[GIT PULL][PATCH 0/12] IOMMU fixes for 2.6.34-rc3

[GIT PULL][PATCH 0/12] IOMMU fixes for 2.6.34-rc3

[Joerg Roedel]

Hi Ingo,

The following changes since commit 2eaa9cfdf33b8d7fb7aff27792192e0019ae8fc6:
  Linus Torvalds (1):
        Linux 2.6.34-rc3

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu.git iommu/fixes

Chris Wright (5):
      x86/amd-iommu: Pt mode fix for domain_destroy
      x86/amd-iommu: enable iommu before attaching devices
      x86/amd-iommu: warn when issuing command to uninitialized cmd buffer
      Revert "x86: disable IOMMUs on kernel crash"
      x86/amd-iommu: use for_each_pci_dev

Dan Carpenter (1):
      dma-debug: Cleanup for copy-loop in filter_write()

Joerg Roedel (6):
      x86/amd-iommu: Protect IOMMU-API map/unmap path
      x86/amd-iommu: Report errors in acpi parsing functions upstream
      x86/amd-iommu: Use helper function to destroy domain
      x86/amd-iommu: Remove obsolete parameter documentation
      Merge branch 'amd-iommu/fixes' into iommu/fixes
      x86/gart: Disable GART explicitly before initialization

Julia Lawall (1):
      x86/amd-iommu: Remove double NULL check in check_device

 Documentation/kernel-parameters.txt    |    5 ---
 arch/x86/include/asm/amd_iommu_types.h |    3 ++
 arch/x86/kernel/amd_iommu.c            |   20 +++++++++----
 arch/x86/kernel/amd_iommu_init.c       |   48 ++++++++++++++++++++++----------
 arch/x86/kernel/aperture_64.c          |   15 +++++++++-
 arch/x86/kernel/crash.c                |    6 ----
 arch/x86/kernel/pci-gart_64.c          |    3 ++
 lib/dma-debug.c                        |    2 +-
 8 files changed, 68 insertions(+), 34 deletions(-)

This pull request includes fixes that did not made it upstream during the merge
window, fixes for recently discovered problems with kdump and amd-iommu
enabled and a small documentation update. Please pull.

Thanks,

	Joerg

[PATCH 01/12] x86/amd-iommu: Remove double NULL check in check_device

[Joerg Roedel]

From: Julia Lawall <julia@diku.dk>

dev was tested just above, so drop the second test.

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index adb0ba0..2c4a501 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -118,7 +118,7 @@ static bool check_device(struct device *dev)
 		return false;
 
 	/* No device or no PCI device */
-	if (!dev || dev->bus != &pci_bus_type)
+	if (dev->bus != &pci_bus_type)
 		return false;
 
 	devid = get_device_id(dev);
-- 
1.7.0.4

[PATCH 02/12] x86/amd-iommu: Protect IOMMU-API map/unmap path

[Joerg Roedel]

This patch introduces a mutex to lock page table updates in
the IOMMU-API path. We can't use the spin_lock here because
this patch might sleep.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/include/asm/amd_iommu_types.h |    2 ++
 arch/x86/kernel/amd_iommu.c            |    9 +++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index ba19ad4..5e46e78 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -21,6 +21,7 @@
 #define _ASM_X86_AMD_IOMMU_TYPES_H
 
 #include <linux/types.h>
+#include <linux/mutex.h>
 #include <linux/list.h>
 #include <linux/spinlock.h>
 
