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| author | Pierre Morel <pmorel@linux.ibm.com> | 2020-09-07 15:26:07 +0200 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2021-03-09 10:16:26 +0100 |
| commit | 87e28a15c42cc592009c32a8c20e5789059027c2 (patch) | |
| tree | d1fecf787809e547737239ce637072fcca473c18 /arch/s390/kvm/kvm-s390.c | |
| parent | 38860756a19042c2159178f57ec6e147b13ddfc2 (diff) | |
| download | linux-87e28a15c42cc592009c32a8c20e5789059027c2.tar.gz linux-87e28a15c42cc592009c32a8c20e5789059027c2.tar.bz2 linux-87e28a15c42cc592009c32a8c20e5789059027c2.zip | |
KVM: s390: diag9c (directed yield) forwarding
When we intercept a DIAG_9C from the guest we verify that the
target real CPU associated with the virtual CPU designated by
the guest is running and if not we forward the DIAG_9C to the
target real CPU.
To avoid a diag9c storm we allow a maximal rate of diag9c forwarding.
The rate is calculated as a count per second defined as a new
parameter of the s390 kvm module: diag9c_forwarding_hz .
The default value of 0 is to not forward diag9c.
Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Link: https://lore.kernel.org/r/1613997661-22525-2-git-send-email-pmorel@linux.ibm.com
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/kvm/kvm-s390.c')
| -rw-r--r-- | arch/s390/kvm/kvm-s390.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 333193982e51..cfe720d16a6a 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -158,6 +158,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { VCPU_STAT("instruction_diag_44", diagnose_44), VCPU_STAT("instruction_diag_9c", diagnose_9c), VCPU_STAT("diag_9c_ignored", diagnose_9c_ignored), + VCPU_STAT("diag_9c_forward", diagnose_9c_forward), VCPU_STAT("instruction_diag_258", diagnose_258), VCPU_STAT("instruction_diag_308", diagnose_308), VCPU_STAT("instruction_diag_500", diagnose_500), @@ -185,6 +186,11 @@ static bool use_gisa = true; module_param(use_gisa, bool, 0644); MODULE_PARM_DESC(use_gisa, "Use the GISA if the host supports it."); +/* maximum diag9c forwarding per second */ +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"); + /* * For now we handle at most 16 double words as this is what the s390 base * kernel handles and stores in the prefix page. If we ever need to go beyond |