[PATCH v8 22/29] vfio: VFIO_IOMMU_ATTACH/DETACH_PASID_TABLE

[Eric Auger <eric.auger@redhat.com>]

From: "Liu, Yi L" <yi.l.liu@linux.intel.com>

This patch adds VFIO_IOMMU_ATTACH/DETACH_PASID_TABLE ioctl
which aims to pass/withdraw the virtual iommu guest configuration
to/from the VFIO driver downto to the iommu subsystem.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Liu, Yi L <yi.l.liu@linux.intel.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>

---
v6 -> v7:
- add a comment related to VFIO_IOMMU_DETACH_PASID_TABLE

v3 -> v4:
- restore ATTACH/DETACH
- add unwind on failure

v2 -> v3:
- s/BIND_PASID_TABLE/SET_PASID_TABLE

v1 -> v2:
- s/BIND_GUEST_STAGE/BIND_PASID_TABLE
- remove the struct device arg
---
 drivers/vfio/vfio_iommu_type1.c | 53 +++++++++++++++++++++++++++++++++
 include/uapi/linux/vfio.h       | 22 ++++++++++++++
 2 files changed, 75 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 3ddc375e7063..b2d609d6fe83 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1758,6 +1758,43 @@ static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu)
 	return ret;
 }
 
+static void
+vfio_detach_pasid_table(struct vfio_iommu *iommu)
+{
+	struct vfio_domain *d;
+
+	mutex_lock(&iommu->lock);
+
+	list_for_each_entry(d, &iommu->domain_list, next) {
+		iommu_detach_pasid_table(d->domain);
+	}
+	mutex_unlock(&iommu->lock);
+}
+
+static int
+vfio_attach_pasid_table(struct vfio_iommu *iommu,
+			struct vfio_iommu_type1_attach_pasid_table *ustruct)
+{
+	struct vfio_domain *d;
+	int ret = 0;
+
+	mutex_lock(&iommu->lock);
+
+	list_for_each_entry(d, &iommu->domain_list, next) {
+		ret = iommu_attach_pasid_table(d->domain, &ustruct->config);
+		if (ret)
+			goto unwind;
+	}
+	goto unlock;
+unwind:
+	list_for_each_entry_continue_reverse(d, &iommu->domain_list, next) {
+		iommu_detach_pasid_table(d->domain);
+	}
+unlock:
+	mutex_unlock(&iommu->lock);
+	return ret;
+}
+
 static long vfio_iommu_type1_ioctl(void *iommu_data,
 				   unsigned int cmd, unsigned long arg)
 {
@@ -1828,6 +1865,22 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
 
 		return copy_to_user((void __user *)arg, &unmap, minsz) ?
 			-EFAULT : 0;
+	} else if (cmd == VFIO_IOMMU_ATTACH_PASID_TABLE) {
+		struct vfio_iommu_type1_attach_pasid_table ustruct;
+
+		minsz = offsetofend(struct vfio_iommu_type1_attach_pasid_table,
+				    config);
+
+		if (copy_from_user(&ustruct, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (ustruct.argsz < minsz || ustruct.flags)
+			return -EINVAL;
+
+		return vfio_attach_pasid_table(iommu, &ustruct);
+	} else if (cmd == VFIO_IOMMU_DETACH_PASID_TABLE) {
+		vfio_detach_pasid_table(iommu);
+		return 0;
 	}
 
 	return -ENOTTY;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 8f10748dac79..4316dd8cb5b5 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -14,6 +14,7 @@
 
 #include <linux/types.h>
 #include <linux/ioctl.h>
+#include <linux/iommu.h>
 
 #define VFIO_API_VERSION	0
 
@@ -763,6 +764,27 @@ struct vfio_iommu_type1_dma_unmap {
 #define VFIO_IOMMU_ENABLE	_IO(VFIO_TYPE, VFIO_BASE + 15)
 #define VFIO_IOMMU_DISABLE	_IO(VFIO_TYPE, VFIO_BASE + 16)
 
+/**
+ * VFIO_IOMMU_ATTACH_PASID_TABLE - _IOWR(VFIO_TYPE, VFIO_BASE + 22,
+ *			struct vfio_iommu_type1_attach_pasid_table)
+ *
+ * Passes the PASID table to the host. Calling ATTACH_PASID_TABLE
+ * while a table is already installed is allowed: it replaces the old
+ * table. DETACH does a comprehensive tear down of the nested mode.
+ */
+struct vfio_iommu_type1_attach_pasid_table {
+	__u32	argsz;
+	__u32	flags;
+	struct iommu_pasid_table_config config;
+};
+#define VFIO_IOMMU_ATTACH_PASID_TABLE	_IO(VFIO_TYPE, VFIO_BASE + 22)
+
+/**
+ * VFIO_IOMMU_DETACH_PASID_TABLE - - _IOWR(VFIO_TYPE, VFIO_BASE + 23)
+ * Detaches the PASID table
+ */
+#define VFIO_IOMMU_DETACH_PASID_TABLE	_IO(VFIO_TYPE, VFIO_BASE + 23)
+
 /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
 
 /*
-- 
2.20.1