= dev->coherent_dma_mask;
>> +	return __phys_to_dma(dev, phys) + size - 1 <= dev->coherent_dma_mask;
>>  }
>>  
>>  void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
>> @@ -46,6 +51,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
>>  	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
>>  	int page_order = get_order(size);
>>  	struct page *page = NULL;
>> +	void *ret;
>>  
>>  	/* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */
>>  	if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
>> @@ -78,10 +84,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
>>  
>>  	if (!page)
>>  		return NULL;
>> -
>> -	*dma_handle = phys_to_dma(dev, page_to_phys(page));
>> -	memset(page_address(page), 0, size);
>> -	return page_address(page);
>> +	*dma_handle = __phys_to_dma(dev, page_to_phys(page));
>> +	ret = page_address(page);
>> +	set_memory_decrypted((unsigned long)ret, page_order);

The second parameter should be 1 << page_order to get the number of
pages.

Thanks,
Tom

>> +	memset(ret, 0, size);
>> +	return ret;
>>  }
>>  
>>  /*
>> @@ -92,9 +99,11 @@ void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
>>  		dma_addr_t dma_addr, unsigned long attrs)
>>  {
>>  	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
>> +	unsigned int page_order = get_order(size);
>>  
>> +	set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
>>  	if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count))
>> -		free_pages((unsigned long)cpu_addr, get_order(size));
>> +		free_pages((unsigned long)cpu_addr, page_order);
>>  }
>>  
>>  static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
>> diff --git a/lib/swiotlb.c b/lib/swiotlb.c
>> index c43ec2271469..ca8eeaead925 100644
>> --- a/lib/swiotlb.c
>> +++ b/lib/swiotlb.c
>> @@ -158,13 +158,6 @@ unsigned long swiotlb_size_or_default(void)
>>  
>>  void __weak swiotlb_set_mem_attributes(void *vaddr, unsigned long size) { }
>>  
>> -/* For swiotlb, clear memory encryption mask from dma addresses */
>> -static dma_addr_t swiotlb_phys_to_dma(struct device *hwdev,
>> -				      phys_addr_t address)
>> -{
>> -	return __sme_clr(phys_to_dma(hwdev, address));
>> -}
>> -
>>  /* Note that this doesn't work with highmem page */
>>  static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
>>  				      volatile void *address)
>> @@ -622,7 +615,7 @@ map_single(struct device *hwdev, phys_addr_t phys, size_t size,
>>  		return SWIOTLB_MAP_ERROR;
>>  	}
>>  
>> -	start_dma_addr = swiotlb_phys_to_dma(hwdev, io_tlb_start);
>> +	start_dma_addr = __phys_to_dma(hwdev, io_tlb_start);
>>  	return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size,
>>  				      dir, attrs);
>>  }
>> @@ -726,12 +719,12 @@ swiotlb_alloc_buffer(struct device *dev, size_t size, dma_addr_t *dma_handle,
>>  		goto out_warn;
>>  
>>  	phys_addr = swiotlb_tbl_map_single(dev,
>> -			swiotlb_phys_to_dma(dev, io_tlb_start),
>> +			__phys_to_dma(dev, io_tlb_start),
>>  			0, size, DMA_FROM_DEVICE, 0);
>>  	if (phys_addr == SWIOTLB_MAP_ERROR)
>>  		goto out_warn;
>>  
>> -	*dma_handle = swiotlb_phys_to_dma(dev, phys_addr);
>> +	*dma_handle = __phys_to_dma(dev, phys_addr);
>>  	if (dma_coherent_ok(dev, *dma_handle, size))
>>  		goto out_unmap;
>>  
>> @@ -867,10 +860,10 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
>>  	map = map_single(dev, phys, size, dir, attrs);
>>  	if (map == SWIOTLB_MAP_ERROR) {
>>  		swiotlb_full(dev, size, dir, 1);
>> -		return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer);
>> +		return __phys_to_dma(dev, io_tlb_overflow_buffer);
>>  	}
>>  
>> -	dev_addr = swiotlb_phys_to_dma(dev, map);
>> +	dev_addr = __phys_to_dma(dev, map);
>>  
>>  	/* Ensure that the address returned is DMA'ble */
>>  	if (dma_capable(dev, dev_addr, size))
>> @@ -879,7 +872,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
>>  	attrs |= DMA_ATTR_SKIP_CPU_SYNC;
>>  	swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
>>  
>> -	return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer);
>> +	return __phys_to_dma(dev, io_tlb_overflow_buffer);
>>  }
>>  
>>  /*
>> @@ -1009,7 +1002,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
>>  				sg_dma_len(sgl) = 0;
>>  				return 0;
>>  			}
>> -			sg->dma_address = swiotlb_phys_to_dma(hwdev, map);
>> +			sg->dma_address = __phys_to_dma(hwdev, map);
>>  		} else
>>  			sg->dma_address = dev_addr;
>>  		sg_dma_len(sg) = sg->length;
>> @@ -1073,7 +1066,7 @@ swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
>>  int
>>  swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
>>  {
>> -	return (dma_addr == swiotlb_phys_to_dma(hwdev, io_tlb_overflow_buffer));
>> +	return (dma_addr == __phys_to_dma(hwdev, io_tlb_overflow_buffer));
>>  }
>>  
>>  /*
>> @@ -1085,7 +1078,7 @@ swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
>>  int
>>  swiotlb_dma_supported(struct device *hwdev, u64 mask)
>>  {
>> -	return swiotlb_phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
>> +	return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
>>  }
>>  
>>  #ifdef CONFIG_DMA_DIRECT_OPS
>>

