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authorWill Deacon <will.deacon@arm.com>2014-09-29 10:06:19 -0600
committerAlex Williamson <alex.williamson@redhat.com>2014-09-29 10:06:19 -0600
commitf5c9ecebaf2a2c9381973798e389cc019dd983e0 (patch)
tree0668589b668a32145609cde83473824fbd4cfe30
parentc02607aad2f9ed478eb288bcec1c00cd9df38b3c (diff)
downloadop-kernel-dev-f5c9ecebaf2a2c9381973798e389cc019dd983e0.zip
op-kernel-dev-f5c9ecebaf2a2c9381973798e389cc019dd983e0.tar.gz
vfio/iommu_type1: add new VFIO_TYPE1_NESTING_IOMMU IOMMU type
VFIO allows devices to be safely handed off to userspace by putting them behind an IOMMU configured to ensure DMA and interrupt isolation. This enables userspace KVM clients, such as kvmtool and qemu, to further map the device into a virtual machine. With IOMMUs such as the ARM SMMU, it is then possible to provide SMMU translation services to the guest operating system, which are nested with the existing translation installed by VFIO. However, enabling this feature means that the IOMMU driver must be informed that the VFIO domain is being created for the purposes of nested translation. This patch adds a new IOMMU type (VFIO_TYPE1_NESTING_IOMMU) to the VFIO type-1 driver. The new IOMMU type acts identically to the VFIO_TYPE1v2_IOMMU type, but additionally sets the DOMAIN_ATTR_NESTING attribute on its IOMMU domains. Cc: Joerg Roedel <joro@8bytes.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
-rw-r--r--drivers/vfio/vfio_iommu_type1.c30
-rw-r--r--include/uapi/linux/vfio.h3
2 files changed, 28 insertions, 5 deletions
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 0734fbe..583ccdb 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -57,7 +57,8 @@ struct vfio_iommu {
struct list_head domain_list;
struct mutex lock;
struct rb_root dma_list;
- bool v2;
+ bool v2;
+ bool nesting;
};
struct vfio_domain {
@@ -705,6 +706,15 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
goto out_free;
}
+ if (iommu->nesting) {
+ int attr = 1;
+
+ ret = iommu_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING,
+ &attr);
+ if (ret)
+ goto out_domain;
+ }
+
ret = iommu_attach_group(domain->domain, iommu_group);
if (ret)
goto out_domain;
@@ -819,17 +829,26 @@ static void *vfio_iommu_type1_open(unsigned long arg)
{
struct vfio_iommu *iommu;
- if (arg != VFIO_TYPE1_IOMMU && arg != VFIO_TYPE1v2_IOMMU)
- return ERR_PTR(-EINVAL);
-
iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
if (!iommu)
return ERR_PTR(-ENOMEM);
+ switch (arg) {
+ case VFIO_TYPE1_IOMMU:
+ break;
+ case VFIO_TYPE1_NESTING_IOMMU:
+ iommu->nesting = true;
+ case VFIO_TYPE1v2_IOMMU:
+ iommu->v2 = true;
+ break;
+ default:
+ kfree(iommu);
+ return ERR_PTR(-EINVAL);
+ }
+
INIT_LIST_HEAD(&iommu->domain_list);
iommu->dma_list = RB_ROOT;
mutex_init(&iommu->lock);
- iommu->v2 = (arg == VFIO_TYPE1v2_IOMMU);
return iommu;
}
@@ -885,6 +904,7 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
switch (arg) {
case VFIO_TYPE1_IOMMU:
case VFIO_TYPE1v2_IOMMU:
+ case VFIO_TYPE1_NESTING_IOMMU:
return 1;
case VFIO_DMA_CC_IOMMU:
if (!iommu)
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 6612974..29715d2 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -33,6 +33,9 @@
/* Check if EEH is supported */
#define VFIO_EEH 5
+/* Two-stage IOMMU */
+#define VFIO_TYPE1_NESTING_IOMMU 6 /* Implies v2 */
+
/*
* The IOCTL interface is designed for extensibility by embedding the
* structure length (argsz) and flags into structures passed between
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