virtio-blk.c (0cd09c3a6cc2230ba38c462fc410b4acce59eb6f) virtio-blk.c (ef546f1275f6563e8934dd5e338d29d9f9909ca6)
1/*
2 * Virtio Block Device
3 *
4 * Copyright IBM, Corp. 2007
5 *
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
8 *

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728 }
729
730 return features;
731}
732
733static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
734{
735 VirtIOBlock *s = VIRTIO_BLK(vdev);
1/*
2 * Virtio Block Device
3 *
4 * Copyright IBM, Corp. 2007
5 *
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
8 *

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728 }
729
730 return features;
731}
732
733static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
734{
735 VirtIOBlock *s = VIRTIO_BLK(vdev);
736 uint32_t features;
737
738 if (s->dataplane && !(status & (VIRTIO_CONFIG_S_DRIVER |
739 VIRTIO_CONFIG_S_DRIVER_OK))) {
740 virtio_blk_data_plane_stop(s->dataplane);
741 }
742
743 if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
744 return;
745 }
746
736
737 if (s->dataplane && !(status & (VIRTIO_CONFIG_S_DRIVER |
738 VIRTIO_CONFIG_S_DRIVER_OK))) {
739 virtio_blk_data_plane_stop(s->dataplane);
740 }
741
742 if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
743 return;
744 }
745
747 features = vdev->guest_features;
748
749 /* A guest that supports VIRTIO_BLK_F_CONFIG_WCE must be able to send
750 * cache flushes. Thus, the "auto writethrough" behavior is never
751 * necessary for guests that support the VIRTIO_BLK_F_CONFIG_WCE feature.
752 * Leaving it enabled would break the following sequence:
753 *
754 * Guest started with "-drive cache=writethrough"
755 * Guest sets status to 0
756 * Guest sets DRIVER bit in status field
757 * Guest reads host features (WCE=0, CONFIG_WCE=1)
758 * Guest writes guest features (WCE=0, CONFIG_WCE=1)
759 * Guest writes 1 to the WCE configuration field (writeback mode)
760 * Guest sets DRIVER_OK bit in status field
761 *
762 * s->blk would erroneously be placed in writethrough mode.
763 */
746 /* A guest that supports VIRTIO_BLK_F_CONFIG_WCE must be able to send
747 * cache flushes. Thus, the "auto writethrough" behavior is never
748 * necessary for guests that support the VIRTIO_BLK_F_CONFIG_WCE feature.
749 * Leaving it enabled would break the following sequence:
750 *
751 * Guest started with "-drive cache=writethrough"
752 * Guest sets status to 0
753 * Guest sets DRIVER bit in status field
754 * Guest reads host features (WCE=0, CONFIG_WCE=1)
755 * Guest writes guest features (WCE=0, CONFIG_WCE=1)
756 * Guest writes 1 to the WCE configuration field (writeback mode)
757 * Guest sets DRIVER_OK bit in status field
758 *
759 * s->blk would erroneously be placed in writethrough mode.
760 */
764 if (!(features & (1 << VIRTIO_BLK_F_CONFIG_WCE))) {
761 if (!virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) {
765 aio_context_acquire(blk_get_aio_context(s->blk));
766 blk_set_enable_write_cache(s->blk,
762 aio_context_acquire(blk_get_aio_context(s->blk));
763 blk_set_enable_write_cache(s->blk,
767 !!(features & (1 << VIRTIO_BLK_F_WCE)));
764 virtio_has_feature(vdev, VIRTIO_BLK_F_WCE));
768 aio_context_release(blk_get_aio_context(s->blk));
769 }
770}
771
772static void virtio_blk_save(QEMUFile *f, void *opaque)
773{
774 VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
775

--- 215 unchanged lines hidden --- 		765 aio_context_release(blk_get_aio_context(s->blk));
766 }
767}
768
769static void virtio_blk_save(QEMUFile *f, void *opaque)
770{
771 VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
772

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