Message ID | 20220706184008.1649478-15-eperezma@redhat.com |
---|---|
State | New |
Headers | show |
Series | Net Control VQ support in SVQ | expand |
在 2022/7/7 02:39, Eugenio Pérez 写道: > It allows the Shadow Control VirtQueue to wait the device to use the commands > that restore the net device state after a live migration. > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com> > --- > hw/virtio/vhost-shadow-virtqueue.h | 1 + > hw/virtio/vhost-shadow-virtqueue.c | 54 ++++++++++++++++++++++++++++-- > 2 files changed, 52 insertions(+), 3 deletions(-) > > diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h > index d01d2370db..c8668fbdd6 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.h > +++ b/hw/virtio/vhost-shadow-virtqueue.h > @@ -100,6 +100,7 @@ void vhost_svq_push_elem(VhostShadowVirtqueue *svq, > const VirtQueueElement *elem, uint32_t len); > int vhost_svq_inject(VhostShadowVirtqueue *svq, const struct iovec *iov, > size_t out_num, size_t in_num, void *opaque); > +ssize_t vhost_svq_poll(VhostShadowVirtqueue *svq); > void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd); > void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd); > void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq, > diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c > index bd9e34b413..ed7f1d0bc9 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.c > +++ b/hw/virtio/vhost-shadow-virtqueue.c > @@ -10,6 +10,8 @@ > #include "qemu/osdep.h" > #include "hw/virtio/vhost-shadow-virtqueue.h" > > +#include <glib/gpoll.h> > + > #include "qemu/error-report.h" > #include "qapi/error.h" > #include "qemu/main-loop.h" > @@ -490,10 +492,11 @@ void vhost_svq_push_elem(VhostShadowVirtqueue *svq, > } > } > > -static void vhost_svq_flush(VhostShadowVirtqueue *svq, > - bool check_for_avail_queue) > +static size_t vhost_svq_flush(VhostShadowVirtqueue *svq, > + bool check_for_avail_queue) > { > VirtQueue *vq = svq->vq; > + size_t ret = 0; > > /* Forward as many used buffers as possible. */ > do { > @@ -510,7 +513,7 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, > "More than %u used buffers obtained in a %u size SVQ", > i, svq->vring.num); > virtqueue_flush(vq, svq->vring.num); > - return; > + return ret; > } > > svq_elem = vhost_svq_get_buf(svq, &len); > @@ -520,6 +523,7 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, > > elem = g_steal_pointer(&svq_elem.opaque); > virtqueue_fill(vq, elem, len, i++); > + ret++; > } > > virtqueue_flush(vq, i); > @@ -533,6 +537,50 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, > vhost_handle_guest_kick(svq); > } > } while (!vhost_svq_enable_notification(svq)); > + > + return ret; > +} > + > +/** > + * Poll the SVQ for device used buffers. > + * > + * This function race with main event loop SVQ polling, so extra > + * synchronization is needed. > + * > + * Return the number of descriptors read from the device. > + */ > +ssize_t vhost_svq_poll(VhostShadowVirtqueue *svq) > +{ > + int fd = event_notifier_get_fd(&svq->hdev_call); > + GPollFD poll_fd = { > + .fd = fd, > + .events = G_IO_IN, > + }; > + assert(fd >= 0); > + int r = g_poll(&poll_fd, 1, -1); Any reason we can't simply (busy) polling the used ring here? It might help to reduce the latency (and it is what kernel driver uses). Thanks > + > + if (unlikely(r < 0)) { > + error_report("Cannot poll device call fd "G_POLLFD_FORMAT": (%d) %s", > + poll_fd.fd, errno, g_strerror(errno)); > + return -errno; > + } > + > + if (r == 0) { > + return 0; > + } > + > + if (unlikely(poll_fd.revents & ~(G_IO_IN))) { > + error_report( > + "Error polling device call fd "G_POLLFD_FORMAT": revents=%d", > + poll_fd.fd, poll_fd.revents); > + return -1; > + } > + > + /* > + * Max return value of vhost_svq_flush is (uint16_t)-1, so it's safe to > + * convert to ssize_t. > + */ > + return vhost_svq_flush(svq, false); > } > > /**
