diff options
| author | Laszlo Ersek <lersek@redhat.com> | 2016-02-18 20:31:00 +0100 |
|---|---|---|
| committer | Gerd Hoffmann <kraxel@redhat.com> | 2016-02-26 10:06:40 +0100 |
| commit | e6915b5f3a874a467a9a65f7ec1d6ef8d251a51a (patch) | |
| tree | 571a711b449bf556e5b1529be77e17a5432b37c9 /include | |
| parent | 0c6940d086f39bbf725d96104abe46da87429cb6 (diff) | |
fw_cfg: unbreak migration compatibility for 2.4 and earlier machines
When I reviewed Marc's fw_cfg DMA patches, I completely missed that the
way we set dma_enabled would break migration.
Gerd explained the right way (see reference below): dma_enabled should be
set to true by default, and only true->false transitions should be
possible:
- when the user requests that with
-global fw_cfg_mem.dma_enabled=off
or
-global fw_cfg_io.dma_enabled=off
as appropriate for the platform,
- when HW_COMPAT_2_4 dictates it,
- when board code initializes fw_cfg without requesting DMA support.
Cc: Marc Marí <markmb@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Alexandre DERUMIER <aderumier@odiso.com>
Cc: qemu-stable@nongnu.org
Ref: http://thread.gmane.org/gmane.comp.emulators.qemu/390272/focus=391042
Ref: https://bugs.launchpad.net/qemu/+bug/1536487
Suggested-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1455823860-22268-1-git-send-email-lersek@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/hw/compat.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/include/hw/compat.h b/include/hw/compat.h index 2ebe739fcb..a5dbbf8984 100644 --- a/include/hw/compat.h +++ b/include/hw/compat.h @@ -42,6 +42,14 @@ .driver = "virtio-pci",\ .property = "migrate-extra",\ .value = "off",\ + },{\ + .driver = "fw_cfg_mem",\ + .property = "dma_enabled",\ + .value = "off",\ + },{\ + .driver = "fw_cfg_io",\ + .property = "dma_enabled",\ + .value = "off",\ }, #define HW_COMPAT_2_3 \ |