On Wed, Mar 25, 2020 at 05:09:07AM +0800, Kirti Wankhede wrote:
Added .save_live_pending, .save_live_iterate and .save_live_complete_precopy
functions. These functions handles pre-copy and stop-and-copy phase.
In _SAVING|_RUNNING device state or pre-copy phase:
- read pending_bytes. If pending_bytes > 0, go through below steps.
- read data_offset - indicates kernel driver to write data to staging
buffer.
- read data_size - amount of data in bytes written by vendor driver in
migration region.
I think we should change the sequence of reading data_size and
data_offset. see the next comment below.
- read data_size bytes of data from data_offset in the migration region.
- Write data packet to file stream as below:
{VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data,
VFIO_MIG_FLAG_END_OF_STATE }
In _SAVING device state or stop-and-copy phase
a. read config space of device and save to migration file stream. This
doesn't need to be from vendor driver. Any other special config state
from driver can be saved as data in following iteration.
b. read pending_bytes. If pending_bytes > 0, go through below steps.
c. read data_offset - indicates kernel driver to write data to staging
buffer.
d. read data_size - amount of data in bytes written by vendor driver in
migration region.
e. read data_size bytes of data from data_offset in the migration region.
f. Write data packet as below:
{VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data}
g. iterate through steps b to f while (pending_bytes > 0)
h. Write {VFIO_MIG_FLAG_END_OF_STATE}
When data region is mapped, its user's responsibility to read data from
data_offset of data_size before moving to next steps.
Signed-off-by: Kirti Wankhede <address@hidden>
Reviewed-by: Neo Jia <address@hidden>
---
hw/vfio/migration.c | 245 +++++++++++++++++++++++++++++++++++++++++-
hw/vfio/trace-events | 6 ++
include/hw/vfio/vfio-common.h | 1 +
3 files changed, 251 insertions(+), 1 deletion(-)
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
index 033f76526e49..ecbeed5182c2 100644
--- a/hw/vfio/migration.c
+++ b/hw/vfio/migration.c
@@ -138,6 +138,137 @@ static int vfio_migration_set_state(VFIODevice *vbasedev,
uint32_t mask,
return 0;
}
+static void *find_data_region(VFIORegion *region,
+ uint64_t data_offset,
+ uint64_t data_size)
+{
+ void *ptr = NULL;
+ int i;
+
+ for (i = 0; i < region->nr_mmaps; i++) {
+ if ((data_offset >= region->mmaps[i].offset) &&
+ (data_offset < region->mmaps[i].offset + region->mmaps[i].size) &&
+ (data_size <= region->mmaps[i].size)) {
+ ptr = region->mmaps[i].mmap + (data_offset -
+ region->mmaps[i].offset);
+ break;
+ }
+ }
+ return ptr;
+}
+
+static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev)
+{
+ VFIOMigration *migration = vbasedev->migration;
+ VFIORegion *region = &migration->region;
+ uint64_t data_offset = 0, data_size = 0;
+ int ret;
+
+ ret = pread(vbasedev->fd, &data_offset, sizeof(data_offset),
+ region->fd_offset + offsetof(struct vfio_device_migration_info,
+ data_offset));
+ if (ret != sizeof(data_offset)) {
+ error_report("%s: Failed to get migration buffer data offset %d",
+ vbasedev->name, ret);
+ return -EINVAL;
+ }
+
+ ret = pread(vbasedev->fd, &data_size, sizeof(data_size),
+ region->fd_offset + offsetof(struct vfio_device_migration_info,
+ data_size));
+ if (ret != sizeof(data_size)) {
+ error_report("%s: Failed to get migration buffer data size %d",
+ vbasedev->name, ret);
+ return -EINVAL;
+ }
data_size should be read first, and if it's 0, data_offset will not
be read further.
the reasons are below:
1. if there's no data region provided by vendor driver, there's no
reason to get a valid data_offset, so reading/writing of data_offset
should fail. And this should not be treated as a migration error.
2. even if pending_bytes is 0, vfio_save_iterate() is still possible to be
called and therefore vfio_save_buffer() is called.