* [dpdk-stable] [PATCH] vhost: fix vhost interrupt support
@ 2018-09-04 23:55 Tiwei Bie
2018-09-10 7:22 ` Maxime Coquelin
2018-09-10 13:47 ` Maxime Coquelin
0 siblings, 2 replies; 7+ messages in thread
From: Tiwei Bie @ 2018-09-04 23:55 UTC (permalink / raw)
To: maxime.coquelin, zhihong.wang, dev; +Cc: stable
When VIRTIO_RING_F_EVENT_IDX is negotiated, we need to
update the avail event to enable the notification.
Fixes: 3f8ff12821e4 ("vhost: support interrupt mode")
Cc: stable@dpdk.org
Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
---
lib/librte_vhost/Makefile | 1 +
lib/librte_vhost/vhost.c | 18 ++++++++++++------
lib/librte_vhost/vhost.h | 2 ++
3 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
index de431fbb7..531cf4832 100644
--- a/lib/librte_vhost/Makefile
+++ b/lib/librte_vhost/Makefile
@@ -13,6 +13,7 @@ LIBABIVER := 4
CFLAGS += -DALLOW_EXPERIMENTAL_API
CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -D_FILE_OFFSET_BITS=64
CFLAGS += -I vhost_user
+CFLAGS += -fno-strict-aliasing
LDLIBS += -lpthread
ifeq ($(CONFIG_RTE_LIBRTE_VHOST_NUMA),y)
diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 3c9be10a0..88b1781d5 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -646,12 +646,18 @@ rte_vhost_avail_entries(int vid, uint16_t queue_id)
}
static inline void
-vhost_enable_notify_split(struct vhost_virtqueue *vq, int enable)
+vhost_enable_notify_split(struct virtio_net *dev,
+ struct vhost_virtqueue *vq, int enable)
{
- if (enable)
- vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
- else
- vq->used->flags |= VRING_USED_F_NO_NOTIFY;
+ if (!(dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))) {
+ if (enable)
+ vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
+ else
+ vq->used->flags |= VRING_USED_F_NO_NOTIFY;
+ } else {
+ if (enable)
+ vhost_avail_event(vq) = vq->last_avail_idx;
+ }
}
static inline void
@@ -689,7 +695,7 @@ rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable)
if (vq_is_packed(dev))
vhost_enable_notify_packed(dev, vq, enable);
else
- vhost_enable_notify_split(vq, enable);
+ vhost_enable_notify_split(dev, vq, enable);
return 0;
}
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index 760a09c0d..25ffd7614 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -648,6 +648,8 @@ vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
return __vhost_iova_to_vva(dev, vq, iova, len, perm);
}
+#define vhost_avail_event(vr) \
+ (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
#define vhost_used_event(vr) \
(*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
--
2.18.0
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [dpdk-stable] [PATCH] vhost: fix vhost interrupt support
2018-09-04 23:55 [dpdk-stable] [PATCH] vhost: fix vhost interrupt support Tiwei Bie
@ 2018-09-10 7:22 ` Maxime Coquelin
2018-09-10 7:36 ` Tiwei Bie
2018-09-10 13:47 ` Maxime Coquelin
1 sibling, 1 reply; 7+ messages in thread
From: Maxime Coquelin @ 2018-09-10 7:22 UTC (permalink / raw)
To: Tiwei Bie, zhihong.wang, dev; +Cc: stable
Hi Tiwei,
On 09/05/2018 01:55 AM, Tiwei Bie wrote:
> When VIRTIO_RING_F_EVENT_IDX is negotiated, we need to
> update the avail event to enable the notification.
>
> Fixes: 3f8ff12821e4 ("vhost: support interrupt mode")
> Cc: stable@dpdk.org
>
> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> ---
> lib/librte_vhost/Makefile | 1 +
> lib/librte_vhost/vhost.c | 18 ++++++++++++------
> lib/librte_vhost/vhost.h | 2 ++
> 3 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
> index de431fbb7..531cf4832 100644
> --- a/lib/librte_vhost/Makefile
> +++ b/lib/librte_vhost/Makefile
> @@ -13,6 +13,7 @@ LIBABIVER := 4
> CFLAGS += -DALLOW_EXPERIMENTAL_API
> CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -D_FILE_OFFSET_BITS=64
> CFLAGS += -I vhost_user
> +CFLAGS += -fno-strict-aliasing
I'm not clear why this is needed looking at the code below,
could you please explain?
