Virtualization
/
SLOF
mirror of https://gitlab.com/qemu-project/SLOF.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

virtio-serial: Rework shutdown sequence 

The "io" word of term-io.fs opens two separate instances of the device
for stdin and stdout. The prom_init() function in Linux closes stdin at
some point, which internally calls quiesce and shuts the device down
through a quiesce hook.

When the "open-count" variable in virtio-serial.fs reaches 0, ie. when
closing the last instance, we call "close" two times, which is clearly
wrong. This never hits however because the stdout instance is never
closed which prevents "open-count" to reach 0.

It would make more sense to shutdown the device when closing the last
instance, for symmetry with the first open that initializes the device.
Change the shutdown sequence to do that rather than relying on a quiesce
hook.

Have quiesce to explicitly close stdout, which is supposedly the last
instance, and shutdown the device.

Signed-off-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
This commit is contained in:
Greg Kurz 2020-03-09 23:43:12 +01:00 committed by Alexey Kardashevskiy
parent 1641d2d5eb
commit cf28264196
2 changed files with 8 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
board-qemu/slof/virtio-serial.fs
View File

@ -19,13 +19,8 @@ virtio-setup-vd VALUE virtiodev
\ Quiescence the virtqueue of this device so that no more background
\ transactions can be pending.
: shutdown ( -- )
initialized? IF
my-phandle node>path open-dev ?dup IF
virtiodev virtio-serial-shutdown
close-dev
THEN
FALSE to initialized?
THEN
virtiodev virtio-serial-shutdown
FALSE to initialized?
;
: virtio-serial-term-emit
@ -39,7 +34,6 @@ virtio-setup-vd VALUE virtiodev
: init ( -- )
virtiodev virtio-serial-init drop
TRUE to initialized?
['] shutdown add-quiesce-xt
;
0 VALUE open-count
@ -58,7 +52,7 @@ virtiodev virtio-serial-init drop
: close
open-count 0> IF
open-count 1 - dup to open-count
0= IF close THEN
0= IF shutdown THEN
THEN
close
;

5
slof/fs/client.fs
View File

@ -203,6 +203,11 @@ ALSO client-voc DEFINITIONS
\ End of life of SLOF now, call platform quiesce as quiesce
\ is an undocumented extension and not everybody supports it
close-dev
\ Some device, eg. virtio-serial, need all instances to be
\ closed in order to be reset properly
s" stdout" get-chosen IF
decode-int nip nip close-dev
THEN
quiesce
ELSE
close-dev