[PATCH 0/9] suspend/resume support for amd iommu

[PATCH 0/9] suspend/resume support for amd iommu

[Joerg Roedel]

This patchset implements support for suspend/resume in the AMD IOMMU
driver for Linux. Please review.

diffstat:

 arch/x86/include/asm/amd_iommu.h       |    2 +
 arch/x86/include/asm/amd_iommu_types.h |    8 ++
 arch/x86/kernel/amd_iommu.c            |   37 +++++++-
 arch/x86/kernel/amd_iommu_init.c       |  144 ++++++++++++++++----------------
 4 files changed, 114 insertions(+), 77 deletions(-)

shortlog:

Joerg Roedel (9):
      amd-iommu: introduce for_each_iommu* macros
      amd-iommu: consolidate hardware initialization to one function
      amd-iommu: drop pointless iommu-loop in msi setup code
      amd-iommu: remove support for msi-x
      amd-iommu: add function to disable all iommus
      amd-iommu: add function to flush tlb for all domains
      amd-iommu: add function to flush tlb for all devices
      amd_iommu: un __init functions required for suspend/resume
      amd-iommu: implement suspend/resume

[PATCH 1/9] amd-iommu: introduce for_each_iommu* macros

[Joerg Roedel]

Impact: simplify iterating over all iommus in the system

This patch introduces the for_each_iommu and for_each_iommu_safe macros
to simplify the developers life when having to iterate over all AMD
IOMMUs in the system.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/include/asm/amd_iommu_types.h |    8 ++++++++
 arch/x86/kernel/amd_iommu.c            |    8 ++++----
 arch/x86/kernel/amd_iommu_init.c       |    8 ++++----
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index 95c8cd9..cf5ef17 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -196,6 +196,14 @@
 					      domain for an IOMMU */
 
 /*
+ * Make iterating over all IOMMUs easier
+ */
+#define for_each_iommu(iommu) \
+	list_for_each_entry((iommu), &amd_iommu_list, list)
+#define for_each_iommu_safe(iommu, next) \
+	list_for_each_entry_safe((iommu), (next), &amd_iommu_list, list)
+
+/*
  * This structure contains generic data for  IOMMU protection domains
  * independent of their use.
  */
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index a97db99..d9e9dc1 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -213,7 +213,7 @@ irqreturn_t amd_iommu_int_handler(int irq, void *data)
 {
 	struct amd_iommu *iommu;
 
-	list_for_each_entry(iommu, &amd_iommu_list, list)
+	for_each_iommu(iommu)
 		iommu_poll_events(iommu);
 
 	return IRQ_HANDLED;
@@ -440,7 +440,7 @@ static void iommu_flush_domain(u16 domid)
 	__iommu_build_inv_iommu_pages(&cmd, CMD_INV_IOMMU_ALL_PAGES_ADDRESS,
 				      domid, 1, 1);
 
-	list_for_each_entry(iommu, &amd_iommu_list, list) {
+	for_each_iommu(iommu) {
 		spin_lock_irqsave(&iommu->lock, flags);
 		__iommu_queue_command(iommu, &cmd);
 		__iommu_completion_wait(iommu);
@@ -1672,7 +1672,7 @@ int __init amd_iommu_init_dma_ops(void)
 	 * found in the system. Devices not assigned to any other
 	 * protection domain will be assigned to the default one.
 	 */
-	list_for_each_entry(iommu, &amd_iommu_list, list) {
+	for_each_iommu(iommu) {
 		iommu->default_dom = dma_ops_domain_alloc(iommu, order);
 		if (iommu->default_dom == NULL)
 			return -ENOMEM;
@@ -1710,7 +1710,7 @@ int __init amd_iommu_init_dma_ops(void)
 
 free_domains:
 
-	list_for_each_entry(iommu, &amd_iommu_list, list) {
+	for_each_iommu(iommu) {
 		if (iommu->default_dom)
 			dma_ops_domain_free(iommu->default_dom);
 	}
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 8c0be09..675a4b6 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -679,7 +679,7 @@ static void __init free_iommu_all(void)
 {
 	struct amd_iommu *iommu, *next;
 