@@ -237,6 +238,7 @@ struct protection_domain {
 	struct list_head list;  /* for list of all protection domains */
 	struct list_head dev_list; /* List of all devices in this domain */
 	spinlock_t lock;	/* mostly used to lock the page table*/
+	struct mutex api_lock;	/* protect page tables in the iommu-api path */
 	u16 id;			/* the domain id written to the device table */
 	int mode;		/* paging mode (0-6 levels) */
 	u64 *pt_root;		/* page table root pointer */
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 2c4a501..b97f2f1 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -2327,6 +2327,7 @@ static struct protection_domain *protection_domain_alloc(void)
 		return NULL;
 
 	spin_lock_init(&domain->lock);
+	mutex_init(&domain->api_lock);
 	domain->id = domain_id_alloc();
 	if (!domain->id)
 		goto out_err;
@@ -2456,6 +2457,8 @@ static int amd_iommu_map_range(struct iommu_domain *dom,
 	iova  &= PAGE_MASK;
 	paddr &= PAGE_MASK;
 
+	mutex_lock(&domain->api_lock);
+
 	for (i = 0; i < npages; ++i) {
 		ret = iommu_map_page(domain, iova, paddr, prot, PM_MAP_4k);
 		if (ret)
@@ -2465,6 +2468,8 @@ static int amd_iommu_map_range(struct iommu_domain *dom,
 		paddr += PAGE_SIZE;
 	}
 
+	mutex_unlock(&domain->api_lock);
+
 	return 0;
 }
 
@@ -2477,12 +2482,16 @@ static void amd_iommu_unmap_range(struct iommu_domain *dom,
 
 	iova  &= PAGE_MASK;
 
+	mutex_lock(&domain->api_lock);
+
 	for (i = 0; i < npages; ++i) {
 		iommu_unmap_page(domain, iova, PM_MAP_4k);
 		iova  += PAGE_SIZE;
 	}
 
 	iommu_flush_tlb_pde(domain);
+
+	mutex_unlock(&domain->api_lock);
 }
 
 static phys_addr_t amd_iommu_iova_to_phys(struct iommu_domain *dom,
-- 
1.7.0.4

[PATCH 03/12] x86/amd-iommu: Pt mode fix for domain_destroy

[Joerg Roedel]

From: Chris Wright <chrisw@sous-sol.org>

After a guest is shutdown, assigned devices are not properly
returned to the pt domain.  This can leave the device using
stale cached IOMMU data, and result in a non-functional
device after it's re-bound to the host driver.  For example,
I see this upon rebinding:

 AMD-Vi: Event logged [IO_PAGE_FAULT device=02:00.0 domain=0x0000 address=0x000000007e2a8000 flags=0x0050]
 AMD-Vi: Event logged [IO_PAGE_FAULT device=02:00.0 domain=0x0000 address=0x000000007e2a8040 flags=0x0050]
 AMD-Vi: Event logged [IO_PAGE_FAULT device=02:00.0 domain=0x0000 address=0x000000007e2a8080 flags=0x0050]
 AMD-Vi: Event logged [IO_PAGE_FAULT device=02:00.0 domain=0x0000 address=0x000000007e2a80c0 flags=0x0050]
 0000:02:00.0: eth2: Detected Hardware Unit Hang:
 ...

The amd_iommu_destroy_domain() function calls do_detach()
which doesn't reattach the pt domain to the device.
Use __detach_device() instead.

Cc: stable@kernel.org
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index b97f2f1..0c04254 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -2298,7 +2298,7 @@ static void cleanup_domain(struct protection_domain *domain)
 	list_for_each_entry_safe(dev_data, next, &domain->dev_list, list) {
 		struct device *dev = dev_data->dev;
 
-		do_detach(dev);
+		__detach_device(dev);
 		atomic_set(&dev_data->bind, 0);
 	}
 
-- 
1.7.0.4

[PATCH 04/12] x86/amd-iommu: Report errors in acpi parsing functions upstream

[Joerg Roedel]

Since acpi_table_parse ignores the return values of the
parsing function this patch introduces a workaround and
reports these errors upstream via a global variable.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu_init.c |   38 +++++++++++++++++++++++++++-----------
 1 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 9dc91b4..feaf471 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -138,9 +138,9 @@ int amd_iommus_present;
 bool amd_iommu_np_cache __read_mostly;
 
