Commit ae2c3d95 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'iommu-fixes-v3.8-rc5' of git://

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://
  IOMMU, AMD Family15h Model10-1Fh erratum 746 Workaround
parents 325a86b6 318fe782
......@@ -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))
pci_write_config_dword(iommu->dev, 0xf0, 0x90);
pci_read_config_dword(iommu->dev, 0xf4, &value);
if (value & BIT(2))
/* 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",
/* 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);
return pci_enable_device(iommu->dev);
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