> LDLIBS += -lpthread
>
> ifeq ($(CONFIG_RTE_LIBRTE_VHOST_NUMA),y)
> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> index 3c9be10a0..88b1781d5 100644
> --- a/lib/librte_vhost/vhost.c
> +++ b/lib/librte_vhost/vhost.c
> @@ -646,12 +646,18 @@ rte_vhost_avail_entries(int vid, uint16_t queue_id)
> }
>
> static inline void
> -vhost_enable_notify_split(struct vhost_virtqueue *vq, int enable)
> +vhost_enable_notify_split(struct virtio_net *dev,
> + struct vhost_virtqueue *vq, int enable)
> {
> - if (enable)
> - vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
> - else
> - vq->used->flags |= VRING_USED_F_NO_NOTIFY;
> + if (!(dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))) {
> + if (enable)
> + vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
> + else
> + vq->used->flags |= VRING_USED_F_NO_NOTIFY;
> + } else {
> + if (enable)
> + vhost_avail_event(vq) = vq->last_avail_idx;
> + }
> }
>
> static inline void
> @@ -689,7 +695,7 @@ rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable)
> if (vq_is_packed(dev))
> vhost_enable_notify_packed(dev, vq, enable);
> else
> - vhost_enable_notify_split(vq, enable);
> + vhost_enable_notify_split(dev, vq, enable);
>
> return 0;
> }
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 760a09c0d..25ffd7614 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -648,6 +648,8 @@ vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
> return __vhost_iova_to_vva(dev, vq, iova, len, perm);
> }
>
> +#define vhost_avail_event(vr) \
> + (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
> #define vhost_used_event(vr) \
> (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [dpdk-stable] [PATCH] vhost: fix vhost interrupt support
2018-09-10 7:22 ` Maxime Coquelin
@ 2018-09-10 7:36 ` Tiwei Bie
2018-09-10 7:48 ` Maxime Coquelin
2018-09-14 12:10 ` Ferruh Yigit
0 siblings, 2 replies; 7+ messages in thread
From: Tiwei Bie @ 2018-09-10 7:36 UTC (permalink / raw)
To: Maxime Coquelin; +Cc: zhihong.wang, dev, stable
Hi Maxime,
On Mon, Sep 10, 2018 at 09:22:00AM +0200, Maxime Coquelin wrote:
> Hi Tiwei,
>
> On 09/05/2018 01:55 AM, Tiwei Bie wrote:
> > When VIRTIO_RING_F_EVENT_IDX is negotiated, we need to
> > update the avail event to enable the notification.
> >
> > Fixes: 3f8ff12821e4 ("vhost: support interrupt mode")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> > ---
> > lib/librte_vhost/Makefile | 1 +
> > lib/librte_vhost/vhost.c | 18 ++++++++++++------
> > lib/librte_vhost/vhost.h | 2 ++
> > 3 files changed, 15 insertions(+), 6 deletions(-)
> >
> > diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
> > index de431fbb7..531cf4832 100644
> > --- a/lib/librte_vhost/Makefile
> > +++ b/lib/librte_vhost/Makefile
> > @@ -13,6 +13,7 @@ LIBABIVER := 4
> > CFLAGS += -DALLOW_EXPERIMENTAL_API
> > CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -D_FILE_OFFSET_BITS=64
> > CFLAGS += -I vhost_user
> > +CFLAGS += -fno-strict-aliasing
>
> I'm not clear why this is needed looking at the code below,
> could you please explain?