On Mon, Jul 11, 2022 at 11:19 AM Jason Wang <jasowang@redhat.com> wrote: > > > 在 2022/7/7 02:39, Eugenio Pérez 写道: > > It allows the Shadow Control VirtQueue to wait the device to use the commands > > that restore the net device state after a live migration. > > > > Signed-off-by: Eugenio Pérez <eperezma@redhat.com> > > --- > > hw/virtio/vhost-shadow-virtqueue.h | 1 + > > hw/virtio/vhost-shadow-virtqueue.c | 54 ++++++++++++++++++++++++++++-- > > 2 files changed, 52 insertions(+), 3 deletions(-) > > > > diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h > > index d01d2370db..c8668fbdd6 100644 > > --- a/hw/virtio/vhost-shadow-virtqueue.h > > +++ b/hw/virtio/vhost-shadow-virtqueue.h > > @@ -100,6 +100,7 @@ void vhost_svq_push_elem(VhostShadowVirtqueue *svq, > > const VirtQueueElement *elem, uint32_t len); > > int vhost_svq_inject(VhostShadowVirtqueue *svq, const struct iovec *iov, > > size_t out_num, size_t in_num, void *opaque); > > +ssize_t vhost_svq_poll(VhostShadowVirtqueue *svq); > > void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd); > > void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd); > > void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq, > > diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c > > index bd9e34b413..ed7f1d0bc9 100644 > > --- a/hw/virtio/vhost-shadow-virtqueue.c > > +++ b/hw/virtio/vhost-shadow-virtqueue.c > > @@ -10,6 +10,8 @@ > > #include "qemu/osdep.h" > > #include "hw/virtio/vhost-shadow-virtqueue.h" > > > > +#include <glib/gpoll.h> > > + > > #include "qemu/error-report.h" > > #include "qapi/error.h" > > #include "qemu/main-loop.h" > > @@ -490,10 +492,11 @@ void vhost_svq_push_elem(VhostShadowVirtqueue *svq, > > } > > } > > > > -static void vhost_svq_flush(VhostShadowVirtqueue *svq, > > - bool check_for_avail_queue) > > +static size_t vhost_svq_flush(VhostShadowVirtqueue *svq, > > + bool check_for_avail_queue) > > { > > VirtQueue *vq = svq->vq; > > + size_t ret = 0; > > > > /* Forward as many used buffers as possible. */ > > do { > > @@ -510,7 +513,7 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, > > "More than %u used buffers obtained in a %u size SVQ", > > i, svq->vring.num); > > virtqueue_flush(vq, svq->vring.num); > > - return; > > + return ret; > > } > > > > svq_elem = vhost_svq_get_buf(svq, &len); > > @@ -520,6 +523,7 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, > > > > elem = g_steal_pointer(&svq_elem.opaque); > > virtqueue_fill(vq, elem, len, i++); > > + ret++; > > } > > > > virtqueue_flush(vq, i); > > @@ -533,6 +537,50 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, > > vhost_handle_guest_kick(svq); > > } > > } while (!vhost_svq_enable_notification(svq)); > > + > > + return ret; > > +} > > + > > +/** > > + * Poll the SVQ for device used buffers. > > + * > > + * This function race with main event loop SVQ polling, so extra > > + * synchronization is needed. > > + * > > + * Return the number of descriptors read from the device. > > + */ > > +ssize_t vhost_svq_poll(VhostShadowVirtqueue *svq) > > +{ > > + int fd = event_notifier_get_fd(&svq->hdev_call); > > + GPollFD poll_fd = { > > + .fd = fd, > > + .events = G_IO_IN, > > + }; > > + assert(fd >= 0); > > + int r = g_poll(&poll_fd, 