[v1] Ensure full early console access with libvirt

[RFC PATCH libvirt v1 0/3] Ensure full early console access with libvirt

Marc Hartmayer posted 3 patches 7 months ago

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git fetch https://github.com/patchew-project/libvirt tags/patchew/20230925133910.77945-1-mhartmay@linux.ibm.com

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tools/virsh-console.c |  8 ++++++++
tools/virsh-console.h |  1 +
tools/virsh-domain.c  | 32 ++++++++++++++++++++++++++------
3 files changed, 35 insertions(+), 6 deletions(-)

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[RFC PATCH libvirt v1 0/3] Ensure full early console access with libvirt

Posted by Marc Hartmayer 7 months ago

Currently, early console output may be lost, e.g. if starting a guest with
`virsh start --console` guest, which can make debugging of early failures very
difficult
(like zipl messages or disabled wait conditions happening early). This is
because QEMU may emit serial console output before the libvirt console client
starts to consume data from the pts. This can be prevented by starting the guest
in paused state, connect to the console and then resume the guest.

Note: There is still a problem in QEMU itself, see QEMU patch series `[PATCH]
chardev/char-pty: Avoid losing bytes when the other side just (re-)connected`
[1]

[1] https://lists.gnu.org/archive/html/qemu-devel/2023-08/msg02725.html

Marc Hartmayer (3):
  virsh: add `console --resume` support
  Improve `virsh start --console` behavior
  Improve `virsh create --console` behavior

 tools/virsh-console.c |  8 ++++++++
 tools/virsh-console.h |  1 +
 tools/virsh-domain.c  | 32 ++++++++++++++++++++++++++------
 3 files changed, 35 insertions(+), 6 deletions(-)


base-commit: 3fd64fb0e236fc80ffa2cc977c0d471f11fc39bf
-- 
2.34.1