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authorJoerg Roedel <joerg.roedel@amd.com>2009-11-06 11:50:26 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2009-11-09 16:52:48 -0800
commit2f72dc5da58baa3012cb04ea2309ba0f7ef8f574 (patch)
tree82db500300f5c408ec17328b93b1c741a56ed09d
parent7c536f4b06b335490228376e236f1897acfc6924 (diff)
x86/amd-iommu: Workaround for erratum 63
commit c5cca146aa03e1f60fb179df65f0dbaf17bc64ed upstream. There is an erratum for IOMMU hardware which documents undefined behavior when forwarding SMI requests from peripherals and the DTE of that peripheral has a sysmgt value of 01b. This problem caused weird IO_PAGE_FAULTS in my case. This patch implements the suggested workaround for that erratum into the AMD IOMMU driver. The erratum is documented with number 63. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/x86/kernel/amd_iommu_init.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c
index 3b06a9cc671d..7d58f328bffd 100644
--- a/arch/x86/kernel/amd_iommu_init.c
+++ b/arch/x86/kernel/amd_iommu_init.c
@@ -430,6 +430,27 @@ static void set_dev_entry_bit(u16 devid, u8 bit)
amd_iommu_dev_table[devid].data[i] |= (1 << _bit);
}
+static int get_dev_entry_bit(u16 devid, u8 bit)
+{
+ int i = (bit >> 5) & 0x07;
+ int _bit = bit & 0x1f;
+
+ return (amd_iommu_dev_table[devid].data[i] & (1 << _bit)) >> _bit;
+}
+
+
+void amd_iommu_apply_erratum_63(u16 devid)
+{
+ int sysmgt;
+
+ sysmgt = get_dev_entry_bit(devid, DEV_ENTRY_SYSMGT1) |
+ (get_dev_entry_bit(devid, DEV_ENTRY_SYSMGT2) << 1);
+
+ if (sysmgt == 0x01)
+ set_dev_entry_bit(devid, DEV_ENTRY_IW);
+}
+
+
/* Writes the specific IOMMU for a device into the rlookup table */
static void __init set_iommu_for_device(struct amd_iommu *iommu, u16 devid)
{
@@ -458,6 +479,8 @@ static void __init set_dev_entry_from_acpi(struct amd_iommu *iommu,
if (flags & ACPI_DEVFLAG_LINT1)
set_dev_entry_bit(devid, DEV_ENTRY_LINT1_PASS);
+ amd_iommu_apply_erratum_63(devid);
+
set_iommu_for_device(iommu, devid);
}