Am 08.11.21 um 13:48 schrieb Janosch Frank:
On 11/8/21 13:04, Christian Borntraeger wrote:
Am 08.11.21 um 12:12 schrieb Janosch Frank:
On 10/27/21 04:54, Collin Walling wrote:
The diag 318 data contains values that denote information regarding the
guest's environment. Currently, it is unecessarily difficult to observe
this value (either manually-inserted debug statements, gdb stepping, mem
dumping etc). It's useful to observe this information to obtain an
at-a-glance view of the guest's environment, so lets add a simple VCPU
event that prints the CPNC to the s390dbf logs.
Signed-off-by: Collin Walling <walling@xxxxxxxxxxxxx>
---
arch/s390/kvm/kvm-s390.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 6a6dd5e1daf6..da3ff24eabd0 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4254,6 +4254,7 @@ static void sync_regs_fmt2(struct kvm_vcpu *vcpu)
if (kvm_run->kvm_dirty_regs & KVM_SYNC_DIAG318) {
vcpu->arch.diag318_info.val = kvm_run->s.regs.diag318;
vcpu->arch.sie_block->cpnc = vcpu->arch.diag318_info.cpnc;
+ VCPU_EVENT(vcpu, 2, "setting cpnc to %d", vcpu->arch.diag318_info.cpnc);
}
/*
* If userspace sets the riccb (e.g. after migration) to a valid state,
Won't that turn up for every vcpu and spam the log?
only if the userspace always sets the dirty bit (which it should not).
But that's exactly what it does, no?
We do a loop over all vcpus and call kvm_s390_set_diag318() which sets the info in kvm_run and sets the diag318 bit in the kvm_dirty_regs.
Yes, ONCE per CPU. And this is exactly what I want to see. (and it did show a bug in qemu that we only set it for one cpu to the correct value).
@Collin: Could you check that please?
