From cf254988a50d4164c86a356c80b8d3ae0ccaa005 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Mon, 9 Nov 2020 11:56:02 -0700 Subject: vfio: Make migration support experimental Support for migration of vfio devices is still in flux. Developers are attempting to add support for new devices and new architectures, but none are yet readily available for validation. We have concerns whether we're transferring device resources at the right point in the migration, whether we're guaranteeing that updates during pre-copy are migrated, and whether we can provide bit-stream compatibility should any of this change. Even the question of whether devices should participate in dirty page tracking during pre-copy seems contentious. In short, migration support has not had enough soak time and it feels premature to mark it as supported. Create an experimental option such that we can continue to develop. [Retaining previous acks/reviews for a previously identical code change with different specifics in the commit log.] Reviewed-by: Dr. David Alan Gilbert Acked-by: Cornelia Huck Signed-off-by: Alex Williamson --- hw/vfio/migration.c | 2 +- hw/vfio/pci.c | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) (limited to 'hw') diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index 55261562d4..00daa50ed8 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -882,7 +882,7 @@ int vfio_migration_probe(VFIODevice *vbasedev, Error **errp) Error *local_err = NULL; int ret = -ENOTSUP; - if (!container->dirty_pages_supported) { + if (!vbasedev->enable_migration || !container->dirty_pages_supported) { goto add_blocker; } diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index 58c0ce8971..1349b900e5 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -3194,6 +3194,8 @@ static Property vfio_pci_dev_properties[] = { VFIO_FEATURE_ENABLE_REQ_BIT, true), DEFINE_PROP_BIT("x-igd-opregion", VFIOPCIDevice, features, VFIO_FEATURE_ENABLE_IGD_OPREGION_BIT, false), + DEFINE_PROP_BOOL("x-enable-migration", VFIOPCIDevice, + vbasedev.enable_migration, false), DEFINE_PROP_BOOL("x-no-mmap", VFIOPCIDevice, vbasedev.no_mmap, false), DEFINE_PROP_BOOL("x-balloon-allowed", VFIOPCIDevice, vbasedev.ram_block_discard_allowed, false), -- cgit v1.2.3-55-g7522 From bb0990d1740f6dced5b50a923677034c9399c213 Mon Sep 17 00:00:00 2001 From: Kirti Wankhede Date: Mon, 23 Nov 2020 19:53:19 +0530 Subject: vfio: Change default dirty pages tracking behavior during migration By default dirty pages tracking is enabled during iterative phase (pre-copy phase). Added per device opt-out option 'x-pre-copy-dirty-page-tracking' to disable dirty pages tracking during iterative phase. If the option 'x-pre-copy-dirty-page-tracking=off' is set for any VFIO device, dirty pages tracking during iterative phase will be disabled. Signed-off-by: Kirti Wankhede Signed-off-by: Alex Williamson --- hw/vfio/common.c | 11 +++++++---- hw/vfio/pci.c | 3 +++ include/hw/vfio/vfio-common.h | 1 + 3 files changed, 11 insertions(+), 4 deletions(-) (limited to 'hw') diff --git a/hw/vfio/common.c b/hw/vfio/common.c index c1fdbf17f2..6ff1daa763 100644 --- a/hw/vfio/common.c +++ b/hw/vfio/common.c @@ -311,7 +311,7 @@ bool vfio_mig_active(void) return true; } -static bool vfio_devices_all_stopped_and_saving(VFIOContainer *container) +static bool vfio_devices_all_saving(VFIOContainer *container) { VFIOGroup *group; VFIODevice *vbasedev; @@ -329,8 +329,11 @@ static bool vfio_devices_all_stopped_and_saving(VFIOContainer *container) return false; } - if ((migration->device_state & VFIO_DEVICE_STATE_SAVING) && - !(migration->device_state & VFIO_DEVICE_STATE_RUNNING)) { + if (migration->device_state & VFIO_DEVICE_STATE_SAVING) { + if ((vbasedev->pre_copy_dirty_page_tracking == ON_OFF_AUTO_OFF) + && (migration->device_state & VFIO_DEVICE_STATE_RUNNING)) { + return false; + } continue; } else { return false; @@ -1125,7 +1128,7 @@ static void vfio_listerner_log_sync(MemoryListener *listener, return; } - if (vfio_devices_all_stopped_and_saving(container)) { + if (vfio_devices_all_saving(container)) { vfio_sync_dirty_bitmap(container, section); } } diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index 1349b900e5..51dc373695 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -3182,6 +3182,9 @@ static void vfio_instance_init(Object *obj) static Property vfio_pci_dev_properties[] = { DEFINE_PROP_PCI_HOST_DEVADDR("host", VFIOPCIDevice, host), DEFINE_PROP_STRING("sysfsdev", VFIOPCIDevice, vbasedev.sysfsdev), + DEFINE_PROP_ON_OFF_AUTO("x-pre-copy-dirty-page-tracking", VFIOPCIDevice, + vbasedev.pre_copy_dirty_page_tracking, + ON_OFF_AUTO_ON), DEFINE_PROP_ON_OFF_AUTO("display", VFIOPCIDevice, display, ON_OFF_AUTO_OFF), DEFINE_PROP_UINT32("xres", VFIOPCIDevice, display_xres, 0), diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index 2119872c8a..6141162d7a 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -130,6 +130,7 @@ typedef struct VFIODevice { unsigned int flags; VFIOMigration *migration; Error *migration_blocker; + OnOffAuto pre_copy_dirty_page_tracking; } VFIODevice; struct VFIODeviceOps { -- cgit v1.2.3-55-g7522