[RFC 03/11] iommu: Introduce IOMMU_DOMAIN_MIXED

From: Eric Auger
Date: Tue Sep 27 2016 - 16:49:41 EST


We introduce a new IOMMU domain type, dubbed IOMMU_DOMAIN_MIXED.
It is bound to be used as a replacement of IOMMU_DOMAIN_UNMANAGED
when the IOMMU translates MSI addresses. Such domain hosts
"unmanaged" reserved IOVA ranges chosen by the iommu-api user,
dished out as part of alloc_iova. Rest if available for internal
iova needs such as MSI frame IOVA allocation.

Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
include/linux/iommu.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5c2673a..44fe213 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -62,6 +62,9 @@ struct iommu_domain_msi_geometry {
#define __IOMMU_DOMAIN_DMA_API (1U << 1) /* Domain for use in DMA-API
implementation */
#define __IOMMU_DOMAIN_PT (1U << 2) /* Domain is identity mapped */
+#define __IOMMU_DOMAIN_MIXED (1U << 3) /* Domain mixing unmanaged and
+ * managed IOVAS
+ */

/*
* This are the possible domain-types
@@ -71,6 +74,9 @@ struct iommu_domain_msi_geometry {
* IOMMU_DOMAIN_IDENTITY - DMA addresses are system physical addresses
* IOMMU_DOMAIN_UNMANAGED - DMA mappings managed by IOMMU-API user, used
* for VMs
+ * IOMMU_DOMAIN_MIXED - Most DMA mappings are managed by IOMMU-API
+ * users and holes are left available for
+ internal use such as MSI frame IOVA allocation
* IOMMU_DOMAIN_DMA - Internally used for DMA-API implementations.
* This flag allows IOMMU drivers to implement
* certain optimizations for these domains
@@ -80,6 +86,9 @@ struct iommu_domain_msi_geometry {
#define IOMMU_DOMAIN_UNMANAGED (__IOMMU_DOMAIN_PAGING)
#define IOMMU_DOMAIN_DMA (__IOMMU_DOMAIN_PAGING | \
__IOMMU_DOMAIN_DMA_API)
+#define IOMMU_DOMAIN_MIXED (__IOMMU_DOMAIN_MIXED | \
+ __IOMMU_DOMAIN_PAGING | \
+ __IOMMU_DOMAIN_DMA_API)

struct iommu_domain {
unsigned type;
--
1.9.1