 /*
- * Set to true if ACPI table parsing and hardware intialization went properly
+ * The ACPI table parsing functions set this variable on an error
  */
-static bool amd_iommu_initialized;
+static int __initdata amd_iommu_init_err;
 
 /*
  * List of protection domains - used during resume
@@ -391,9 +391,11 @@ static int __init find_last_devid_acpi(struct acpi_table_header *table)
 	 */
 	for (i = 0; i < table->length; ++i)
 		checksum += p[i];
-	if (checksum != 0)
+	if (checksum != 0) {
 		/* ACPI table corrupt */
-		return -ENODEV;
+		amd_iommu_init_err = -ENODEV;
+		return 0;
+	}
 
 	p += IVRS_HEADER_LENGTH;
 
@@ -920,11 +922,16 @@ static int __init init_iommu_all(struct acpi_table_header *table)
 				    h->mmio_phys);
 
 			iommu = kzalloc(sizeof(struct amd_iommu), GFP_KERNEL);
-			if (iommu == NULL)
-				return -ENOMEM;
+			if (iommu == NULL) {
+				amd_iommu_init_err = -ENOMEM;
+				return 0;
+			}
+
 			ret = init_iommu_one(iommu, h);
-			if (ret)
-				return ret;
+			if (ret) {
+				amd_iommu_init_err = ret;
+				return 0;
+			}
 			break;
 		default:
 			break;
@@ -934,8 +941,6 @@ static int __init init_iommu_all(struct acpi_table_header *table)
 	}
 	WARN_ON(p != end);
 
-	amd_iommu_initialized = true;
-
 	return 0;
 }
 
@@ -1211,6 +1216,10 @@ static int __init amd_iommu_init(void)
 	if (acpi_table_parse("IVRS", find_last_devid_acpi) != 0)
 		return -ENODEV;
 
+	ret = amd_iommu_init_err;
+	if (ret)
+		goto out;
+
 	dev_table_size     = tbl_size(DEV_TABLE_ENTRY_SIZE);
 	alias_table_size   = tbl_size(ALIAS_TABLE_ENTRY_SIZE);
 	rlookup_table_size = tbl_size(RLOOKUP_TABLE_ENTRY_SIZE);
@@ -1270,12 +1279,19 @@ static int __init amd_iommu_init(void)
 	if (acpi_table_parse("IVRS", init_iommu_all) != 0)
 		goto free;
 
-	if (!amd_iommu_initialized)
+	if (amd_iommu_init_err) {
+		ret = amd_iommu_init_err;
 		goto free;
+	}
 
 	if (acpi_table_parse("IVRS", init_memory_definitions) != 0)
 		goto free;
 
+	if (amd_iommu_init_err) {
+		ret = amd_iommu_init_err;
+		goto free;
+	}
+
 	ret = sysdev_class_register(&amd_iommu_sysdev_class);
 	if (ret)
 		goto free;
-- 
1.7.0.4

[PATCH 05/12] x86/amd-iommu: Use helper function to destroy domain

[Joerg Roedel]

In the amd_iommu_domain_destroy the protection_domain_free
function is partly reimplemented. The 'partly' is the bug
here because the domain is not deleted from the domain list.
This results in use-after-free errors and data-corruption.
Fix it by just using protection_domain_free instead.

Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 0c04254..b06f29e 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -2380,9 +2380,7 @@ static void amd_iommu_domain_destroy(struct iommu_domain *dom)
 
 	free_pagetable(domain);
 
-	domain_id_free(domain->id);
-
-	kfree(domain);
+	protection_domain_free(domain);
 
 	dom->priv = NULL;
 }
-- 
1.7.0.4

[PATCH 06/12] x86/amd-iommu: enable iommu before attaching devices

[Joerg Roedel]

From: Chris Wright <chrisw@sous-sol.org>

Hit another kdump problem as reported by Neil Horman.  When initializaing
the IOMMU, we attach devices to their domains before the IOMMU is
fully (re)initialized.  Attaching a device will issue some important
invalidations.  In the context of the newly kexec'd kdump kernel, the
IOMMU may have stale cached data from the original kernel.  Because we
do the attach too early, the invalidation commands are placed in the new
command buffer before the IOMMU is updated w/ that buffer.  This leaves
the stale entries in the kdump context and can renders device unusable.
Simply enable the IOMMU before we do the attach.

