From: Joerg Roedel <joerg.roedel@amd.com>
Date: Tue, 27 Jul 2010 15:14:24 +0000 (+0200)
Subject: x86/amd-iommu: Export cache-coherency capability
X-Git-Tag: firefly_0821_release~9833^2~1269^2^3
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=80a506b8fdcfa868bb53eb740f928217d0966fc1;p=firefly-linux-kernel-4.4.55.git

x86/amd-iommu: Export cache-coherency capability

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@amd.com>
---

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 29dd3b9f2f09..fa044e1e30a2 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;
 }