VFIO_DEVICE_FEATURE_LOW_POWER_ENTRY_WITH_WAKEUP correctly revokes DMABUFs on entry and, when paired with a VFIO_DEVICE_FEATURE_LOW_POWER_EXIT, vfio_pci_runtime_pm_exit() correctly un-revokes them.
However, when vfio_pci_core_runtime_resume() signals the eventfd on resume, the bare __vfio_pci_runtime_pm_exit() is used (which does not un-revoke). Add vfio_pci_dma_buf_move(false) to the resume path, making it similar to vfio_pci_runtime_pm_exit().
This also reorders the eventfd signal after the un-revoke and __vfio_pci_runtime_pm_exit() to guarantee that woken threads observe the new state.
Fixes: 5d74781ebc86 ("vfio/pci: Add dma-buf export support for MMIO regions") Signed-off-by: Matt Evans matt@ozlabs.org --- drivers/vfio/pci/vfio_pci_core.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 1f6066107831..e170cdc7ac92 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -527,8 +527,14 @@ static int vfio_pci_core_runtime_resume(struct device *dev) */ down_write(&vdev->memory_lock); if (vdev->pm_wake_eventfd_ctx) { - eventfd_signal(vdev->pm_wake_eventfd_ctx); + struct eventfd_ctx *ctx = vdev->pm_wake_eventfd_ctx; + + vdev->pm_wake_eventfd_ctx = NULL; __vfio_pci_runtime_pm_exit(vdev); + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, false); + eventfd_signal(ctx); + eventfd_ctx_put(ctx); } up_write(&vdev->memory_lock);