[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 1/2] libvhost-user: support resuming vq->last_av
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] libvhost-user: support resuming vq->last_avail_idx based on used_idx |
Date: |
Tue, 29 Aug 2017 18:09:32 +0300 |
On Tue, Aug 29, 2017 at 05:04:34PM +0200, Marc-André Lureau wrote:
> Hi
>
> On Tue, Aug 29, 2017 at 5:01 PM, Michael S. Tsirkin <address@hidden> wrote:
> > On Tue, Aug 29, 2017 at 04:48:04PM +0200, Marc-André Lureau wrote:
> >> This is the same workaround as commit 523b018dde3b765, which was lost
> >> with libvhost-user transition in commit e10e798c85c2331.
> >>
> >> Signed-off-by: Marc-André Lureau <address@hidden>
> >> ---
> >> contrib/libvhost-user/libvhost-user.h | 5 +++++
> >> contrib/libvhost-user/libvhost-user.c | 13 +++++++++++++
> >> 2 files changed, 18 insertions(+)
> >>
> >> diff --git a/contrib/libvhost-user/libvhost-user.h
> >> b/contrib/libvhost-user/libvhost-user.h
> >> index 53ef222c0b..aca71717c1 100644
> >> --- a/contrib/libvhost-user/libvhost-user.h
> >> +++ b/contrib/libvhost-user/libvhost-user.h
> >> @@ -132,6 +132,7 @@ typedef void (*vu_set_features_cb) (VuDev *dev,
> >> uint64_t features);
> >> typedef int (*vu_process_msg_cb) (VuDev *dev, VhostUserMsg *vmsg,
> >> int *do_reply);
> >> typedef void (*vu_queue_set_started_cb) (VuDev *dev, int qidx, bool
> >> started);
> >> +typedef bool (*vu_queue_resume_to_used_cb) (VuDev *dev, int qidx);
> >>
> >> typedef struct VuDevIface {
> >> /* called by VHOST_USER_GET_FEATURES to get the features bitmask */
> >> @@ -148,6 +149,10 @@ typedef struct VuDevIface {
> >> vu_process_msg_cb process_msg;
> >> /* tells when queues can be processed */
> >> vu_queue_set_started_cb queue_set_started;
> >> + /* If the queue must be resumed to vring.used->idx. */
> >> + /* This can help to support resuming on unmanaged exit/crash when
> >> + * the slave/driver processes elements in order. */
> >> + vu_queue_resume_to_used_cb queue_resume_to_used;
> >> } VuDevIface;
> >>
> >> typedef void (*vu_queue_handler_cb) (VuDev *dev, int qidx);
> >
> > Let's consider: this is only safe if queue is processed in order.
> > So I think that would be a better name for the field.
> >
> That's what the comment say already :)
>
> Which name do you suggest? vu_queue_is_processed_in_order?
Something like this.
> Does that
> imply it should always resume?
Not sure I understand the question.
> >
> >> diff --git a/contrib/libvhost-user/libvhost-user.c
> >> b/contrib/libvhost-user/libvhost-user.c
> >> index 35fa0c5e56..36439caed6 100644
> >> --- a/contrib/libvhost-user/libvhost-user.c
> >> +++ b/contrib/libvhost-user/libvhost-user.c
> >> @@ -521,6 +521,19 @@ vu_set_vring_addr_exec(VuDev *dev, VhostUserMsg *vmsg)
> >>
> >> vq->used_idx = vq->vring.used->idx;
> >>
> >> + if (vq->last_avail_idx != vq->used_idx) {
> >> + bool resume = dev->iface->queue_resume_to_used &&
> >> + dev->iface->queue_resume_to_used(dev, index);
> >> +
> >> + DPRINT("Last avail index != used index: %u != %u%s\n",
> >> + vq->last_avail_idx, vq->used_idx,
> >> + resume ? ", resuming" : "");
> >> +
> >> + if (resume) {
> >> + vq->shadow_avail_idx = vq->last_avail_idx = vq->used_idx;
> >> + }
> >> + }
> >> +
> >> return false;
> >> }
> >>
> >> --
> >> 2.14.1.146.gd35faa819
> >
>
>
>
> --
> Marc-André Lureau
[Qemu-devel] [PATCH 2/2] vhost-user-bridge: fix resume regression (since 2.9), Marc-André Lureau, 2017/08/29
Re: [Qemu-devel] [PATCH 0/2] vhost-user-bridge reconnect regression, Michael S. Tsirkin, 2017/08/29