In preparation to using the dirty tracking UAPI, probe whether the IOMMU supports dirty tracking. This is done via the data stored in hiod::caps::hw_caps initialized from GET_HW_INFO.
Qemu doesn't know if VF dirty tracking is supported when allocating hardware pagetable in iommufd_cdev_autodomains_get(). This is because VFIODevice migration state hasn't been initialized *yet* hence it can't pick between VF dirty tracking vs IOMMU dirty tracking. So, if IOMMU supports dirty tracking it always creates HWPTs with IOMMU_HWPT_ALLOC_DIRTY_TRACKING even if later on VFIOMigration decides to use VF dirty tracking instead. Signed-off-by: Joao Martins <joao.m.mart...@oracle.com> --- include/hw/vfio/vfio-common.h | 1 + hw/vfio/iommufd.c | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index 4e44b26d3c45..7e530c7869dc 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -97,6 +97,7 @@ typedef struct IOMMUFDBackend IOMMUFDBackend; typedef struct VFIOIOASHwpt { uint32_t hwpt_id; + uint32_t hwpt_flags; QLIST_HEAD(, VFIODevice) device_list; QLIST_ENTRY(VFIOIOASHwpt) next; } VFIOIOASHwpt; diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c index bb44d948c735..2e5c207bbca0 100644 --- a/hw/vfio/iommufd.c +++ b/hw/vfio/iommufd.c @@ -110,6 +110,11 @@ static void iommufd_cdev_unbind_and_disconnect(VFIODevice *vbasedev) iommufd_backend_disconnect(vbasedev->iommufd); } +static bool iommufd_hwpt_dirty_tracking(VFIOIOASHwpt *hwpt) +{ + return hwpt && hwpt->hwpt_flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING; +} + static int iommufd_cdev_getfd(const char *sysfs_path, Error **errp) { ERRP_GUARD(); @@ -246,6 +251,17 @@ static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev, } } + /* + * This is quite early and VFIO Migration state isn't yet fully + * initialized, thus rely only on IOMMU hardware capabilities as to + * whether IOMMU dirty tracking is going to be requested. Later + * vfio_migration_realize() may decide to use VF dirty tracking + * instead. + */ + if (vbasedev->hiod->caps.hw_caps & IOMMU_HW_CAP_DIRTY_TRACKING) { + flags = IOMMU_HWPT_ALLOC_DIRTY_TRACKING; + } + if (!iommufd_backend_alloc_hwpt(iommufd, vbasedev->devid, container->ioas_id, flags, IOMMU_HWPT_DATA_NONE, 0, NULL, @@ -255,6 +271,7 @@ static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev, hwpt = g_malloc0(sizeof(*hwpt)); hwpt->hwpt_id = hwpt_id; + hwpt->hwpt_flags = flags; QLIST_INIT(&hwpt->device_list); ret = iommufd_cdev_attach_ioas_hwpt(vbasedev, hwpt->hwpt_id, errp); @@ -267,6 +284,8 @@ static bool iommufd_cdev_autodomains_get(VFIODevice *vbasedev, vbasedev->hwpt = hwpt; QLIST_INSERT_HEAD(&hwpt->device_list, vbasedev, hwpt_next); QLIST_INSERT_HEAD(&container->hwpt_list, hwpt, next); + container->bcontainer.dirty_pages_supported |= + iommufd_hwpt_dirty_tracking(hwpt); return true; } -- 2.17.2