[PATCH Kernel v18 6/7] vfio iommu: Add migration capability to report supported features

[Kirti Wankhede]

Added migration capability in IOMMU info chain.
User application should check IOMMU info chain for migration capability
to use dirty page tracking feature provided by kernel module.

Signed-off-by: Kirti Wankhede <address@hidden>
---
 drivers/vfio/vfio_iommu_type1.c | 15 +++++++++++++++
 include/uapi/linux/vfio.h       | 14 ++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 8b27faf1ec38..b38d278d7bff 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2378,6 +2378,17 @@ static int vfio_iommu_iova_build_caps(struct vfio_iommu 
*iommu,
        return ret;
 }
 
+static int vfio_iommu_migration_build_caps(struct vfio_info_cap *caps)
+{
+       struct vfio_iommu_type1_info_cap_migration cap_mig;
+
+       cap_mig.header.id = VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION;
+       cap_mig.header.version = 1;
+       cap_mig.flags = VFIO_IOMMU_INFO_CAPS_MIGRATION_DIRTY_PAGE_TRACK;
+
+       return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig));
+}
+
 static long vfio_iommu_type1_ioctl(void *iommu_data,
                                   unsigned int cmd, unsigned long arg)
 {
@@ -2427,6 +2438,10 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
                if (ret)
                        return ret;
 
+               ret = vfio_iommu_migration_build_caps(&caps);
+               if (ret)
+                       return ret;
+
                if (caps.size) {
                        info.flags |= VFIO_IOMMU_INFO_CAPS;
 
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index e3cbf8b78623..df9ce8aaafab 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1013,6 +1013,20 @@ struct vfio_iommu_type1_info_cap_iova_range {
        struct  vfio_iova_range iova_ranges[];
 };
 
+/*
+ * The migration capability allows to report supported features for migration.
+ *
+ * The structures below define version 1 of this capability.
+ */
+#define VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION  1
+
+struct vfio_iommu_type1_info_cap_migration {
+       struct  vfio_info_cap_header header;
+       __u32   flags;
+       /* supports dirty page tracking */
+#define VFIO_IOMMU_INFO_CAPS_MIGRATION_DIRTY_PAGE_TRACK        (1 << 0)
+};
+
 #define VFIO_IOMMU_GET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12)
 
 /**
-- 
2.7.0