From 4ed0d3e6c64cfd9ba4ceb2099b10d1cf8ece4320 Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Fri, 24 Apr 2009 17:30:20 -0700 Subject: 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 Acked-by: Weidong Han Signed-off-by: David Woodhouse --- include/linux/intel-iommu.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/intel-iommu.h') diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index aa8c53171233..7246971a7feb 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -120,6 +120,7 @@ static inline void dmar_writeq(void __iomem *addr, u64 val) (ecap_iotlb_offset(e) + ecap_niotlb_iunits(e) * 16) #define ecap_coherent(e) ((e) & 0x1) #define ecap_qis(e) ((e) & 0x2) +#define ecap_pass_through(e) ((e >> 6) & 0x1) #define ecap_eim_support(e) ((e >> 4) & 0x1) #define ecap_ir_support(e) ((e >> 3) & 0x1) #define ecap_max_handle_mask(e) ((e >> 20) & 0xf) @@ -302,6 +303,7 @@ struct intel_iommu { spinlock_t register_lock; /* protect register handling */ int seq_id; /* sequence id of the iommu */ int agaw; /* agaw of this iommu */ + int msagaw; /* max sagaw of this iommu */ unsigned int irq; unsigned char name[13]; /* Device Name */ -- cgit v1.2.3-59-g8ed1b