Without this, we will get below build error:
lib/librte_vhost/vhost.c: In function ‘vhost_enable_notify_split’:
lib/librte_vhost/vhost.h:656:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
(*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lib/librte_vhost/vhost.c:659:4: note: in expansion of macro ‘vhost_avail_event’
vhost_avail_event(vq) = vq->last_avail_idx;
^~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
>
> > LDLIBS += -lpthread
> > ifeq ($(CONFIG_RTE_LIBRTE_VHOST_NUMA),y)
> > diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> > index 3c9be10a0..88b1781d5 100644
> > --- a/lib/librte_vhost/vhost.c
> > +++ b/lib/librte_vhost/vhost.c
> > @@ -646,12 +646,18 @@ rte_vhost_avail_entries(int vid, uint16_t queue_id)
> > }
> > static inline void
> > -vhost_enable_notify_split(struct vhost_virtqueue *vq, int enable)
> > +vhost_enable_notify_split(struct virtio_net *dev,
> > + struct vhost_virtqueue *vq, int enable)
> > {
> > - if (enable)
> > - vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
> > - else
> > - vq->used->flags |= VRING_USED_F_NO_NOTIFY;
> > + if (!(dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))) {
> > + if (enable)
> > + vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
> > + else
> > + vq->used->flags |= VRING_USED_F_NO_NOTIFY;
> > + } else {
> > + if (enable)
> > + vhost_avail_event(vq) = vq->last_avail_idx;
> > + }
> > }
> > static inline void
> > @@ -689,7 +695,7 @@ rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable)
> > if (vq_is_packed(dev))
> > vhost_enable_notify_packed(dev, vq, enable);
> > else
> > - vhost_enable_notify_split(vq, enable);
> > + vhost_enable_notify_split(dev, vq, enable);
> > return 0;
> > }
> > diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> > index 760a09c0d..25ffd7614 100644
> > --- a/lib/librte_vhost/vhost.h
> > +++ b/lib/librte_vhost/vhost.h
> > @@ -648,6 +648,8 @@ vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
> > return __vhost_iova_to_vva(dev, vq, iova, len, perm);
> > }
> > +#define vhost_avail_event(vr) \
> > + (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
> > #define vhost_used_event(vr) \
> > (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> >
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [dpdk-stable] [PATCH] vhost: fix vhost interrupt support
2018-09-10 7:36 ` Tiwei Bie
@ 2018-09-10 7:48 ` Maxime Coquelin
2018-09-14 12:10 ` Ferruh Yigit
1 sibling, 0 replies; 7+ messages in thread
From: Maxime Coquelin @ 2018-09-10 7:48 UTC (permalink / raw)
To: Tiwei Bie; +Cc: zhihong.wang, dev, stable
On 09/10/2018 09:36 AM, Tiwei Bie wrote:
> Hi Maxime,
>
> On Mon, Sep 10, 2018 at 09:22:00AM +0200, Maxime Coquelin wrote:
>> Hi Tiwei,
>>
>> On 09/05/2018 01:55 AM, Tiwei Bie wrote:
>>> When VIRTIO_RING_F_EVENT_IDX is negotiated, we need to
>>> update the avail event to enable the notification.
>>>
>>> Fixes: 3f8ff12821e4 ("vhost: support interrupt mode")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
>>> ---
>>> lib/librte_vhost/Makefile | 1 +
>>> lib/librte_vhost/vhost.c | 18 ++++++++++++------
>>> lib/librte_vhost/vhost.h | 2 ++
>>> 3 files changed, 15 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
>>> index de431fbb7..531cf4832 100644
>>> --- a/lib/librte_vhost/Makefile
>>> +++ b/lib/librte_vhost/Makefile
>>> @@ -13,6 +13,7 @@ LIBABIVER := 4
>>> CFLAGS += -DALLOW_EXPERIMENTAL_API
>>> CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -D_FILE_OFFSET_BITS=64
>>> CFLAGS += -I vhost_user
>>> +CFLAGS += -fno-strict-aliasing
>>
>> I'm not clear why this is needed looking at the code below,
>> could you please explain?
>
> Without this, we will get below build error:
>
> lib/librte_vhost/vhost.c: In function ‘vhost_enable_notify_split’:
> lib/librte_vhost/vhost.h:656:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
> (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/librte_vhost/vhost.c:659:4: note: in expansion of macro ‘vhost_avail_event’
> vhost_avail_event(vq) = vq->last_avail_idx;
> ^~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
OK, thanks for the info.
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Maxime
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [dpdk-stable] [PATCH] vhost: fix vhost interrupt support
2018-09-04 23:55 [dpdk-stable] [PATCH] vhost: fix vhost interrupt support Tiwei Bie
2018-09-10 7:22 ` Maxime Coquelin
@ 2018-09-10 13:47 ` Maxime Coquelin
1 sibling, 0 replies; 7+ messages in thread
From: Maxime Coquelin @ 2018-09-10 13:47 UTC (permalink / raw)
To: Tiwei Bie, zhihong.wang, dev; +Cc: stable
On 09/05/2018 01:55 AM, Tiwei Bie wrote:
> When VIRTIO_RING_F_EVENT_IDX is negotiated, we need to
> update the avail event to enable the notification.
