Re: [Qemu-block] [Qemu-devel] [PATCH 1/1] virtio-scsi-ccw: use ioeventfd even when KVM is disabled

[QingFeng Hao]

在 2017/7/3 19:48, Cornelia Huck 写道:

On Mon,  3 Jul 2017 09:38:36 +0200
QingFeng Hao  wrote:


Do not check kvm_eventfds_enabled() when KVM is disabled since it
always returns 0.  Since commit
8c56c1a592b5092d91da8d8943c1d6462a6f ("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 
Signed-off-by: Stefan Hajnoczi 
---
  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;
+}

I'd prefer if you moved the kvm_enabled() check into
s390_assign_subch_ioeventfd().

Thanks and I'll change it just as Christian's comment.



  if (!kvm_check_extension(kvm_state, KVM_CAP_IOEVENTFD)) {
  return -ENOSYS;
  }


--
Regards
QingFeng Hao

Re: [Qemu-block] [Qemu-devel] [PATCH 1/1] virtio-scsi-ccw: use ioeventfd even when KVM is disabled

[Cornelia Huck]

On Mon,  3 Jul 2017 09:38:36 +0200
QingFeng Hao  wrote:

> Do not check kvm_eventfds_enabled() when KVM is disabled since it
> always returns 0.  Since commit
> 8c56c1a592b5092d91da8d8943c1d6462a6f ("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 
> Signed-off-by: Stefan Hajnoczi 
> ---
>  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;
> +}

I'd prefer if you moved the kvm_enabled() check into
s390_assign_subch_ioeventfd().

>  if (!kvm_check_extension(kvm_state, KVM_CAP_IOEVENTFD)) {
>  return -ENOSYS;
>  }