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| author | Eric Farman <farman@linux.ibm.com> | 2021-12-14 00:05:50 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-01-20 11:13:14 +0300 |
| commit | 252435941c3399173a5f2d3d35b01fed9ce2dd8f (patch) | |
| tree | a056f05a4b7b12c8d70b8e048492ba600847e8e9 /arch/s390/kvm/kvm-s390.c | |
| parent | 6e8b6dcec07ccd81656578a42a64f44929c386cd (diff) | |
| download | linux-252435941c3399173a5f2d3d35b01fed9ce2dd8f.tar.xz | |
KVM: s390: Clarify SIGP orders versus STOP/RESTART
commit 812de04661c4daa7ac385c0dfd62594540538034 upstream.
With KVM_CAP_S390_USER_SIGP, there are only five Signal Processor
orders (CONDITIONAL EMERGENCY SIGNAL, EMERGENCY SIGNAL, EXTERNAL CALL,
SENSE, and SENSE RUNNING STATUS) which are intended for frequent use
and thus are processed in-kernel. The remainder are sent to userspace
with the KVM_CAP_S390_USER_SIGP capability. Of those, three orders
(RESTART, STOP, and STOP AND STORE STATUS) have the potential to
inject work back into the kernel, and thus are asynchronous.
Let's look for those pending IRQs when processing one of the in-kernel
SIGP orders, and return BUSY (CC2) if one is in process. This is in
agreement with the Principles of Operation, which states that only one
order can be "active" on a CPU at a time.
Cc: stable@vger.kernel.org
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20211213210550.856213-2-farman@linux.ibm.com
[borntraeger@linux.ibm.com: add stable tag]
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/s390/kvm/kvm-s390.c')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 1c97493d21e1..24e42bd7d3b7 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -4642,10 +4642,15 @@ int kvm_s390_vcpu_stop(struct kvm_vcpu *vcpu) } } - /* SIGP STOP and SIGP STOP AND STORE STATUS has been fully processed */ + /* + * Set the VCPU to STOPPED and THEN clear the interrupt flag, + * now that the SIGP STOP and SIGP STOP AND STORE STATUS orders + * have been fully processed. This will ensure that the VCPU + * is kept BUSY if another VCPU is inquiring with SIGP SENSE. + */ + kvm_s390_set_cpuflags(vcpu, CPUSTAT_STOPPED); kvm_s390_clear_stop_irq(vcpu); - kvm_s390_set_cpuflags(vcpu, CPUSTAT_STOPPED); __disable_ibs_on_vcpu(vcpu); for (i = 0; i < online_vcpus; i++) { |