>
> Fixes: 3f8ff12821e4 ("vhost: support interrupt mode")
> Cc:stable@dpdk.org
>
> Signed-off-by: Tiwei Bie<tiwei.bie@intel.com>
> ---
> lib/librte_vhost/Makefile | 1 +
> lib/librte_vhost/vhost.c | 18 ++++++++++++------
> lib/librte_vhost/vhost.h | 2 ++
> 3 files changed, 15 insertions(+), 6 deletions(-)
Applied to dpdk-next-virtio/master.
Thanks!
Maxime
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [dpdk-stable] [PATCH] vhost: fix vhost interrupt support
2018-09-10 7:36 ` Tiwei Bie
2018-09-10 7:48 ` Maxime Coquelin
@ 2018-09-14 12:10 ` Ferruh Yigit
2018-09-14 14:51 ` Tiwei Bie
1 sibling, 1 reply; 7+ messages in thread
From: Ferruh Yigit @ 2018-09-14 12:10 UTC (permalink / raw)
To: Tiwei Bie, Maxime Coquelin; +Cc: zhihong.wang, dev, stable
On 9/10/2018 8:36 AM, Tiwei Bie wrote:
> Hi Maxime,
>
> On Mon, Sep 10, 2018 at 09:22:00AM +0200, Maxime Coquelin wrote:
>> Hi Tiwei,
>>
>> On 09/05/2018 01:55 AM, Tiwei Bie wrote:
>>> When VIRTIO_RING_F_EVENT_IDX is negotiated, we need to
>>> update the avail event to enable the notification.
>>>
>>> Fixes: 3f8ff12821e4 ("vhost: support interrupt mode")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
>>> ---
>>> lib/librte_vhost/Makefile | 1 +
>>> lib/librte_vhost/vhost.c | 18 ++++++++++++------
>>> lib/librte_vhost/vhost.h | 2 ++
>>> 3 files changed, 15 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
>>> index de431fbb7..531cf4832 100644
>>> --- a/lib/librte_vhost/Makefile
>>> +++ b/lib/librte_vhost/Makefile
>>> @@ -13,6 +13,7 @@ LIBABIVER := 4
>>> CFLAGS += -DALLOW_EXPERIMENTAL_API
>>> CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -D_FILE_OFFSET_BITS=64
>>> CFLAGS += -I vhost_user
>>> +CFLAGS += -fno-strict-aliasing
>>
>> I'm not clear why this is needed looking at the code below,
>> could you please explain?
>
> Without this, we will get below build error:
>
> lib/librte_vhost/vhost.c: In function ‘vhost_enable_notify_split’:
> lib/librte_vhost/vhost.h:656:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
> (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> lib/librte_vhost/vhost.c:659:4: note: in expansion of macro ‘vhost_avail_event’
> vhost_avail_event(vq) = vq->last_avail_idx;
> ^~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors
>
Getting this error with meson build system, since "-fno-strict-aliasing" is not
added to meson build file. BUT instead of disabling compiler warning,
first element of the "struct vring_used_elem ring[0]" is "uint32_t id;", so it
should be accessed as uint32_t. What about following:
#define vhost_avail_event(vr) \
- (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
+ (*(volatile uint32_t*)&(vr)->used->ring[(vr)->size])
And for "vhost_avail_event(vq) = vq->last_avail_idx;", "last_avail_idx" is
uint16_t, so assigning from uint16_t to uint32_t should be ok too.
If above works for you please send a patch for update also removing
"-fno-strict-aliasing", this can be rebased on existing patch.
