* [Qemu-devel] [PATCH] virtio/vhost: drop unnecessary VHOST_SET_VRING call
@ 2015-08-12 10:19 Marcel Apfelbaum
2015-08-12 10:34 ` Michael S. Tsirkin
0 siblings, 1 reply; 4+ messages in thread
From: Marcel Apfelbaum @ 2015-08-12 10:19 UTC (permalink / raw)
To: qemu-devel; +Cc: marcel, mst
No need to send VHOST_SET_VRING_CALL to backend
before the negotiation with the guest is finished.
Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
---
hw/virtio/vhost.c | 13 +------------
1 file changed, 1 insertion(+), 12 deletions(-)
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 2712c6f..b448542 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -875,24 +875,13 @@ static void vhost_eventfd_del(MemoryListener *listener,
static int vhost_virtqueue_init(struct vhost_dev *dev,
struct vhost_virtqueue *vq, int n)
{
- struct vhost_vring_file file = {
- .index = n,
- };
int r = event_notifier_init(&vq->masked_notifier, 0);
+
if (r < 0) {
return r;
}
- file.fd = event_notifier_get_fd(&vq->masked_notifier);
- r = dev->vhost_ops->vhost_call(dev, VHOST_SET_VRING_CALL, &file);
- if (r) {
- r = -errno;
- goto fail_call;
- }
return 0;
-fail_call:
- event_notifier_cleanup(&vq->masked_notifier);
- return r;
}
static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
--
2.1.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH] virtio/vhost: drop unnecessary VHOST_SET_VRING call
2015-08-12 10:19 [Qemu-devel] [PATCH] virtio/vhost: drop unnecessary VHOST_SET_VRING call Marcel Apfelbaum
@ 2015-08-12 10:34 ` Michael S. Tsirkin
2015-08-12 11:10 ` Marcel Apfelbaum
0 siblings, 1 reply; 4+ messages in thread
From: Michael S. Tsirkin @ 2015-08-12 10:34 UTC (permalink / raw)
To: Marcel Apfelbaum; +Cc: qemu-devel
On Wed, Aug 12, 2015 at 01:19:51PM +0300, Marcel Apfelbaum wrote:
> No need to send VHOST_SET_VRING_CALL to backend
> before the negotiation with the guest is finished.
>
> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
Well - we do need to set it to the masked notifier initially to avoid
losing events. You can't just drop it - need to move this call
somewhere else.
> ---
> hw/virtio/vhost.c | 13 +------------
> 1 file changed, 1 insertion(+), 12 deletions(-)
>
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index 2712c6f..b448542 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -875,24 +875,13 @@ static void vhost_eventfd_del(MemoryListener *listener,
> static int vhost_virtqueue_init(struct vhost_dev *dev,
> struct vhost_virtqueue *vq, int n)
> {
> - struct vhost_vring_file file = {
> - .index = n,
> - };
> int r = event_notifier_init(&vq->masked_notifier, 0);
> +
> if (r < 0) {
> return r;
> }
>
> - file.fd = event_notifier_get_fd(&vq->masked_notifier);
> - r = dev->vhost_ops->vhost_call(dev, VHOST_SET_VRING_CALL, &file);
> - if (r) {
> - r = -errno;
> - goto fail_call;
> - }
> return 0;
> -fail_call:
> - event_notifier_cleanup(&vq->masked_notifier);
> - return r;
> }
>
> static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
> --
> 2.1.0
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH] virtio/vhost: drop unnecessary VHOST_SET_VRING call
2015-08-12 10:34 ` Michael S. Tsirkin
@ 2015-08-12 11:10 ` Marcel Apfelbaum
2015-08-12 11:15 ` Michael S. Tsirkin
0 siblings, 1 reply; 4+ messages in thread
From: Marcel Apfelbaum @ 2015-08-12 11:10 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: qemu-devel
On 08/12/2015 01:34 PM, Michael S. Tsirkin wrote:
> On Wed, Aug 12, 2015 at 01:19:51PM +0300, Marcel Apfelbaum wrote:
>> No need to send VHOST_SET_VRING_CALL to backend
>> before the negotiation with the guest is finished.
>>
>> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
>
> Well - we do need to set it to the masked notifier initially to avoid
> losing events. You can't just drop it - need to move this call
> somewhere else.
