From cf254988a50d4164c86a356c80b8d3ae0ccaa005 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Mon, 9 Nov 2020 11:56:02 -0700 Subject: [PATCH] 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 ++ include/hw/vfio/vfio-common.h | 1 + 3 files changed, 4 insertions(+), 1 deletion(-) 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), diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index baeb4dcff1..2119872c8a 100644 --- a/include/hw/vfio/vfio-common.h +++ b/include/hw/vfio/vfio-common.h @@ -123,6 +123,7 @@ typedef struct VFIODevice { bool needs_reset; bool no_mmap; bool ram_block_discard_allowed; + bool enable_migration; VFIODeviceOps *ops; unsigned int num_irqs; unsigned int num_regions; -- 2.11.0