On Tue, 9 Jul 2019 15:19:13 +0530
Kirti Wankhede <kwankh...@nvidia.com> wrote:
> VM state change handler gets called on change in VM's state. This is used to
> set
> VFIO device state to _RUNNING.
> VM state change handler, migration state change handler and log_sync listener
> are called asynchronously, which sometimes lead to data corruption in
> migration
> region. Initialised mutex that is used to serialize operations on migration
> data
> region during saving state.
>
> Signed-off-by: Kirti Wankhede <kwankh...@nvidia.com>
> Reviewed-by: Neo Jia <c...@nvidia.com>
> ---
> hw/vfio/migration.c | 64
> +++++++++++++++++++++++++++++++++++++++++++
> hw/vfio/trace-events | 2 ++
> include/hw/vfio/vfio-common.h | 4 +++
> 3 files changed, 70 insertions(+)
>
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index a2cfbd5af2e1..c01f08b659d0 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -78,6 +78,60 @@ err:
> return ret;
> }
>
> +static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t state)
> +{
> + VFIOMigration *migration = vbasedev->migration;
> + VFIORegion *region = &migration->region.buffer;
> + uint32_t device_state;
> + int ret = 0;
> +
> + device_state = (state & VFIO_DEVICE_STATE_MASK) |
> + (vbasedev->device_state & ~VFIO_DEVICE_STATE_MASK);
> +
> + if ((device_state & VFIO_DEVICE_STATE_MASK) ==
> VFIO_DEVICE_STATE_INVALID) {
> + return -EINVAL;
> + }
> +
> + ret = pwrite(vbasedev->fd, &device_state, sizeof(device_state),
> + region->fd_offset + offsetof(struct
> vfio_device_migration_info,
> + device_state));
> + if (ret < 0) {
> + error_report("%s: Failed to set device state %d %s",
> + vbasedev->name, ret, strerror(errno));
> + return ret;
> + }
> +
> + vbasedev->device_state = device_state;
Do we need to re-read device_state after error? We defined _SAVING |
_RESUMING as STATE_INVALID, is that only for user writes, ie. the
device can never transition to that state to indicate a fault? I was
thinking that was one if its use cases. Thanks,
Alex
> + trace_vfio_migration_set_state(vbasedev->name, device_state);
> + return 0;
> +}
> +
> +static void vfio_vmstate_change(void *opaque, int running, RunState state)
> +{
> + VFIODevice *vbasedev = opaque;
> +
> + if ((vbasedev->vm_running != running)) {
> + int ret;
> + uint32_t dev_state;
> +
> + if (running) {
> + dev_state = VFIO_DEVICE_STATE_RUNNING;
> + } else {
> + dev_state = (vbasedev->device_state & VFIO_DEVICE_STATE_MASK) &
> + ~VFIO_DEVICE_STATE_RUNNING;
> + }
> +
> + ret = vfio_migration_set_state(vbasedev, dev_state);
> + if (ret) {
> + error_report("%s: Failed to set device state 0x%x",
> + vbasedev->name, dev_state);
> + }
> + vbasedev->vm_running = running;
> + trace_vfio_vmstate_change(vbasedev->name, running,
> RunState_str(state),
> + dev_state);
> + }
> +}
> +
> static int vfio_migration_init(VFIODevice *vbasedev,
> struct vfio_region_info *info)
> {
> @@ -93,6 +147,11 @@ static int vfio_migration_init(VFIODevice *vbasedev,
> return ret;
> }
>
> + qemu_mutex_init(&vbasedev->migration->lock);
> +
> + vbasedev->vm_state =
> qemu_add_vm_change_state_handler(vfio_vmstate_change,
> + vbasedev);
> +
> return 0;
> }
>
> @@ -135,11 +194,16 @@ void vfio_migration_finalize(VFIODevice *vbasedev)
> return;
> }
>
> + if (vbasedev->vm_state) {
> + qemu_del_vm_change_state_handler(vbasedev->vm_state);
> + }
> +
> if (vbasedev->migration_blocker) {
> migrate_del_blocker(vbasedev->migration_blocker);
> error_free(vbasedev->migration_blocker);
> }
>
> + qemu_mutex_destroy(&vbasedev->migration->lock);
> vfio_migration_region_exit(vbasedev);
> g_free(vbasedev->migration);
> }
> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> index 191a726a1312..3d15bacd031a 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -146,3 +146,5 @@ vfio_display_edid_write_error(void) ""
>
> # migration.c
> vfio_migration_probe(char *name, uint32_t index) " (%s) Region %d"
> +vfio_migration_set_state(char *name, uint32_t state) " (%s) state %d"
> +vfio_vmstate_change(char *name, int running, const char *reason, uint32_t
> dev_state) " (%s) running %d reason %s device state %d"
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 152da3f8d6f3..f6c70db3a9c1 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -29,6 +29,7 @@
> #ifdef CONFIG_LINUX
> #include <linux/vfio.h>
> #endif
> +#include "sysemu/sysemu.h"
>
> #define VFIO_MSG_PREFIX "vfio %s: "
>
> @@ -124,6 +125,9 @@ typedef struct VFIODevice {
> unsigned int flags;
> VFIOMigration *migration;
> Error *migration_blocker;
> + uint32_t device_state;
> + VMChangeStateEntry *vm_state;
> + int vm_running;
> } VFIODevice;
>
> struct VFIODeviceOps {