What do we need to set?
I just dropped the call to VHOST_SET_VRING_CALL.
Thanks,
Marcel
>
>> ---
>> hw/virtio/vhost.c | 13 +------------
>> 1 file changed, 1 insertion(+), 12 deletions(-)
>>
>> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
>> index 2712c6f..b448542 100644
>> --- a/hw/virtio/vhost.c
>> +++ b/hw/virtio/vhost.c
>> @@ -875,24 +875,13 @@ static void vhost_eventfd_del(MemoryListener *listener,
>> static int vhost_virtqueue_init(struct vhost_dev *dev,
>> struct vhost_virtqueue *vq, int n)
>> {
>> - struct vhost_vring_file file = {
>> - .index = n,
>> - };
>> int r = event_notifier_init(&vq->masked_notifier, 0);
>> +
>> if (r < 0) {
>> return r;
>> }
>>
>> - file.fd = event_notifier_get_fd(&vq->masked_notifier);
>> - r = dev->vhost_ops->vhost_call(dev, VHOST_SET_VRING_CALL, &file);
>> - if (r) {
>> - r = -errno;
>> - goto fail_call;
>> - }
>> return 0;
>> -fail_call:
>> - event_notifier_cleanup(&vq->masked_notifier);
>> - return r;
>> }
>>
>> static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
>> --
>> 2.1.0
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH] virtio/vhost: drop unnecessary VHOST_SET_VRING call
2015-08-12 11:10 ` Marcel Apfelbaum
@ 2015-08-12 11:15 ` Michael S. Tsirkin
0 siblings, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2015-08-12 11:15 UTC (permalink / raw)
To: Marcel Apfelbaum; +Cc: qemu-devel
On Wed, Aug 12, 2015 at 02:10:56PM +0300, Marcel Apfelbaum wrote:
> On 08/12/2015 01:34 PM, Michael S. Tsirkin wrote:
> >On Wed, Aug 12, 2015 at 01:19:51PM +0300, Marcel Apfelbaum wrote:
> >>No need to send VHOST_SET_VRING_CALL to backend
> >>before the negotiation with the guest is finished.
> >>
> >>Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
> >
> >Well - we do need to set it to the masked notifier initially to avoid
> >losing events. You can't just drop it - need to move this call
> >somewhere else.
> What do we need to set?
> I just dropped the call to VHOST_SET_VRING_CALL.
>
> Thanks,
> Marcel
We use two eventfds: masked and unmasked one.
We switch dynamically dependent on msi mask value.
Code assumes we start out masked, so we need to match that.
> >
> >>---
> >> hw/virtio/vhost.c | 13 +------------
> >> 1 file changed, 1 insertion(+), 12 deletions(-)
> >>
> >>diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> >>index 2712c6f..b448542 100644
> >>--- a/hw/virtio/vhost.c
> >>+++ b/hw/virtio/vhost.c
> >>@@ -875,24 +875,13 @@ static void vhost_eventfd_del(MemoryListener *listener,
> >> static int vhost_virtqueue_init(struct vhost_dev *dev,
> >> struct vhost_virtqueue *vq, int n)
> >> {
> >>- struct vhost_vring_file file = {
> >>- .index = n,
> >>- };
> >> int r = event_notifier_init(&vq->masked_notifier, 0);
> >>+
> >> if (r < 0) {
> >> return r;
> >> }
> >>
> >>- file.fd = event_notifier_get_fd(&vq->masked_notifier);
> >>- r = dev->vhost_ops->vhost_call(dev, VHOST_SET_VRING_CALL, &file);
> >>- if (r) {
> >>- r = -errno;
> >>- goto fail_call;
> >>- }
> >> return 0;
> >>-fail_call:
> >>- event_notifier_cleanup(&vq->masked_notifier);
> >>- return r;
> >> }
> >>
> >> static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
> >>--
> >>2.1.0
^ permalink raw reply [flat|nested] 4+ messages in thread
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2015-08-12 10:19 [Qemu-devel] [PATCH] virtio/vhost: drop unnecessary VHOST_SET_VRING call Marcel Apfelbaum
2015-08-12 10:34 ` Michael S. Tsirkin
2015-08-12 11:10 ` Marcel Apfelbaum
2015-08-12 11:15 ` Michael S. Tsirkin
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