-	list_for_each_entry_safe(iommu, next, &amd_iommu_list, list) {
+	for_each_iommu_safe(iommu, next) {
 		list_del(&iommu->list);
 		free_iommu_one(iommu);
 		kfree(iommu);
@@ -779,7 +779,7 @@ static int __init iommu_setup_msix(struct amd_iommu *iommu)
 	struct msix_entry entries[32]; /* only 32 supported by AMD IOMMU */
 	int nvec = 0, i;
 
-	list_for_each_entry(curr, &amd_iommu_list, list) {
+	for_each_iommu(curr) {
 		if (curr->dev == iommu->dev) {
 			entries[nvec].entry = curr->evt_msi_num;
 			entries[nvec].vector = 0;
@@ -818,7 +818,7 @@ static int __init iommu_setup_msi(struct amd_iommu *iommu)
 	int r;
 	struct amd_iommu *curr;
 
-	list_for_each_entry(curr, &amd_iommu_list, list) {
+	for_each_iommu(curr) {
 		if (curr->dev == iommu->dev)
 			curr->int_enabled = true;
 	}
@@ -971,7 +971,7 @@ static void __init enable_iommus(void)
 {
 	struct amd_iommu *iommu;
 
-	list_for_each_entry(iommu, &amd_iommu_list, list) {
+	for_each_iommu(iommu) {
 		iommu_set_exclusion_range(iommu);
 		iommu_init_msi(iommu);
 		iommu_enable_event_logging(iommu);
-- 
1.6.3.1

[PATCH 2/9] amd-iommu: consolidate hardware initialization to one function

[Joerg Roedel]

Impact: cleanup and consolidate hardware initialization

This patch restructures the AMD IOMMU initialization code to initialize
all hardware registers with one single function call.
This is helpful for suspend/resume support.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu_init.c |   50 ++++++++++++++++++++++++-------------
 1 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 675a4b6..74f4f1f 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -252,13 +252,6 @@ static void __init iommu_enable(struct amd_iommu *iommu)
 	iommu_feature_enable(iommu, CONTROL_IOMMU_EN);
 }
 
-/* Function to enable IOMMU event logging and event interrupts */
-static void __init iommu_enable_event_logging(struct amd_iommu *iommu)
-{
-	iommu_feature_enable(iommu, CONTROL_EVT_LOG_EN);
-	iommu_feature_enable(iommu, CONTROL_EVT_INT_EN);
-}
-
 /*
  * mapping and unmapping functions for the IOMMU MMIO space. Each AMD IOMMU in
  * the system has one.
@@ -413,25 +406,36 @@ static u8 * __init alloc_command_buffer(struct amd_iommu *iommu)
 {
 	u8 *cmd_buf = (u8 *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 			get_order(CMD_BUFFER_SIZE));
-	u64 entry;
 
 	if (cmd_buf == NULL)
 		return NULL;
 
 	iommu->cmd_buf_size = CMD_BUFFER_SIZE;
 
-	entry = (u64)virt_to_phys(cmd_buf);
+	return cmd_buf;
+}
+
+/*
+ * This function writes the command buffer address to the hardware and
+ * enables it.
+ */
+static void iommu_enable_command_buffer(struct amd_iommu *iommu)
+{
+	u64 entry;
+
+	BUG_ON(iommu->cmd_buf == NULL);
+
+	entry = (u64)virt_to_phys(iommu->cmd_buf);
 	entry |= MMIO_CMD_SIZE_512;
+
 	memcpy_toio(iommu->mmio_base + MMIO_CMD_BUF_OFFSET,
-			&entry, sizeof(entry));
+		    &entry, sizeof(entry));
 
 	/* set head and tail to zero manually */
 	writel(0x00, iommu->mmio_base + MMIO_CMD_HEAD_OFFSET);
 	writel(0x00, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
 
 	iommu_feature_enable(iommu, CONTROL_CMDBUF_EN);
-
-	return cmd_buf;
 }
 
 static void __init free_command_buffer(struct amd_iommu *iommu)
@@ -443,20 +447,27 @@ static void __init free_command_buffer(struct amd_iommu *iommu)
 /* allocates the memory where the IOMMU will log its events to */
 static u8 * __init alloc_event_buffer(struct amd_iommu *iommu)
 {
-	u64 entry;
 	iommu->evt_buf = (u8 *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 						get_order(EVT_BUFFER_SIZE));
 
 	if (iommu->evt_buf == NULL)
 		return NULL;
 