Cc: stable@kernel.org
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu_init.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index feaf471..8975965 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -1304,6 +1304,8 @@ static int __init amd_iommu_init(void)
 	if (ret)
 		goto free;
 
+	enable_iommus();
+
 	if (iommu_pass_through)
 		ret = amd_iommu_init_passthrough();
 	else
@@ -1316,8 +1318,6 @@ static int __init amd_iommu_init(void)
 
 	amd_iommu_init_notifier();
 
-	enable_iommus();
-
 	if (iommu_pass_through)
 		goto out;
 
@@ -1331,6 +1331,7 @@ out:
 	return ret;
 
 free:
+	disable_iommus();
 
 	amd_iommu_uninit_devices();
 
-- 
1.7.0.4

[PATCH 07/12] x86/amd-iommu: warn when issuing command to uninitialized cmd buffer

[Joerg Roedel]

From: Chris Wright <chrisw@sous-sol.org>

To catch future potential issues we can add a warning whenever we issue
a command before the command buffer is fully initialized.

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/include/asm/amd_iommu_types.h |    1 +
 arch/x86/kernel/amd_iommu.c            |    1 +
 arch/x86/kernel/amd_iommu_init.c       |    5 +++--
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index 5e46e78..86a0ff0 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -141,6 +141,7 @@
 
 /* constants to configure the command buffer */
 #define CMD_BUFFER_SIZE    8192
+#define CMD_BUFFER_UNINITIALIZED 1
 #define CMD_BUFFER_ENTRIES 512
 #define MMIO_CMD_SIZE_SHIFT 56
 #define MMIO_CMD_SIZE_512 (0x9ULL << MMIO_CMD_SIZE_SHIFT)
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index b06f29e..71dfc0a 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -392,6 +392,7 @@ static int __iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
 	u32 tail, head;
 	u8 *target;
 
+	WARN_ON(iommu->cmd_buf_size & CMD_BUFFER_UNINITIALIZED);
 	tail = readl(iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
 	target = iommu->cmd_buf + tail;
 	memcpy_toio(target, cmd, sizeof(*cmd));
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 8975965..5edf41c 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -438,7 +438,7 @@ static u8 * __init alloc_command_buffer(struct amd_iommu *iommu)
 	if (cmd_buf == NULL)
 		return NULL;
 
-	iommu->cmd_buf_size = CMD_BUFFER_SIZE;
+	iommu->cmd_buf_size = CMD_BUFFER_SIZE | CMD_BUFFER_UNINITIALIZED;
 
 	return cmd_buf;
 }
@@ -474,12 +474,13 @@ static void iommu_enable_command_buffer(struct amd_iommu *iommu)
 		    &entry, sizeof(entry));
 
 	amd_iommu_reset_cmd_buffer(iommu);
+	iommu->cmd_buf_size &= ~(CMD_BUFFER_UNINITIALIZED);
 }
 
 static void __init free_command_buffer(struct amd_iommu *iommu)
 {
 	free_pages((unsigned long)iommu->cmd_buf,
-		   get_order(iommu->cmd_buf_size));
+		   get_order(iommu->cmd_buf_size & ~(CMD_BUFFER_UNINITIALIZED)));
 }
 
 /* allocates the memory where the IOMMU will log its events to */
-- 
1.7.0.4

[PATCH 08/12] Revert "x86: disable IOMMUs on kernel crash"

[Joerg Roedel]

From: Chris Wright <chrisw@sous-sol.org>

This effectively reverts commit 61d047be99757fd9b0af900d7abce9a13a337488.

