diff options
| author | Fenghua Yu <fenghua.yu@intel.com> | 2009-04-24 17:30:20 -0700 |
|---|---|---|
| committer | David Woodhouse <David.Woodhouse@intel.com> | 2009-04-29 06:54:34 +0100 |
| commit | 4ed0d3e6c64cfd9ba4ceb2099b10d1cf8ece4320 (patch) | |
| tree | 950bacfaf57040aafbcc2ea9b52eb171d35c23bd /drivers/pci/dmar.c | |
| parent | 091069740304c979f957ceacec39c461d0192158 (diff) | |
| download | lwn-4ed0d3e6c64cfd9ba4ceb2099b10d1cf8ece4320.tar.gz lwn-4ed0d3e6c64cfd9ba4ceb2099b10d1cf8ece4320.zip | |
Intel IOMMU Pass Through Support
The patch adds kernel parameter intel_iommu=pt to set up pass through
mode in context mapping entry. This disables DMAR in linux kernel; but
KVM still runs on VT-d and interrupt remapping still works.
In this mode, kernel uses swiotlb for DMA API functions but other VT-d
functionalities are enabled for KVM. KVM always uses multi level
translation page table in VT-d. By default, pass though mode is disabled
in kernel.
This is useful when people don't want to enable VT-d DMAR in kernel but
still want to use KVM and interrupt remapping for reasons like DMAR
performance concern or debug purpose.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Weidong Han <weidong@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'drivers/pci/dmar.c')
| -rw-r--r-- | drivers/pci/dmar.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c index fa3a11365ec3..d3d86b749eee 100644 --- a/drivers/pci/dmar.c +++ b/drivers/pci/dmar.c @@ -515,6 +515,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd) u32 ver; static int iommu_allocated = 0; int agaw = 0; + int msagaw = 0; iommu = kzalloc(sizeof(*iommu), GFP_KERNEL); if (!iommu) @@ -535,12 +536,20 @@ int alloc_iommu(struct dmar_drhd_unit *drhd) agaw = iommu_calculate_agaw(iommu); if (agaw < 0) { printk(KERN_ERR - "Cannot get a valid agaw for iommu (seq_id = %d)\n", + "Cannot get a valid agaw for iommu (seq_id = %d)\n", + iommu->seq_id); + goto error; + } + msagaw = iommu_calculate_max_sagaw(iommu); + if (msagaw < 0) { + printk(KERN_ERR + "Cannot get a valid max agaw for iommu (seq_id = %d)\n", iommu->seq_id); goto error; } #endif iommu->agaw = agaw; + iommu->msagaw = msagaw; /* the registers might be more than one page */ map_size = max_t(int, ecap_max_iotlb_offset(iommu->ecap), |