diff options
| author | Laszlo Ersek <lersek@redhat.com> | 2016-02-18 20:31:00 +0100 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2016-03-17 17:33:59 -0500 |
| commit | 30929793b0a68c1f7ef85035bc0159a835e7a0cb (patch) | |
| tree | 94abb2ebbf1fdf7bcfd287f57af532b443abfbbc /include | |
| parent | c5c9841ce8acd2ce836a729783cc37984baeab69 (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>
(cherry picked from commit e6915b5f3a874a467a9a65f7ec1d6ef8d251a51a)
Conflicts:
include/hw/compat.h
* remove cosmetic dep on c9c0afbb
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.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 d0b1c4f1ef..b7973db5e2 100644 --- a/include/hw/compat.h +++ b/include/hw/compat.h @@ -18,6 +18,14 @@ .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 \ |