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[Qemu-devel] [PATCH] vfio: Use vfio type1 v2 IOMMU interface
From: |
Alex Williamson |
Subject: |
[Qemu-devel] [PATCH] vfio: Use vfio type1 v2 IOMMU interface |
Date: |
Fri, 06 Feb 2015 15:31:07 -0700 |
User-agent: |
StGIT/0.14.3 |
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 <address@hidden>
---
hw/vfio/common.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index b230ef1..c5d1551 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -662,7 +662,10 @@ static int vfio_connect_container(VFIOGroup *group,
AddressSpace *as)
container = g_malloc0(sizeof(*container));
container->space = space;
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");
@@ -670,7 +673,8 @@ static int vfio_connect_container(VFIOGroup *group,
AddressSpace *as)
goto free_container_exit;
}
- 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");
ret = -errno;
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