The domain->ops validation was added, as a precaution, for mixed-driver systems. Per Robin's remarks, * While bus_set_iommu() still exists, the core code prevents multiple drivers from registering, so we can't really run into a situation of having a mixed-driver system: https://lore.kernel.org/kvm/6e1280c5-4b22-ebb3-3912-6c72bc169982@xxxxxxx/ * And there's plenty more significant problems than this to fix; in future when many can be permitted, we will rely on the IOMMU core code to check the domain->ops: https://lore.kernel.org/kvm/6575de6d-94ba-c427-5b1e-967750ddff23@xxxxxxx/ So remove the check in VFIO for simplicity. Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx> Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx> --- drivers/vfio/vfio_iommu_type1.c | 32 +++++++++++--------------------- 1 file changed, 11 insertions(+), 21 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index f4e3b423a453..11be5f95580b 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -2277,29 +2277,19 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, domain->domain->ops->enforce_cache_coherency( domain->domain); - /* - * Try to match an existing compatible domain. We don't want to - * preclude an IOMMU driver supporting multiple bus_types and being - * able to include different bus_types in the same IOMMU domain, so - * we test whether the domains use the same iommu_ops rather than - * testing if they're on the same bus_type. - */ + /* Try to match an existing compatible domain */ list_for_each_entry(d, &iommu->domain_list, next) { - if (d->domain->ops == domain->domain->ops) { - iommu_detach_group(domain->domain, group->iommu_group); - if (!iommu_attach_group(d->domain, - group->iommu_group)) { - list_add(&group->next, &d->group_list); - iommu_domain_free(domain->domain); - kfree(domain); - goto done; - } - - ret = iommu_attach_group(domain->domain, - group->iommu_group); - if (ret) - goto out_domain; + iommu_detach_group(domain->domain, group->iommu_group); + if (!iommu_attach_group(d->domain, group->iommu_group)) { + list_add(&group->next, &d->group_list); + iommu_domain_free(domain->domain); + kfree(domain); + goto done; } + + ret = iommu_attach_group(domain->domain, group->iommu_group); + if (ret) + goto out_domain; } vfio_test_domain_fgsp(domain); -- 2.17.1
