[v15,6/6] KVM: s390: pv: module parameter to fence asynchronous destroy

Commit Message

Claudio Imbrenda Oct. 10, 2022, 2:54 p.m. UTC

Add the module parameter "async_destroy", to allow the asynchronous
destroy mechanism to be switched off. This might be useful for
debugging purposes.

The parameter is enabled by default since the feature is opt-in anyway.

Signed-off-by: Claudio Imbrenda <[e-mail]>
Reviewed-by: Janosch Frank <[e-mail]>
Reviewed-by: Steffen Eiden <[e-mail]>
---
 arch/s390/kvm/kvm-s390.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Comments

Nico Boehr Oct. 12, 2022, 8:51 a.m. UTC | #1

Quoting Claudio Imbrenda (2022-10-10 16:54:42)
> Add the module parameter "async_destroy", to allow the asynchronous
> destroy mechanism to be switched off. This might be useful for
> debugging purposes.
> 
> The parameter is enabled by default since the feature is opt-in anyway.
> 
> Signed-off-by: Claudio Imbrenda <[e-mail]>
> Reviewed-by: Janosch Frank <[e-mail]>
> Reviewed-by: Steffen Eiden <[e-mail]>

I seem to have forgotten to give my:

Reviewed-by: Nico Boehr <[e-mail]>

Patch

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 372230b92448..c75754215c8e 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -209,7 +209,13 @@  unsigned int diag9c_forwarding_hz;
 module_param(diag9c_forwarding_hz, uint, 0644);
 MODULE_PARM_DESC(diag9c_forwarding_hz, "Maximum diag9c forwarding per second, 0 to turn off");
 
-static int async_destroy;
+/*
+ * allow asynchronous deinit for protected guests; enable by default since
+ * the feature is opt-in anyway
+ */
+static int async_destroy = 1;
+module_param(async_destroy, int, 0444);
+MODULE_PARM_DESC(async_destroy, "Asynchronous destroy for protected guests");
 
 /*
  * For now we handle at most 16 double words as this is what the s390 base