Re: [Qemu-block] [PATCH v3 1/1] virtio-scsi-ccw: use ioeventfd even when KVM is disabled

[Cornelia Huck]

On Tue,  4 Jul 2017 10:32:31 +0200
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 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.

It might be good to add a sentence that we don't have an equivalent to
"memory: emulate ioeventfd" for ccw yet, but that this doesn't hurt.

> 
> 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 
> ---
>  hw/s390x/virtio-ccw.c | 2 +-
>  target/s390x/cpu.h| 6 +-
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> 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/cpu.h b/target/s390x/cpu.h
> index 9faca04b52..bdb9bdbc9d 100644
> --- a/target/s390x/cpu.h
> +++ b/target/s390x/cpu.h
> @@ -1264,7 +1264,11 @@ 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;
> +}
>  }
>  
>  static inline void s390_crypto_reset(void)

Reviewed-by: Cornelia Huck 

Re: [Qemu-block] [PATCH v3 1/1] virtio-scsi-ccw: use ioeventfd even when KVM is disabled

[QingFeng Hao]

在 2017/7/4 17:34, Cornelia Huck 写道:

On Tue,  4 Jul 2017 10:32:31 +0200
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 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.

It might be good to add a sentence that we don't have an equivalent to
"memory: emulate ioeventfd" for ccw yet, but that this doesn't hurt.

Ok, I'll add it. thanks.



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 
---
  hw/s390x/virtio-ccw.c | 2 +-
  target/s390x/cpu.h| 6 +-
  2 files changed, 6 insertions(+), 2 deletions(-)

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/cpu.h b/target/s390x/cpu.h

index 9faca04b52..bdb9bdbc9d 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -1264,7 +1264,11 @@ 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;
+}
  }
  
  static inline void s390_crypto_reset(void)

Reviewed-by: Cornelia Huck 

Thanks!




--
Regards
QingFeng Hao

[Qemu-block] [PATCH v3 1/1] virtio-scsi-ccw: use ioeventfd even when KVM is disabled

[QingFeng Hao]

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 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 
---
 hw/s390x/virtio-ccw.c | 2 +-
 target/s390x/cpu.h| 6 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

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/cpu.h b/target/s390x/cpu.h
index 9faca04b52..bdb9bdbc9d 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -1264,7 +1264,11 @@ 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;
+}
 }
 
 static inline void s390_crypto_reset(void)
-- 
2.11.2