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 /arch/ia64 | |
| parent | 091069740304c979f957ceacec39c461d0192158 (diff) | |
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 'arch/ia64')
| -rw-r--r-- | arch/ia64/include/asm/iommu.h | 1 | ||||
| -rw-r--r-- | arch/ia64/kernel/pci-swiotlb.c | 2 |
2 files changed, 2 insertions, 1 deletions
diff --git a/arch/ia64/include/asm/iommu.h b/arch/ia64/include/asm/iommu.h index 0490794fe4aa..37d41ca5645a 100644 --- a/arch/ia64/include/asm/iommu.h +++ b/arch/ia64/include/asm/iommu.h @@ -9,6 +9,7 @@ extern void pci_iommu_shutdown(void); extern void no_iommu_init(void); extern int force_iommu, no_iommu; extern int iommu_detected; +extern int iommu_pass_through; extern void iommu_dma_init(void); extern void machvec_init(const char *name); diff --git a/arch/ia64/kernel/pci-swiotlb.c b/arch/ia64/kernel/pci-swiotlb.c index 285aae8431c6..223abb134105 100644 --- a/arch/ia64/kernel/pci-swiotlb.c +++ b/arch/ia64/kernel/pci-swiotlb.c @@ -46,7 +46,7 @@ void __init swiotlb_dma_init(void) void __init pci_swiotlb_init(void) { - if (!iommu_detected) { + if (!iommu_detected || iommu_pass_through) { #ifdef CONFIG_IA64_GENERIC swiotlb = 1; printk(KERN_INFO "PCI-DMA: Re-initialize machine vector.\n"); |