From ccc23bb08a84f3709b08cc10ffd4e819832fae6d Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Mon, 17 Dec 2018 15:31:12 +0800 Subject: intel_iommu: dma read/write draining support Support DMA read/write draining should be easy for existing VT-d emulation since the emulation itself does not have any request queue there so we don't need to do anything to flush the un-commited queue. What we need to do is to declare the support. These capabilities are required to pass Windows SVVP test program. It is verified that when with parameters "x-aw-bits=48,caching-mode=off" we can pass the Windows SVVP test with this patch applied. Otherwise we'll fail with: IOMMU[0] - DWD (DMA write draining) not supported IOMMU[0] - DWD (DMA read draining) not supported Segment 0 has no DMA remapping capable IOMMU units However since these bits are not declared support for QEMU<=3.1, we'll need a compatibility bit for it and we turn this on by default only for QEMU>=4.0. Please refer to VT-d spec 6.5.4 for more information. CC: Yu Wang Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1654550 Signed-off-by: Peter Xu Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- include/hw/i386/intel_iommu.h | 1 + include/hw/i386/pc.h | 5 +++++ 2 files changed, 6 insertions(+) (limited to 'include/hw') diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h index ed4e758..a321cc9 100644 --- a/include/hw/i386/intel_iommu.h +++ b/include/hw/i386/intel_iommu.h @@ -245,6 +245,7 @@ struct IntelIOMMUState { OnOffAuto intr_eim; /* Toggle for EIM cabability */ bool buggy_eim; /* Force buggy EIM unless eim=off */ uint8_t aw_bits; /* Host/IOVA address width (in bits) */ + bool dma_drain; /* Whether DMA r/w draining enabled */ /* * Protects IOMMU states in general. Currently it protects the diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 9d29c4b..c7c0c94 100644 --- a/include/hw/i386/pc.h +++ b/include/hw/i386/pc.h @@ -296,6 +296,11 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *); #define PC_COMPAT_3_1 \ HW_COMPAT_3_1 \ + {\ + .driver = "intel-iommu",\ + .property = "dma-drain",\ + .value = "off",\ + }, #define PC_COMPAT_3_0 \ HW_COMPAT_3_0 \ -- cgit v1.1