If not works, please at least send a patch to add flag to meson build file
Thanks,
ferruh
>>
>>> LDLIBS += -lpthread
>>> ifeq ($(CONFIG_RTE_LIBRTE_VHOST_NUMA),y)
>>> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
>>> index 3c9be10a0..88b1781d5 100644
>>> --- a/lib/librte_vhost/vhost.c
>>> +++ b/lib/librte_vhost/vhost.c
>>> @@ -646,12 +646,18 @@ rte_vhost_avail_entries(int vid, uint16_t queue_id)
>>> }
>>> static inline void
>>> -vhost_enable_notify_split(struct vhost_virtqueue *vq, int enable)
>>> +vhost_enable_notify_split(struct virtio_net *dev,
>>> + struct vhost_virtqueue *vq, int enable)
>>> {
>>> - if (enable)
>>> - vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
>>> - else
>>> - vq->used->flags |= VRING_USED_F_NO_NOTIFY;
>>> + if (!(dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))) {
>>> + if (enable)
>>> + vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
>>> + else
>>> + vq->used->flags |= VRING_USED_F_NO_NOTIFY;
>>> + } else {
>>> + if (enable)
>>> + vhost_avail_event(vq) = vq->last_avail_idx;
>>> + }
>>> }
>>> static inline void
>>> @@ -689,7 +695,7 @@ rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable)
>>> if (vq_is_packed(dev))
>>> vhost_enable_notify_packed(dev, vq, enable);
>>> else
>>> - vhost_enable_notify_split(vq, enable);
>>> + vhost_enable_notify_split(dev, vq, enable);
>>> return 0;
>>> }
>>> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
>>> index 760a09c0d..25ffd7614 100644
>>> --- a/lib/librte_vhost/vhost.h
>>> +++ b/lib/librte_vhost/vhost.h
>>> @@ -648,6 +648,8 @@ vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
>>> return __vhost_iova_to_vva(dev, vq, iova, len, perm);
>>> }
>>> +#define vhost_avail_event(vr) \
>>> + (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
>>> #define vhost_used_event(vr) \
>>> (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
>>>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [dpdk-stable] [PATCH] vhost: fix vhost interrupt support
2018-09-14 12:10 ` Ferruh Yigit
@ 2018-09-14 14:51 ` Tiwei Bie
0 siblings, 0 replies; 7+ messages in thread
From: Tiwei Bie @ 2018-09-14 14:51 UTC (permalink / raw)
To: Ferruh Yigit; +Cc: Maxime Coquelin, zhihong.wang, dev, stable
On Fri, Sep 14, 2018 at 01:10:07PM +0100, Ferruh Yigit wrote:
> On 9/10/2018 8:36 AM, Tiwei Bie wrote:
> > Hi Maxime,
> >
> > On Mon, Sep 10, 2018 at 09:22:00AM +0200, Maxime Coquelin wrote:
> >> Hi Tiwei,
> >>
> >> On 09/05/2018 01:55 AM, Tiwei Bie wrote:
> >>> When VIRTIO_RING_F_EVENT_IDX is negotiated, we need to
> >>> update the avail event to enable the notification.
> >>>
> >>> Fixes: 3f8ff12821e4 ("vhost: support interrupt mode")
> >>> Cc: stable@dpdk.org
> >>>
> >>> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> >>> ---
> >>> lib/librte_vhost/Makefile | 1 +
> >>> lib/librte_vhost/vhost.c | 18 ++++++++++++------
> >>> lib/librte_vhost/vhost.h | 2 ++
> >>> 3 files changed, 15 insertions(+), 6 deletions(-)
> >>>
> >>> diff --git a/lib/librte_vhost/Makefile b/lib/librte_vhost/Makefile
> >>> index de431fbb7..531cf4832 100644
> >>> --- a/lib/librte_vhost/Makefile
> >>> +++ b/lib/librte_vhost/Makefile
> >>> @@ -13,6 +13,7 @@ LIBABIVER := 4
> >>> CFLAGS += -DALLOW_EXPERIMENTAL_API
> >>> CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3 -D_FILE_OFFSET_BITS=64
> >>> CFLAGS += -I vhost_user
> >>> +CFLAGS += -fno-strict-aliasing
> >>
> >> I'm not clear why this is needed looking at the code below,
> >> could you please explain?
> >
> > Without this, we will get below build error:
> >
> > lib/librte_vhost/vhost.c: In function ‘vhost_enable_notify_split’:
> > lib/librte_vhost/vhost.h:656:4: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
> > (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
> > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > lib/librte_vhost/vhost.c:659:4: note: in expansion of macro ‘vhost_avail_event’
> > vhost_avail_event(vq) = vq->last_avail_idx;
> > ^~~~~~~~~~~~~~~~~
> > cc1: all warnings being treated as errors
> >
>
> Getting this error with meson build system, since "-fno-strict-aliasing" is not
> added to meson build file.
