On Tue, 12 Nov 2019 22:35:17 +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.
>
> Signed-off-by: Kirti Wankhede <kwankh...@nvidia.com>
> Reviewed-by: Neo Jia <c...@nvidia.com>
> ---
> hw/vfio/migration.c | 69
> +++++++++++++++++++++++++++++++++++++++++++
> hw/vfio/trace-events | 2 ++
> include/hw/vfio/vfio-common.h | 4 +++
> 3 files changed, 75 insertions(+)
>
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index c17bd1b0b934..28981a759e6c 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -10,6 +10,7 @@
> #include "qemu/osdep.h"
> #include <linux/vfio.h>
>
> +#include "sysemu/runstate.h"
> #include "hw/vfio/vfio-common.h"
> #include "cpu.h"
> #include "migration/migration.h"
> @@ -74,6 +75,67 @@ err:
> return ret;
> }
>
> +static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t set_flags,
> + uint32_t clear_flags)
> +{
Perhaps a mask and value interface like we have elsewhere?
> + VFIOMigration *migration = vbasedev->migration;
> + VFIORegion *region = &migration->region;
> + uint32_t device_state;
> + int ret = 0;
> +
> + /* same flags should not be set or clear */
> + assert(!(set_flags & clear_flags));
mask/value avoids this sort of thing.
> + device_state = (vbasedev->device_state | set_flags) & ~clear_flags;
Don't we need to re-read device_state from the region? We can't
predict what those reserved bits will be used for, they could be
volatile. If we adopt that a reset returns to running, our cached
state may be stale.
> +
> + switch (device_state & VFIO_DEVICE_STATE_MASK) {
> + case VFIO_DEVICE_STATE_INVALID_CASE1:
> + case VFIO_DEVICE_STATE_INVALID_CASE2:
> + return -EINVAL;
> + }
I like the VALID macro better.
> +
> + 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;
Are we opposed to re-reading device_state, here and in the error case
above?
> + 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 set_flags = 0, clear_flags = 0;
> +
> + if (running) {
> + set_flags = VFIO_DEVICE_STATE_RUNNING;
> + if (vbasedev->device_state & VFIO_DEVICE_STATE_RESUMING) {
> + clear_flags = VFIO_DEVICE_STATE_RESUMING;
> + }
> + } else {
> + clear_flags = VFIO_DEVICE_STATE_RUNNING;
> + }
> +
> + ret = vfio_migration_set_state(vbasedev, set_flags, clear_flags);
> + if (ret) {
> + error_report("%s: Failed to set device state 0x%x",
> + vbasedev->name, set_flags & ~clear_flags);
> + }
> + vbasedev->vm_running = running;
We're effectively storing running both in vbasedev->device_state and
vbasedev->vm_running, why?
Seems like this could trivially know the initial state of the device is
running.
> + trace_vfio_vmstate_change(vbasedev->name, running,
> RunState_str(state),
> + set_flags & ~clear_flags);
> + }
> +}
> +
> static int vfio_migration_init(VFIODevice *vbasedev,
> struct vfio_region_info *info)
> {
> @@ -89,6 +151,9 @@ static int vfio_migration_init(VFIODevice *vbasedev,
> return ret;
> }
>
> + vbasedev->vm_state =
> qemu_add_vm_change_state_handler(vfio_vmstate_change,
> + vbasedev);
> +
> return 0;
> }
>
> @@ -127,6 +192,10 @@ add_blocker:
>
> void vfio_migration_finalize(VFIODevice *vbasedev)
> {
> + 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);
> 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 927511897a44..6573acd6738e 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: "
>
> @@ -120,6 +121,9 @@ typedef struct VFIODevice {
> unsigned int flags;
> VFIOMigration *migration;
> Error *migration_blocker;
> + uint32_t device_state;
> + VMChangeStateEntry *vm_state;
> + int vm_running;
Isn't this effectively a bool per our usage.
Field ordering is wasteful.
> } VFIODevice;
>
> struct VFIODeviceOps {
