vfio/spapr: Allow fallback to SPAPR TCE IOMMU v1

The vfio_iommu_spapr_tce driver advertises kernel's support for
v1 and v2 IOMMU support, however it is not always possible to use
the requested IOMMU type. For example, a pseries host platform does not
support dynamic DMA windows so v2 cannot initialize and QEMU fails to
start.

This adds a fallback to the v1 IOMMU if v2 cannot be used.

Fixes: 318f67ce13 ("vfio: spapr: Add DMA memory preregistering (SPAPR IOMMU v2)")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Alexey Kardashevskiy 2017-12-13 10:19:33 -07:00 committed by Alex Williamson
parent f7f9c7b232
commit c6e7958eb7

View file

@ -1042,6 +1042,11 @@ static int vfio_connect_container(VFIOGroup *group, AddressSpace *as,
container->iommu_type =
v2 ? VFIO_SPAPR_TCE_v2_IOMMU : VFIO_SPAPR_TCE_IOMMU;
ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
if (ret) {
container->iommu_type = VFIO_SPAPR_TCE_IOMMU;
v2 = false;
ret = ioctl(fd, VFIO_SET_IOMMU, container->iommu_type);
}
if (ret) {
error_setg_errno(errp, errno, "failed to set iommu for container");
ret = -errno;