On 12.02.2025 11:55, Cédric Le Goater wrote:
On 1/30/25 11:08, Maciej S. Szmigiero wrote:
From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com>
Add support for VFIOMultifd data structure that will contain most of the
receive-side data together with its init/cleanup methods.
Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com>
---
hw/vfio/migration.c | 52 +++++++++++++++++++++++++++++++++--
include/hw/vfio/vfio-common.h | 5 ++++
2 files changed, 55 insertions(+), 2 deletions(-)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 3211041939c6..bcdf204d5cf4 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -300,6 +300,9 @@ typedef struct VFIOStateBuffer {
size_t len;
} VFIOStateBuffer;
+typedef struct VFIOMultifd {
+} VFIOMultifd;
+
static void vfio_state_buffer_clear(gpointer data)
{
VFIOStateBuffer *lb = data;
@@ -398,6 +401,18 @@ static int vfio_load_device_config_state(QEMUFile *f, void
*opaque)
return qemu_file_get_error(f);
}
+static VFIOMultifd *vfio_multifd_new(void)
+{
+ VFIOMultifd *multifd = g_new(VFIOMultifd, 1);
+
+ return multifd;
+}
+
+static void vfio_multifd_free(VFIOMultifd *multifd)
+{
+ g_free(multifd);
+}
+
static void vfio_migration_cleanup(VFIODevice *vbasedev)
{
VFIOMigration *migration = vbasedev->migration;
@@ -785,14 +800,47 @@ static void vfio_save_state(QEMUFile *f, void *opaque)
static int vfio_load_setup(QEMUFile *f, void *opaque, Error **errp)
{
VFIODevice *vbasedev = opaque;
+ VFIOMigration *migration = vbasedev->migration;
+ int ret;
+
+ /*
+ * Make a copy of this setting at the start in case it is changed
+ * mid-migration.
+ */
+ if (vbasedev->migration_multifd_transfer == ON_OFF_AUTO_AUTO) {
+ migration->multifd_transfer = vfio_multifd_transfer_supported();
Attribute "migration->multifd_transfer" is not necessary. It can be
replaced by a small inline helper testing pointer migration->multifd
and this routine can use a local variable instead.
It's necessary for the send side since it does not need/allocate VFIOMultifd
at migration->multifd, so this (receive) side can use it for commonality too.
I don't think the '_transfer' suffix adds much to the understanding.
The migration->multifd was already taken by VFIOMultifd struct, but
it could use other name (migration->multifd_switch? migration->multifd_on?).
+ } else {
+ migration->multifd_transfer =
+ vbasedev->migration_multifd_transfer == ON_OFF_AUTO_ON;
+ }
+
+ if (migration->multifd_transfer && !vfio_multifd_transfer_supported()) {
+ error_setg(errp,
+ "%s: Multifd device transfer requested but unsupported in the
current config",
+ vbasedev->name);
+ return -EINVAL;
+ }
The above checks are also introduced in vfio_save_setup(). Please
implement a common routine vfio_multifd_is_enabled() or some other
name.
Done (as common vfio_multifd_transfer_setup()).
+ ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
+ migration->device_state, errp);
+ if (ret) {
+ return ret;
+ }
+
+ if (migration->multifd_transfer) {
+ assert(!migration->multifd);
+ migration->multifd = vfio_multifd_new();
+ }
- return vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RESUMING,
- vbasedev->migration->device_state, errp);
+ return 0;
}
static int vfio_load_cleanup(void *opaque)
{
VFIODevice *vbasedev = opaque;
+ VFIOMigration *migration = vbasedev->migration;
+
+ g_clear_pointer(&migration->multifd, vfio_multifd_free);
please add a vfio_multifd_cleanup() routine.
Done.
vfio_migration_cleanup(vbasedev);
trace_vfio_load_cleanup(vbasedev->name);
diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
index 153d03745dc7..c0c9c0b1b263 100644
--- a/include/hw/vfio/vfio-common.h
+++ b/include/hw/vfio/vfio-common.h
@@ -61,6 +61,8 @@ typedef struct VFIORegion {
uint8_t nr; /* cache the region number for debug */
} VFIORegion;
+typedef struct VFIOMultifd VFIOMultifd;
+
typedef struct VFIOMigration {
struct VFIODevice *vbasedev;
VMChangeStateEntry *vm_state;
@@ -72,6 +74,8 @@ typedef struct VFIOMigration {
uint64_t mig_flags;
uint64_t precopy_init_size;
uint64_t precopy_dirty_size;
+ bool multifd_transfer;
+ VFIOMultifd *multifd;
bool initial_data_sent;
bool event_save_iterate_started;
@@ -133,6 +137,7 @@ typedef struct VFIODevice {
bool no_mmap;
bool ram_block_discard_allowed;
OnOffAuto enable_migration;
+ OnOffAuto migration_multifd_transfer;
This property should be added at the end of the series, with documentation,
and used in the vfio_multifd_some_name() routine I mentioned above.
The property behind this variable *is* in fact introduced at the end of the
series -
in a commit called "vfio/migration: Add x-migration-multifd-transfer VFIO
property"
after which there are only commits adding the related compat entry and a VFIO
developer doc update.
The variable itself needs to be introduced earlier since various newly
introduced code blocks depend on its value to only get activated when multifd
transfer is enabled.
Thanks,
C.
Thanks,
Maciej
