linux-kernel - [PATCH 17/28] iommu/amd: Split device table initialization into irq and dma part

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Date:	Thu, 5 Jul 2012 14:36:37 +0200
From:	Joerg Roedel <joerg.roedel@....com>
To:	<iommu@...ts.linux-foundation.org>
CC:	<linux-kernel@...r.kernel.org>, Joerg Roedel <joerg.roedel@....com>
Subject: [PATCH 17/28] iommu/amd: Split device table initialization into irq and dma part

When the IOMMU is enabled very early (as with irq-remapping)
some devices are still in BIOS hand. When dma is blocked
early this can cause lots of IO_PAGE_FAULTs. So delay the
DMA initialization and do it right before the dma_ops are
initialized.

Signed-off-by: Joerg Roedel <joerg.roedel@....com>
---
 drivers/iommu/amd_iommu_init.c |   22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index e663f1d..453f80a 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1383,19 +1383,27 @@ static int __init init_memory_definitions(struct acpi_table_header *table)
  * Init the device table to not allow DMA access for devices and
  * suppress all page faults
  */
-static void init_device_table(void)
+static void init_device_table_dma(void)
 {
 	u32 devid;
 
 	for (devid = 0; devid <= amd_iommu_last_bdf; ++devid) {
 		set_dev_entry_bit(devid, DEV_ENTRY_VALID);
 		set_dev_entry_bit(devid, DEV_ENTRY_TRANSLATION);
-
-		if (amd_iommu_irq_remap)
-			set_dev_entry_bit(devid, DEV_ENTRY_IRQ_TBL_EN);
 	}
 }
 
+static void init_device_table(void)
+{
+	u32 devid;
+
+	if (!amd_iommu_irq_remap)
+		return;
+
+	for (devid = 0; devid <= amd_iommu_last_bdf; ++devid)
+		set_dev_entry_bit(devid, DEV_ENTRY_IRQ_TBL_EN);
+}
+
 static void iommu_init_flags(struct amd_iommu *iommu)
 {
 	iommu->acpi_flags & IVHD_FLAG_HT_TUN_EN_MASK ?
@@ -1783,8 +1791,14 @@ static bool detect_ivrs(void)
 
 static int amd_iommu_init_dma(void)
 {
+	struct amd_iommu *iommu;
 	int ret;
 
+	init_device_table_dma();
+
+	for_each_iommu(iommu)
+		iommu_flush_all_caches(iommu);
+
 	if (iommu_pass_through)
 		ret = amd_iommu_init_passthrough();
 	else
-- 
1.7.9.5


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