+	return iommu->evt_buf;
+}
+
+static void iommu_enable_event_buffer(struct amd_iommu *iommu)
+{
+	u64 entry;
+
+	BUG_ON(iommu->evt_buf == NULL);
+
 	entry = (u64)virt_to_phys(iommu->evt_buf) | EVT_LEN_MASK;
+
 	memcpy_toio(iommu->mmio_base + MMIO_EVT_BUF_OFFSET,
 		    &entry, sizeof(entry));
 
-	iommu->evt_buf_size = EVT_BUFFER_SIZE;
-
-	return iommu->evt_buf;
+	iommu_feature_enable(iommu, CONTROL_EVT_LOG_EN);
 }
 
 static void __init free_event_buffer(struct amd_iommu *iommu)
@@ -710,7 +721,6 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
 	if (!iommu->mmio_base)
 		return -ENOMEM;
 
-	iommu_set_device_table(iommu);
 	iommu->cmd_buf = alloc_command_buffer(iommu);
 	if (!iommu->cmd_buf)
 		return -ENOMEM;
@@ -837,6 +847,8 @@ static int __init iommu_setup_msi(struct amd_iommu *iommu)
 		return 1;
 	}
 
+	iommu_feature_enable(iommu, CONTROL_EVT_INT_EN);
+
 	return 0;
 }
 
@@ -972,9 +984,11 @@ static void __init enable_iommus(void)
 	struct amd_iommu *iommu;
 
 	for_each_iommu(iommu) {
+		iommu_set_device_table(iommu);
+		iommu_enable_command_buffer(iommu);
+		iommu_enable_event_buffer(iommu);
 		iommu_set_exclusion_range(iommu);
 		iommu_init_msi(iommu);
-		iommu_enable_event_logging(iommu);
 		iommu_enable(iommu);
 	}
 }
-- 
1.6.3.1

[PATCH 3/9] amd-iommu: drop pointless iommu-loop in msi setup code

[Joerg Roedel]

Impact: cleanup

It is not necessary to loop again over all IOMMUs in this code. So drop
the loop.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu_init.c |    8 +-------
 1 files changed, 1 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 74f4f1f..cc99f60 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -826,13 +826,6 @@ out_free:
 static int __init iommu_setup_msi(struct amd_iommu *iommu)
 {
 	int r;
-	struct amd_iommu *curr;
-
-	for_each_iommu(curr) {
-		if (curr->dev == iommu->dev)
-			curr->int_enabled = true;
-	}
-
 
 	if (pci_enable_msi(iommu->dev))
 		return 1;
@@ -847,6 +840,7 @@ static int __init iommu_setup_msi(struct amd_iommu *iommu)
 		return 1;
 	}
 
+	iommu->int_enabled = true;
 	iommu_feature_enable(iommu, CONTROL_EVT_INT_EN);
 
 	return 0;
-- 
1.6.3.1

[PATCH 4/9] amd-iommu: remove support for msi-x

[Joerg Roedel]

Impact: drop support for msi-x in amd iommu code

Current hardware uses msi instead of msi-x so this code it not necessary
and can not be tested. The best thing is to drop this code.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu_init.c |   44 +-------------------------------------
 1 files changed, 1 insertions(+), 43 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index cc99f60..feee475 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -783,46 +783,6 @@ static int __init init_iommu_all(struct acpi_table_header *table)
  *
  ****************************************************************************/
 
-static int __init iommu_setup_msix(struct amd_iommu *iommu)
-{
-	struct amd_iommu *curr;
-	struct msix_entry entries[32]; /* only 32 supported by AMD IOMMU */
-	int nvec = 0, i;
-
-	for_each_iommu(curr) {
-		if (curr->dev == iommu->dev) {
-			entries[nvec].entry = curr->evt_msi_num;
-			entries[nvec].vector = 0;
-			curr->int_enabled = true;
-			nvec++;
-		}
-	}
-
-	if (pci_enable_msix(iommu->dev, entries, nvec)) {
-		pci_disable_msix(iommu->dev);
-		return 1;
-	}
-
-	for (i = 0; i < nvec; ++i) {
-		int r = request_irq(entries->vector, amd_iommu_int_handler,
-				    IRQF_SAMPLE_RANDOM,
-				    "AMD IOMMU",
-				    NULL);
-		if (r)
-			goto out_free;
-	}
-
-	return 0;
-
-out_free:
-	for (i -= 1; i >= 0; --i)
-		free_irq(entries->vector, NULL);
-
-	pci_disable_msix(iommu->dev);
-
-	return 1;
-}
-
 static int __init iommu_setup_msi(struct amd_iommu *iommu)
 {
 	int r;
@@ -851,9 +811,7 @@ static int __init iommu_init_msi(struct amd_iommu *iommu)
 	if (iommu->int_enabled)
 		return 0;
 
