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author | Joerg Roedel <joerg.roedel@amd.com> | 2009-10-09 18:31:20 +0200 |
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committer | Joerg Roedel <joerg.roedel@amd.com> | 2009-10-09 18:37:46 +0200 |
commit | c5cca146aa03e1f60fb179df65f0dbaf17bc64ed (patch) | |
tree | 457cdf7d8b3a12f58328d06a2bfd8665b395b9ba /arch/x86/kernel/amd_iommu_init.c | |
parent | c7084b35eb1a4d3353a501508baf9d3d82822c93 (diff) | |
download | op-kernel-dev-c5cca146aa03e1f60fb179df65f0dbaf17bc64ed.zip op-kernel-dev-c5cca146aa03e1f60fb179df65f0dbaf17bc64ed.tar.gz |
x86/amd-iommu: Workaround for erratum 63
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.
Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Diffstat (limited to 'arch/x86/kernel/amd_iommu_init.c')
-rw-r--r-- | arch/x86/kernel/amd_iommu_init.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c index c1b17e9..498c8c7 100644 --- a/arch/x86/kernel/amd_iommu_init.c +++ b/arch/x86/kernel/amd_iommu_init.c @@ -509,6 +509,26 @@ 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) { @@ -537,6 +557,8 @@ 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); } |