From d9bcfe28139d190ed9847217dd309296580c2b7e Mon Sep 17 00:00:00 2001
From: Alex Williamson <alex.williamson@redhat.com>
Date: Fri, 10 Apr 2015 16:34:13 +0200
Subject: [PATCH 07/14] vfio: Use vfio type1 v2 IOMMU interface

Message-id: <20150410163413.15324.90697.stgit@gimli.home>
Patchwork-id: 64787
O-Subject: [RHEL7.2 qemu-kvm PATCH 7/8] vfio: Use vfio type1 v2 IOMMU interface
Bugzilla: 1210508
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Bandan Das <bsd@redhat.com>

Upstream: 2e6e697e166568fdd09ceaa8c7c8c8c53a5e345b

The difference between v1 and v2 is fairly subtle, simply more
deterministic behavior for unmaps.  The v1 interface allows the user
to attempt to unmap sub-regions of previous mappings, returning
success with zero size if unable to comply.  This was a reflection of
the underlying IOMMU API.  The v2 interface requires that the user
may only unmap fully contained mappings, ie. an unmap cannot intersect
or bisect a previous mapping, but may cover multiple mappings.  QEMU
never made use of the sub-region v1 support anyway, so we can support
either v1 or v2.  We'll favor v2 since it's newer.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/misc/vfio.c             | 8 ++++++--
 linux-headers/linux/vfio.h | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index 607dbf4..d06b485 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -3312,7 +3312,10 @@ static int vfio_connect_container(VFIOGroup *group)
     container = g_malloc0(sizeof(*container));
     container->fd = fd;
 
-    if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU)) {
+    if (ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1_IOMMU) ||
+        ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU)) {
+        bool v2 = !!ioctl(fd, VFIO_CHECK_EXTENSION, VFIO_TYPE1v2_IOMMU);
+
         ret = ioctl(group->fd, VFIO_GROUP_SET_CONTAINER, &fd);
         if (ret) {
             error_report("vfio: failed to set group container: %m");
@@ -3321,7 +3324,8 @@ static int vfio_connect_container(VFIOGroup *group)
             return -errno;
         }
 
-        ret = ioctl(fd, VFIO_SET_IOMMU, VFIO_TYPE1_IOMMU);
+        ret = ioctl(fd, VFIO_SET_IOMMU,
+                    v2 ? VFIO_TYPE1v2_IOMMU : VFIO_TYPE1_IOMMU);
         if (ret) {
             error_report("vfio: failed to set iommu for container: %m");
             g_free(container);
diff --git a/linux-headers/linux/vfio.h b/linux-headers/linux/vfio.h
index d341312..7919c76 100644
--- a/linux-headers/linux/vfio.h
+++ b/linux-headers/linux/vfio.h
@@ -22,6 +22,7 @@
 /* Extensions */
 
 #define VFIO_TYPE1_IOMMU		1
+#define VFIO_TYPE1v2_IOMMU		3
 
 /*
  * The IOCTL interface is designed for extensibility by embedding the
-- 
1.8.3.1