On 07/04/2017 05:41 AM, QingFeng Hao wrote: > > > 在 2017/7/3 18:20, Christian Borntraeger 写道: >> On 07/03/2017 10:51 AM, QingFeng Hao wrote: >>> This patch is based on a similar patch from Stefan Hajnoczi - >>> commit c324fd0a39c (" virtio-pci: use ioeventfd even when KVM is disabled) >>> >>> Do not check kvm_eventfds_enabled() when KVM is disabled since it >>> always returns 0. Since commit 8c56c1a592b5092d91da8d8943c17777d6462a6f >>> ("memory: emulate ioeventfd") it has been possible to use ioeventfds in >>> qtest or TCG mode. >>> >>> This patch makes -device virtio-scsi-ccw,iothread=iothread0 work even >>> when KVM is disabled. >>> >>> I have tested that virtio-scsi-ccw works under tcg both with and without >>> iothread. >>> >>> This patch fixes qemu-iotests 068, which was accidentally merged early >>> despite the dependency on ioeventfd. >>> >>> Signed-off-by: QingFeng Hao <ha...@linux.vnet.ibm.com> >>> --- >>> hw/s390x/virtio-ccw.c | 2 +- >>> target/s390x/kvm.c | 3 +++ >>> 2 files changed, 4 insertions(+), 1 deletion(-) >>> >>> diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c >>> index 90d37cb9ff..35896eb007 100644 >>> --- a/hw/s390x/virtio-ccw.c >>> +++ b/hw/s390x/virtio-ccw.c >>> @@ -711,7 +711,7 @@ static void virtio_ccw_device_realize(VirtioCcwDevice >>> *dev, Error **errp) >>> sch->cssid, sch->ssid, sch->schid, sch->devno, >>> ccw_dev->devno.valid ? "user-configured" : "auto-configured"); >>> >>> - if (!kvm_eventfds_enabled()) { >>> + if (kvm_enabled() && !kvm_eventfds_enabled()) { >>> dev->flags &= ~VIRTIO_CCW_FLAG_USE_IOEVENTFD; >>> } >>> >>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c >>> index a3d00196f4..c37f9c3b9e 100644 >>> --- a/target/s390x/kvm.c >>> +++ b/target/s390x/kvm.c >>> @@ -2220,6 +2220,9 @@ int kvm_s390_assign_subch_ioeventfd(EventNotifier >>> *notifier, uint32_t sch, >>> .addr = sch, >>> .len = 8, >>> }; >>> + if (!kvm_enabled()) { >>> + return 0; >>> + } >> thinking more about it. wouldnt it be better to do something like this >> instead >> >> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h >> index 058ddad..cc47831 100644 >> --- a/target/s390x/cpu.h >> +++ b/target/s390x/cpu.h >> @@ -1240,7 +1240,11 @@ static inline int >> s390_assign_subch_ioeventfd(EventNotifier *notifier, >> uint32_t sch_id, int vq, >> bool assign) >> { >> - return kvm_s390_assign_subch_ioeventfd(notifier, sch_id, vq, assign); >> + if (kvm_enabled()) { >> + return kvm_s390_assign_subch_ioeventfd(notifier, sch_id, vq, >> assign); >> + } else { >> + return 0; >> + } >> } > Thanks. It makes sense. I'll change it. >> static inline void s390_crypto_reset(void) >> >> >> FWIW, it seems that we (s390) do not have a functional equivalent function >> as commit >> 8c56c1a592b5092d91da8d8943c17777d6462a6f ("memory: emulate ioeventfd") , so >> we will >> not use the iothreads. > Ok, but might s390 have skipped the iothread arguments and passed the test, > so we could > still keep this test case?
Yes, lets just fix the test case. We can implement emulated ioeventfds later.