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IOMMU fixes for Linux v3.8-rc5

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One fix for the AMD IOMMU driver to work around broken BIOSes found in
 the field. Some BIOSes forget to enable a workaround for a hardware
 problem which might cause the IOMMU to stop working under high load
 conditions. The fix makes sure this workaround is enabled.
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Merge tag 'iommu-fixes-v3.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu

Pull IOMMU fix from Joerg Roedel:
 "One fix for the AMD IOMMU driver to work around broken BIOSes found in
  the field.  Some BIOSes forget to enable a workaround for a hardware
  problem which might cause the IOMMU to stop working under high load
  conditions.  The fix makes sure this workaround is enabled."

* tag 'iommu-fixes-v3.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  IOMMU, AMD Family15h Model10-1Fh erratum 746 Workaround
This commit is contained in:
Linus Torvalds 2013-01-28 11:52:56 -08:00
commit ae2c3d95fa
1 changed files with 34 additions and 0 deletions
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34
drivers/iommu/amd_iommu_init.c
View File

@ -974,6 +974,38 @@ static void __init free_iommu_all(void)
}
}
/*
* Family15h Model 10h-1fh erratum 746 (IOMMU Logging May Stall Translations)
* Workaround:
* BIOS should disable L2B micellaneous clock gating by setting
* L2_L2B_CK_GATE_CONTROL[CKGateL2BMiscDisable](D0F2xF4_x90[2]) = 1b
*/
static void __init amd_iommu_erratum_746_workaround(struct amd_iommu *iommu)
{
u32 value;
if ((boot_cpu_data.x86 != 0x15) ||
(boot_cpu_data.x86_model < 0x10) ||
(boot_cpu_data.x86_model > 0x1f))
return;
pci_write_config_dword(iommu->dev, 0xf0, 0x90);
pci_read_config_dword(iommu->dev, 0xf4, &value);
if (value & BIT(2))
return;
/* Select NB indirect register 0x90 and enable writing */
pci_write_config_dword(iommu->dev, 0xf0, 0x90 | (1 << 8));
pci_write_config_dword(iommu->dev, 0xf4, value | 0x4);
pr_info("AMD-Vi: Applying erratum 746 workaround for IOMMU at %s\n",
dev_name(&iommu->dev->dev));
/* Clear the enable writing bit */
pci_write_config_dword(iommu->dev, 0xf0, 0x90);
}
/*
* This function clues the initialization function for one IOMMU
* together and also allocates the command buffer and programs the
@ -1172,6 +1204,8 @@ static int iommu_init_pci(struct amd_iommu *iommu)
iommu->stored_l2[i] = iommu_read_l2(iommu, i);
}
amd_iommu_erratum_746_workaround(iommu);
return pci_enable_device(iommu->dev);
}