Thanks! I didn't notice this. I just tried the meson build manually.
The warning isn't treated as errors on my side. So it was not caught
by the build script..
> BUT instead of disabling compiler warning,
>
> first element of the "struct vring_used_elem ring[0]" is "uint32_t id;", so it
> should be accessed as uint32_t. What about following:
>
> #define vhost_avail_event(vr) \
> - (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
> + (*(volatile uint32_t*)&(vr)->used->ring[(vr)->size])
>
> And for "vhost_avail_event(vq) = vq->last_avail_idx;", "last_avail_idx" is
> uint16_t, so assigning from uint16_t to uint32_t should be ok too.
At the end of used ring, there is a 16bits event_idx. It can't
be interpreted as a vring_used_elem and it's also not part of a
vring_used_elem. This is the traditional way how we access it:
https://github.com/torvalds/linux/blob/a06b0c82a049/drivers/vhost/vhost.c#L50
https://github.com/freebsd/freebsd/blob/209b94df8701/sys/dev/virtio/virtio_ring.h#L133
>
> If above works for you please send a patch for update also removing
> "-fno-strict-aliasing", this can be rebased on existing patch.
>
> If not works, please at least send a patch to add flag to meson build file
I'll send a patch to add flag to meson build file.
Thanks!
>
> Thanks,
> ferruh
>
> >>
> >>> LDLIBS += -lpthread
> >>> ifeq ($(CONFIG_RTE_LIBRTE_VHOST_NUMA),y)
> >>> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> >>> index 3c9be10a0..88b1781d5 100644
> >>> --- a/lib/librte_vhost/vhost.c
> >>> +++ b/lib/librte_vhost/vhost.c
> >>> @@ -646,12 +646,18 @@ rte_vhost_avail_entries(int vid, uint16_t queue_id)
> >>> }
> >>> static inline void
> >>> -vhost_enable_notify_split(struct vhost_virtqueue *vq, int enable)
> >>> +vhost_enable_notify_split(struct virtio_net *dev,
> >>> + struct vhost_virtqueue *vq, int enable)
> >>> {
> >>> - if (enable)
> >>> - vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
> >>> - else
> >>> - vq->used->flags |= VRING_USED_F_NO_NOTIFY;
> >>> + if (!(dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))) {
> >>> + if (enable)
> >>> + vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
> >>> + else
> >>> + vq->used->flags |= VRING_USED_F_NO_NOTIFY;
> >>> + } else {
> >>> + if (enable)
> >>> + vhost_avail_event(vq) = vq->last_avail_idx;
> >>> + }
> >>> }
> >>> static inline void
> >>> @@ -689,7 +695,7 @@ rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable)
> >>> if (vq_is_packed(dev))
> >>> vhost_enable_notify_packed(dev, vq, enable);
> >>> else
> >>> - vhost_enable_notify_split(vq, enable);
> >>> + vhost_enable_notify_split(dev, vq, enable);
> >>> return 0;
> >>> }
> >>> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> >>> index 760a09c0d..25ffd7614 100644
> >>> --- a/lib/librte_vhost/vhost.h
> >>> +++ b/lib/librte_vhost/vhost.h
> >>> @@ -648,6 +648,8 @@ vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
> >>> return __vhost_iova_to_vva(dev, vq, iova, len, perm);
> >>> }
> >>> +#define vhost_avail_event(vr) \
> >>> + (*(volatile uint16_t*)&(vr)->used->ring[(vr)->size])
> >>> #define vhost_used_event(vr) \
> >>> (*(volatile uint16_t*)&(vr)->avail->ring[(vr)->size])
> >>>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2018-09-14 14:52 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-09-04 23:55 [dpdk-stable] [PATCH] vhost: fix vhost interrupt support Tiwei Bie
2018-09-10 7:22 ` Maxime Coquelin
2018-09-10 7:36 ` Tiwei Bie
2018-09-10 7:48 ` Maxime Coquelin
2018-09-14 12:10 ` Ferruh Yigit
2018-09-14 14:51 ` Tiwei Bie
2018-09-10 13:47 ` Maxime Coquelin
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