Introduce a new DOMAIN_ATTR_MSI_GEOMETRY domain attribute. It enables
to query the aperture of the IOVA window dedicated to MSIs.
x86 IOMMUs will typically expose an MSI aperture matching the 1MB
region [FEE0_0000h - FEF0_000h] corresponding to the APIC configuration
space and no support for MSI translation.
On ARM, arm-smmu(-v3) translate MSIs. Aperture is not set indicating
MSI IOVA can live everywhere in the IOVA address space
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
Suggested-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
drivers/iommu/iommu.c | 5 +++++
include/linux/iommu.h | 13 +++++++++++++
2 files changed, 18 insertions(+)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 9a2f196..617cb2b 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1485,6 +1485,7 @@ int iommu_domain_get_attr(struct iommu_domain *domain,
enum iommu_attr attr, void *data)
{
struct iommu_domain_geometry *geometry;
+ struct iommu_domain_msi_geometry *msi_geometry;
bool *paging;
int ret = 0;
u32 *count;
@@ -1495,6 +1496,10 @@ int iommu_domain_get_attr(struct iommu_domain *domain,
*geometry = domain->geometry;
break;
+ case DOMAIN_ATTR_MSI_GEOMETRY:
+ msi_geometry = data;
+ *msi_geometry = domain->msi_geometry;
+ break;
case DOMAIN_ATTR_PAGING:
paging = data;
*paging = (domain->pgsize_bitmap != 0UL);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 436dc21..ef6e047 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -52,6 +52,11 @@ struct iommu_domain_geometry {
bool force_aperture; /* DMA only allowed in mappable range? */
};
+struct iommu_domain_msi_geometry {
+ dma_addr_t aperture_start; /* First address usable for MSI IOVA */
+ dma_addr_t aperture_end; /* Last address usable for MSI IOVA */
+};
+
/* Domain feature flags */
#define __IOMMU_DOMAIN_PAGING (1U << 0) /* Support for iommu_map/unmap */
#define __IOMMU_DOMAIN_DMA_API (1U << 1) /* Domain for use in DMA-API
@@ -83,6 +88,7 @@ struct iommu_domain {
iommu_fault_handler_t handler;
void *handler_token;
struct iommu_domain_geometry geometry;
+ struct iommu_domain_msi_geometry msi_geometry;
void *iova_cookie;
};
@@ -108,6 +114,7 @@ enum iommu_cap {
enum iommu_attr {
DOMAIN_ATTR_GEOMETRY,
+ DOMAIN_ATTR_MSI_GEOMETRY,
DOMAIN_ATTR_PAGING,
DOMAIN_ATTR_WINDOWS,
DOMAIN_ATTR_FSL_PAMU_STASH,
@@ -352,6 +359,12 @@ int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
void iommu_fwspec_free(struct device *dev);
int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids);
+static inline bool iommu_domain_msi_aperture_valid(struct iommu_domain *domain)
+{
+ return (domain->msi_geometry.aperture_end >
+ domain->msi_geometry.aperture_start);
+}
+
#else /* CONFIG_IOMMU_API */
struct iommu_ops {};
--
1.9.1
--
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