Disabling the IOMMU can potetially allow DMA transactions to
complete without being translated.  Leave it enabled, and allow
crash kernel to do the IOMMU reinitialization properly.

Cc: stable@kernel.org
Cc: Joerg Roedel <joerg.roedel@amd.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/crash.c |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index a4849c1..ebd4c51 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -27,7 +27,6 @@
 #include <asm/cpu.h>
 #include <asm/reboot.h>
 #include <asm/virtext.h>
-#include <asm/x86_init.h>
 
 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
 
@@ -103,10 +102,5 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
 #ifdef CONFIG_HPET_TIMER
 	hpet_disable();
 #endif
-
-#ifdef CONFIG_X86_64
-	x86_platform.iommu_shutdown();
-#endif
-
 	crash_save_cpu(regs, safe_smp_processor_id());
 }
-- 
1.7.0.4

[PATCH 09/12] x86/amd-iommu: use for_each_pci_dev

[Joerg Roedel]

From: Chris Wright <chrisw@sous-sol.org>

Replace open coded version with for_each_pci_dev

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 71dfc0a..4949568 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -2187,7 +2187,7 @@ static void prealloc_protection_domains(void)
 	struct dma_ops_domain *dma_dom;
 	u16 devid;
 
-	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
+	for_each_pci_dev(dev) {
 
 		/* Do we handle this device? */
 		if (!check_device(&dev->dev))
-- 
1.7.0.4

[PATCH 10/12] x86/amd-iommu: Remove obsolete parameter documentation

[Joerg Roedel]

Support for the share and fullflush parameters was removed.
Remove the documentation about them too.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 Documentation/kernel-parameters.txt |    5 -----
 1 files changed, 0 insertions(+), 5 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e7848a0..ccea846 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -323,11 +323,6 @@ and is between 256 and 4096 characters. It is defined in the file
 	amd_iommu=	[HW,X86-84]
 			Pass parameters to the AMD IOMMU driver in the system.
 			Possible values are:
-			isolate - enable device isolation (each device, as far
-			          as possible, will get its own protection
-			          domain) [default]
-			share - put every device behind one IOMMU into the
-				same protection domain
 			fullflush - enable flushing of IO/TLB entries when
 				    they are unmapped. Otherwise they are
 				    flushed before they will be reused, which
-- 
1.7.0.4

[PATCH 11/12] dma-debug: Cleanup for copy-loop in filter_write()

[Joerg Roedel]

From: Dan Carpenter <error27@gmail.com>

Earlier in this function we set the last byte of "buf" to NULL so we
always hit the break statement and "i" is never equal to NAME_MAX_LEN.
This patch doesn't change how the driver works but it silences a Smatch
warning and it makes it clearer that we don't write past the end of the
array.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 lib/dma-debug.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index ba8b670..01e6427 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -570,7 +570,7 @@ static ssize_t filter_write(struct file *file, const char __user *userbuf,
 	 * Now parse out the first token and use it as the name for the
 	 * driver to filter for.
 	 */
-	for (i = 0; i < NAME_MAX_LEN; ++i) {
+	for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 		current_driver_name[i] = buf[i];
 		if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 			break;
-- 
1.7.0.4

[PATCH 12/12] x86/gart: Disable GART explicitly before initialization

[Joerg Roedel]

If we boot into a crash-kernel the gart might still be
enabled and its caches might be dirty. This can result in
undefined behavior later. Fix it by explicitly disabling the
gart hardware before initialization and flushing the caches
after enablement.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/aperture_64.c |   15 ++++++++++++++-
 arch/x86/kernel/pci-gart_64.c |    3 +++
 2 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index 3704997..b5d8b0b 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -393,6 +393,7 @@ void __init gart_iommu_hole_init(void)
 	for (i = 0; i < ARRAY_SIZE(bus_dev_ranges); i++) {
 		int bus;
 		int dev_base, dev_limit;
+		u32 ctl;
 
 		bus = bus_dev_ranges[i].bus;
 		dev_base = bus_dev_ranges[i].dev_base;
@@ -406,7 +407,19 @@ void __init gart_iommu_hole_init(void)
 			gart_iommu_aperture = 1;
 			x86_init.iommu.iommu_init = gart_iommu_init;
 