-	if (pci_find_capability(iommu->dev, PCI_CAP_ID_MSIX))
-		return iommu_setup_msix(iommu);
-	else if (pci_find_capability(iommu->dev, PCI_CAP_ID_MSI))
+	if (pci_find_capability(iommu->dev, PCI_CAP_ID_MSI))
 		return iommu_setup_msi(iommu);
 
 	return 1;
-- 
1.6.3.1

[PATCH 5/9] amd-iommu: add function to disable all iommus

[Joerg Roedel]

[ impact: add disable_iommus function needed for suspend/resume ]

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu_init.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index feee475..ed10c0f 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -252,6 +252,11 @@ static void __init iommu_enable(struct amd_iommu *iommu)
 	iommu_feature_enable(iommu, CONTROL_IOMMU_EN);
 }
 
+static void iommu_disable(struct amd_iommu *iommu)
+{
+	iommu_feature_disable(iommu, CONTROL_IOMMU_EN);
+}
+
 /*
  * mapping and unmapping functions for the IOMMU MMIO space. Each AMD IOMMU in
  * the system has one.
@@ -945,6 +950,14 @@ static void __init enable_iommus(void)
 	}
 }
 
+static void disable_iommus(void)
+{
+	struct amd_iommu *iommu;
+
+	for_each_iommu(iommu)
+		iommu_disable(iommu);
+}
+
 /*
  * Suspend/Resume support
  * disable suspend until real resume implemented
-- 
1.6.3.1

[PATCH 6/9] amd-iommu: add function to flush tlb for all domains

[Joerg Roedel]

[ impact: be able to flush io/tlb for all allocated domains ]

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/include/asm/amd_iommu.h |    1 +
 arch/x86/kernel/amd_iommu.c      |   11 +++++++++++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/amd_iommu.h b/arch/x86/include/asm/amd_iommu.h
index f712344..1750e1f 100644
--- a/arch/x86/include/asm/amd_iommu.h
+++ b/arch/x86/include/asm/amd_iommu.h
@@ -27,6 +27,7 @@ extern int amd_iommu_init(void);
 extern int amd_iommu_init_dma_ops(void);
 extern void amd_iommu_detect(void);
 extern irqreturn_t amd_iommu_int_handler(int irq, void *data);
+extern void amd_iommu_flush_all_domains(void);
 #else
 static inline int amd_iommu_init(void) { return -ENODEV; }
 static inline void amd_iommu_detect(void) { }
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index d9e9dc1..826ad07 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -449,6 +449,17 @@ static void iommu_flush_domain(u16 domid)
 	}
 }
 
+void amd_iommu_flush_all_domains(void)
+{
+	int i;
+
+	for (i = 1; i < MAX_DOMAIN_ID; ++i) {
+		if (!test_bit(i, amd_iommu_pd_alloc_bitmap))
+			continue;
+		iommu_flush_domain(i);
+	}
+}
+
 /****************************************************************************
  *
  * The functions below are used the create the page table mappings for
-- 
1.6.3.1

[PATCH 7/9] amd-iommu: add function to flush tlb for all devices

[Joerg Roedel]

[ impact: be able to flush cache for all devtable entries ]

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/include/asm/amd_iommu.h |    1 +
 arch/x86/kernel/amd_iommu.c      |   18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/amd_iommu.h b/arch/x86/include/asm/amd_iommu.h
index 1750e1f..262e028 100644
--- a/arch/x86/include/asm/amd_iommu.h
+++ b/arch/x86/include/asm/amd_iommu.h
@@ -28,6 +28,7 @@ extern int amd_iommu_init_dma_ops(void);
 extern void amd_iommu_detect(void);
 extern irqreturn_t amd_iommu_int_handler(int irq, void *data);
 extern void amd_iommu_flush_all_domains(void);
+extern void amd_iommu_flush_all_devices(void);
 #else
 static inline int amd_iommu_init(void) { return -ENODEV; }
 static inline void amd_iommu_detect(void) { }
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 826ad07..92b0e18 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -460,6 +460,24 @@ void amd_iommu_flush_all_domains(void)
 	}
 }
 