Re: [PATCH 11/13] dma-direct: handle the memory encryption bit in common code

[Christoph Hellwig]

On Mon, Mar 12, 2018 at 02:48:51PM -0500, Tom Lendacky wrote:
> Ok, I found one issue that allows this to work when the IOMMU isn't
> enabled (see below).

Thanks, folded!

> But the bigger issue is when the IOMMU is enabled.  The IOMMU code uses
> a common mapping routine to create the I/O page tables.  This routine
> assumes that all memory being mapped is encrypted and therefore sets the
> encryption bit in the I/O page tables.  With this patch, the call to
> dma_alloc_direct() now returns un-encrypted memory which results in an
> encryption mis-match.  I think keeping dma_alloc_direct() as it was prior
> to this patch is the way to go.  It allows SME DMA allocations to remain
> encrypted and avoids added complexity in the amd_iommu.c file.  This
> would mean that SEV would still have special DMA operations (so that the
> alloc/free can change the memory to un-encrypted).
> 
> What do you think?

In terms of logic you are right.  I still don't like keeping a just
slightly tweaked version of dma_alloc_direct around just for this, it
will be perpetually out of sync in terms of features and bug fixes.

What do you think about this version that does the decision at runtime:

	http://git.infradead.org/users/hch/misc.git/commitdiff/b89f24dc856595dc7610d672bf077195ab0dabf4

The full tree is available here for testing:

	git://git.infradead.org/users/hch/misc.git dma-direct-x86

Re: [PATCH 11/13] dma-direct: handle the memory encryption bit in common code

[Tom Lendacky]

On 03/13/2018 08:10 AM, Christoph Hellwig wrote:
> On Mon, Mar 12, 2018 at 02:48:51PM -0500, Tom Lendacky wrote:
>> Ok, I found one issue that allows this to work when the IOMMU isn't
>> enabled (see below).
> 
> Thanks, folded!
> 
>> But the bigger issue is when the IOMMU is enabled.  The IOMMU code uses
>> a common mapping routine to create the I/O page tables.  This routine
>> assumes that all memory being mapped is encrypted and therefore sets the
>> encryption bit in the I/O page tables.  With this patch, the call to
>> dma_alloc_direct() now returns un-encrypted memory which results in an
>> encryption mis-match.  I think keeping dma_alloc_direct() as it was prior
>> to this patch is the way to go.  It allows SME DMA allocations to remain
>> encrypted and avoids added complexity in the amd_iommu.c file.  This
>> would mean that SEV would still have special DMA operations (so that the
>> alloc/free can change the memory to un-encrypted).
>>
>> What do you think?
> 
> In terms of logic you are right.  I still don't like keeping a just
> slightly tweaked version of dma_alloc_direct around just for this, it
> will be perpetually out of sync in terms of features and bug fixes.
> 
> What do you think about this version that does the decision at runtime:
> 
> 	http://git.infradead.org/users/hch/misc.git/commitdiff/b89f24dc856595dc7610d672bf077195ab0dabf4
> 
> The full tree is available here for testing:
> 
> 	git://git.infradead.org/users/hch/misc.git dma-direct-x86
> 

Thanks for the pointer to the tree.  I did find one bug in the
allocation routine, that once fixed (see below), worked with SME
for IOMMU on and off and worked with an SEV guest.

I understand the comment about using sev_active() in the dma-direct
code, maybe we can up with something later to address that.

Thanks,
Tom

diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index 856e140..988a3d8 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -82,10 +82,12 @@ void *dma_direct_alloc(struct device *dev, size_t
size, dma_addr_t *dma_handle,

 	if (!page)
 		return NULL;
-	*dma_handle = __phys_to_dma(dev, page_to_phys(page));
+	*dma_handle = phys_to_dma(dev, page_to_phys(page));
 	ret = page_address(page);
-	if (sev_active())
+	if (sev_active()) {
+		*dma_handle = __phys_to_dma(dev, page_to_phys(page));
 		set_memory_decrypted((unsigned long)ret, 1 << page_order);
+	}
 	memset(ret, 0, size);
 	return ret;
 }

Re: [PATCH 11/13] dma-direct: handle the memory encryption bit in common code

[Christoph Hellwig]

Can you test and review the V3 of the series I just sent out?
We reall should get it into linux-next ASAP.

Re: [PATCH 11/13] dma-direct: handle the memory encryption bit in common code

[Tom Lendacky]

On 3/19/2018 5:39 AM, Christoph Hellwig wrote:
> Can you test and review the V3 of the series I just sent out?
> We reall should get it into linux-next ASAP.

Can do.  I'll get back to you on V3 thread with the results.

Thanks,
Tom

>