-			aper_order = (read_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL) >> 1) & 7;
+			ctl = read_pci_config(bus, slot, 3,
+					      AMD64_GARTAPERTURECTL);
+
+			/*
+			 * Before we do anything else disable the GART. It may
+			 * still be enabled if we boot into a crash-kernel here.
+			 * Reconfiguring the GART while it is enabled could have
+			 * unknown side-effects.
+			 */
+			ctl &= ~GARTEN;
+			write_pci_config(bus, slot, 3, AMD64_GARTAPERTURECTL, ctl);
+
+			aper_order = (ctl >> 1) & 7;
 			aper_size = (32 * 1024 * 1024) << aper_order;
 			aper_base = read_pci_config(bus, slot, 3, AMD64_GARTAPERTUREBASE) & 0x7fff;
 			aper_base <<= 25;
diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index f3af115..0ae24d9 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -564,6 +564,9 @@ static void enable_gart_translations(void)
 
 		enable_gart_translation(dev, __pa(agp_gatt_table));
 	}
+
+	/* Flush the GART-TLB to remove stale entries */
+	k8_flush_garts();
 }
 
 /*
-- 
1.7.0.4

Re: [GIT PULL][PATCH 0/12] IOMMU fixes for 2.6.34-rc3

[Ingo Molnar]

* Joerg Roedel <joerg.roedel@amd.com> wrote:

> Hi Ingo,
> 
> The following changes since commit 2eaa9cfdf33b8d7fb7aff27792192e0019ae8fc6:
>   Linus Torvalds (1):
>         Linux 2.6.34-rc3
> 
> are available in the git repository at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu.git iommu/fixes
> 
> Chris Wright (5):
>       x86/amd-iommu: Pt mode fix for domain_destroy
>       x86/amd-iommu: enable iommu before attaching devices
>       x86/amd-iommu: warn when issuing command to uninitialized cmd buffer
>       Revert "x86: disable IOMMUs on kernel crash"
>       x86/amd-iommu: use for_each_pci_dev
> 
> Dan Carpenter (1):
>       dma-debug: Cleanup for copy-loop in filter_write()
> 
> Joerg Roedel (6):
>       x86/amd-iommu: Protect IOMMU-API map/unmap path
>       x86/amd-iommu: Report errors in acpi parsing functions upstream
>       x86/amd-iommu: Use helper function to destroy domain
>       x86/amd-iommu: Remove obsolete parameter documentation
>       Merge branch 'amd-iommu/fixes' into iommu/fixes
>       x86/gart: Disable GART explicitly before initialization
> 
> Julia Lawall (1):
>       x86/amd-iommu: Remove double NULL check in check_device
> 
>  Documentation/kernel-parameters.txt    |    5 ---
>  arch/x86/include/asm/amd_iommu_types.h |    3 ++
>  arch/x86/kernel/amd_iommu.c            |   20 +++++++++----
>  arch/x86/kernel/amd_iommu_init.c       |   48 ++++++++++++++++++++++----------
>  arch/x86/kernel/aperture_64.c          |   15 +++++++++-
>  arch/x86/kernel/crash.c                |    6 ----
>  arch/x86/kernel/pci-gart_64.c          |    3 ++
>  lib/dma-debug.c                        |    2 +-
>  8 files changed, 68 insertions(+), 34 deletions(-)
> 
> This pull request includes fixes that did not made it upstream during the merge
> window, fixes for recently discovered problems with kdump and amd-iommu
> enabled and a small documentation update. Please pull.

Pulled, thanks a lot Joerg!

	Ingo