+void amd_iommu_flush_all_devices(void)
+{
+	struct amd_iommu *iommu;
+	int i;
+
+	for (i = 0; i <= amd_iommu_last_bdf; ++i) {
+		if (amd_iommu_pd_table[i] == NULL)
+			continue;
+
+		iommu = amd_iommu_rlookup_table[i];
+		if (!iommu)
+			continue;
+
+		iommu_queue_inv_dev_entry(iommu, i);
+		iommu_completion_wait(iommu);
+	}
+}
+
 /****************************************************************************
  *
  * The functions below are used the create the page table mappings for
-- 
1.6.3.1

[PATCH 8/9] amd_iommu: un __init functions required for suspend/resume

[Joerg Roedel]

[ impact: keep functions in kernel .text required in resume path ]

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu_init.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index ed10c0f..330896b 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -193,7 +193,7 @@ static inline unsigned long tbl_size(int entry_size)
  * This function set the exclusion range in the IOMMU. DMA accesses to the
  * exclusion range are passed through untranslated
  */
-static void __init iommu_set_exclusion_range(struct amd_iommu *iommu)
+static void iommu_set_exclusion_range(struct amd_iommu *iommu)
 {
 	u64 start = iommu->exclusion_start & PAGE_MASK;
 	u64 limit = (start + iommu->exclusion_length) & PAGE_MASK;
@@ -225,7 +225,7 @@ static void __init iommu_set_device_table(struct amd_iommu *iommu)
 }
 
 /* Generic functions to enable/disable certain features of the IOMMU. */
-static void __init iommu_feature_enable(struct amd_iommu *iommu, u8 bit)
+static void iommu_feature_enable(struct amd_iommu *iommu, u8 bit)
 {
 	u32 ctrl;
 
@@ -244,7 +244,7 @@ static void __init iommu_feature_disable(struct amd_iommu *iommu, u8 bit)
 }
 
 /* Function to enable the hardware */
-static void __init iommu_enable(struct amd_iommu *iommu)
+static void iommu_enable(struct amd_iommu *iommu)
 {
 	printk(KERN_INFO "AMD IOMMU: Enabling IOMMU at %s cap 0x%hx\n",
 	       dev_name(&iommu->dev->dev), iommu->cap_ptr);
@@ -811,7 +811,7 @@ static int __init iommu_setup_msi(struct amd_iommu *iommu)
 	return 0;
 }
 
-static int __init iommu_init_msi(struct amd_iommu *iommu)
+static int iommu_init_msi(struct amd_iommu *iommu)
 {
 	if (iommu->int_enabled)
 		return 0;
@@ -936,7 +936,7 @@ static void init_device_table(void)
  * This function finally enables all IOMMUs found in the system after
  * they have been initialized
  */
-static void __init enable_iommus(void)
+static void enable_iommus(void)
 {
 	struct amd_iommu *iommu;
 
-- 
1.6.3.1

[PATCH 9/9] amd-iommu: implement suspend/resume

[Joerg Roedel]

[ impact: put everything together and enable suspend/resume ]

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu_init.c |   21 ++++++++++++++++++++-
 1 files changed, 20 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 330896b..4ca8fbf 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -965,12 +965,31 @@ static void disable_iommus(void)
 
 static int amd_iommu_resume(struct sys_device *dev)
 {
+	/*
+	 * Disable IOMMUs before reprogramming the hardware registers.
+	 * IOMMU is still enabled from the resume kernel.
+	 */
+	disable_iommus();
+
+	/* re-load the hardware */
+	enable_iommus();
+
+	/*
+	 * we have to flush after the IOMMUs are enabled because a
+	 * disabled IOMMU will never execute the commands we send
+	 */
+	amd_iommu_flush_all_domains();
+	amd_iommu_flush_all_devices();
+
 	return 0;
 }
 
 static int amd_iommu_suspend(struct sys_device *dev, pm_message_t state)
 {
-	return -EINVAL;
+	/* disable IOMMUs to go out of the way for BIOS */
+	disable_iommus();
+
+	return 0;
 }
 
 static struct sysdev_class amd_iommu_sysdev_class = {
-- 
1.6.3.1