From: Joerg Roedel on
This patch exports the capability of the AMD IOMMU to force
cache coherency of DMA transactions through the IOMMU-API.
This is required to disable some nasty hacks in KVM when
this capability is not available.

Signed-off-by: Joerg Roedel <joerg.roedel(a)amd.com>
---
arch/x86/kernel/amd_iommu.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 29dd3b9..fa044e1 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -2572,6 +2572,11 @@ static phys_addr_t amd_iommu_iova_to_phys(struct iommu_domain *dom,
static int amd_iommu_domain_has_cap(struct iommu_domain *domain,
unsigned long cap)
{
+ switch (cap) {
+ case IOMMU_CAP_CACHE_COHERENCY:
+ return 1;
+ }
+
return 0;
}

--
1.7.0.4


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