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authorHalil Pasic <pasic@linux.ibm.com>2021-10-19 19:53:59 +0200
committerChristian Borntraeger <borntraeger@de.ibm.com>2021-10-20 13:03:04 +0200
commit9b57e9d5010bbed7c0d9d445085840f7025e6f9a (patch)
tree3665218fb6d52805e8ee62da349cac0169cd0e5c /arch/s390/kvm
parent25b5476a294cd5f7c7730f334f6b400d30bb783d (diff)
downloadlinux-9b57e9d5010bbed7c0d9d445085840f7025e6f9a.tar.bz2
KVM: s390: clear kicked_mask before sleeping again
The idea behind kicked mask is that we should not re-kick a vcpu that is already in the "kick" process, i.e. that was kicked and is is about to be dispatched if certain conditions are met. The problem with the current implementation is, that it assumes the kicked vcpu is going to enter SIE shortly. But under certain circumstances, the vcpu we just kicked will be deemed non-runnable and will remain in wait state. This can happen, if the interrupt(s) this vcpu got kicked to deal with got already cleared (because the interrupts got delivered to another vcpu). In this case kvm_arch_vcpu_runnable() would return false, and the vcpu would remain in kvm_vcpu_block(), but this time with its kicked_mask bit set. So next time around we wouldn't kick the vcpu form __airqs_kick_single_vcpu(), but would assume that we just kicked it. Let us make sure the kicked_mask is cleared before we give up on re-dispatching the vcpu. Fixes: 9f30f6216378 ("KVM: s390: add gib_alert_irq_handler()") Reported-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Halil Pasic <pasic@linux.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Michael Mueller <mimu@linux.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Link: https://lore.kernel.org/r/20211019175401.3757927-2-pasic@linux.ibm.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/kvm')
-rw-r--r--arch/s390/kvm/kvm-s390.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 6a6dd5e1daf6..1c97493d21e1 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -3363,6 +3363,7 @@ out_free_sie_block:
int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
{
+ clear_bit(vcpu->vcpu_idx, vcpu->kvm->arch.gisa_int.kicked_mask);
return kvm_s390_vcpu_has_irq(vcpu, 0);
}