From d0a8ba1957743c55547ec2ccd8cb09b84a3354d2 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 Signed-off-by: Kunkun Jiang --- 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 8546075706..033cb2b0c9 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -888,7 +888,7 @@ 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 da7c740bce..2795b8bd12 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -3192,6 +3192,8 @@ 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.balloon_allowed, false), diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h index 048731e81f..7398631d4c 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 balloon_allowed; + bool enable_migration; VFIODeviceOps *ops; unsigned int num_irqs; unsigned int num_regions; -- 2.27.0