summaryrefslogtreecommitdiff
path: root/drivers/video
diff options
context:
space:
mode:
authorGuilherme G. Piccoli <gpiccoli@igalia.com>2022-08-20 01:17:30 +0300
committerWei Liu <wei.liu@kernel.org>2022-11-28 19:48:20 +0300
commitd786e00d19f9fc80c2239a07643b08ea75b8b364 (patch)
treeec7965a6d1480218343308ae181496a4bfa95a66 /drivers/video
parent1d044ca035dc22df0d3b39e56f2881071d9118bd (diff)
downloadlinux-d786e00d19f9fc80c2239a07643b08ea75b8b364.tar.xz
drivers: hv, hyperv_fb: Untangle and refactor Hyper-V panic notifiers
Currently Hyper-V guests are among the most relevant users of the panic infrastructure, like panic notifiers, kmsg dumpers, etc. The reasons rely both in cleaning-up procedures (closing hypervisor <-> guest connection, disabling some paravirtualized timer) as well as to data collection (sending panic information to the hypervisor) and framebuffer management. The thing is: some notifiers are related to others, ordering matters, some functionalities are duplicated and there are lots of conditionals behind sending panic information to the hypervisor. As part of an effort to clean-up the panic notifiers mechanism and better document things, we hereby address some of the issues/complexities of Hyper-V panic handling through the following changes: (a) We have die and panic notifiers on vmbus_drv.c and both have goals of sending panic information to the hypervisor, though the panic notifier is also responsible for a cleaning-up procedure. This commit clears the code by splitting the panic notifier in two, one for closing the vmbus connection whereas the other is only for sending panic info to hypervisor. With that, it was possible to merge the die and panic notifiers in a single/well-documented function, and clear some conditional complexities on sending such information to the hypervisor. (b) There is a Hyper-V framebuffer panic notifier, which relies in doing a vmbus operation that demands a valid connection. So, we must order this notifier with the panic notifier from vmbus_drv.c, to guarantee that the framebuffer code executes before the vmbus connection is unloaded. Also, this commit removes a useless header. Although there is code rework and re-ordering, we expect that this change has no functional regressions but instead optimize the path and increase panic reliability on Hyper-V. This was tested on Hyper-V with success. Cc: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Cc: Dexuan Cui <decui@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Tianyu Lan <Tianyu.Lan@microsoft.com> Cc: Wei Liu <wei.liu@kernel.org> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Tested-by: Fabio A M Martins <fabiomirmar@gmail.com> Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Tested-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20220819221731.480795-11-gpiccoli@igalia.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/fbdev/hyperv_fb.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index 4ff25dfc865d..3ce746a46179 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -1214,7 +1214,15 @@ static int hvfb_probe(struct hv_device *hdev,
par->fb_ready = true;
par->synchronous_fb = false;
+
+ /*
+ * We need to be sure this panic notifier runs _before_ the
+ * vmbus disconnect, so order it by priority. It must execute
+ * before the function hv_panic_vmbus_unload() [drivers/hv/vmbus_drv.c],
+ * which is almost at the end of list, with priority = INT_MIN + 1.
+ */
par->hvfb_panic_nb.notifier_call = hvfb_on_panic;
+ par->hvfb_panic_nb.priority = INT_MIN + 10,
atomic_notifier_chain_register(&panic_notifier_list,
&par->hvfb_panic_nb);