1, -1); > > > Any reason we can't simply (busy) polling the used ring here? It might > help to reduce the latency (and it is what kernel driver uses). > Yes, I'll change to a busy polling. I forgot to change it. Thanks! > Thanks > > > > + > > + if (unlikely(r < 0)) { > > + error_report("Cannot poll device call fd "G_POLLFD_FORMAT": (%d) %s", > > + poll_fd.fd, errno, g_strerror(errno)); > > + return -errno; > > + } > > + > > + if (r == 0) { > > + return 0; > > + } > > + > > + if (unlikely(poll_fd.revents & ~(G_IO_IN))) { > > + error_report( > > + "Error polling device call fd "G_POLLFD_FORMAT": revents=%d", > > + poll_fd.fd, poll_fd.revents); > > + return -1; > > + } > > + > > + /* > > + * Max return value of vhost_svq_flush is (uint16_t)-1, so it's safe to > > + * convert to ssize_t. > > + */ > > + return vhost_svq_flush(svq, false); > > } > > > > /** >
diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h index d01d2370db..c8668fbdd6 100644 --- a/hw/virtio/vhost-shadow-virtqueue.h +++ b/hw/virtio/vhost-shadow-virtqueue.h @@ -100,6 +100,7 @@ void vhost_svq_push_elem(VhostShadowVirtqueue *svq, const VirtQueueElement *elem, uint32_t len); int vhost_svq_inject(VhostShadowVirtqueue *svq, const struct iovec *iov, size_t out_num, size_t in_num, void *opaque); +ssize_t vhost_svq_poll(VhostShadowVirtqueue *svq); void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd); void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd); void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq, diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index bd9e34b413..ed7f1d0bc9 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -10,6 +10,8 @@ #include "qemu/osdep.h" #include "hw/virtio/vhost-shadow-virtqueue.h" +#include <glib/gpoll.h> + #include "qemu/error-report.h" #include "qapi/error.h" #include "qemu/main-loop.h" @@ -490,10 +492,11 @@ void vhost_svq_push_elem(VhostShadowVirtqueue *svq, } } -static void vhost_svq_flush(VhostShadowVirtqueue *svq, - bool check_for_avail_queue) +static size_t vhost_svq_flush(VhostShadowVirtqueue *svq, + bool check_for_avail_queue) { VirtQueue *vq = svq->vq; + size_t ret = 0; /* Forward as many used buffers as possible. */ do { @@ -510,7 +513,7 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, "More than %u used buffers obtained in a %u size SVQ", i, svq->vring.num); virtqueue_flush(vq, svq->vring.num); - return; + return ret; } svq_elem = vhost_svq_get_buf(svq, &len); @@ -520,6 +523,7 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, elem = g_steal_pointer(&svq_elem.opaque); virtqueue_fill(vq, elem, len, i++); + ret++; } virtqueue_flush(vq, i); @@ -533,6 +537,50 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq, vhost_handle_guest_kick(svq); } } while (!vhost_svq_enable_notification(svq)); + + return ret; +} + +/** + * Poll the SVQ for device used buffers. + * + * This function race with main event loop SVQ polling, so extra + * synchronization is needed. + * + * Return the number of descriptors read from the device. + */ +ssize_t vhost_svq_poll(VhostShadowVirtqueue *svq) +{ + int fd = event_notifier_get_fd(&svq->hdev_call); + GPollFD poll_fd = { + .fd = fd, + .events = G_IO_IN, + }; + assert(fd >= 0); + int r = g_poll(&poll_fd, 1, -1); + + if (unlikely(r < 0)) { + error_report("Cannot poll device call fd "G_POLLFD_FORMAT": (%d) %s", + poll_fd.fd, errno, g_strerror(errno)); + return -errno; + } + + if (r == 0) { + return 0; + } + + if (unlikely(poll_fd.revents & ~(G_IO_IN))) { + error_report( + "Error polling device call fd "G_POLLFD_FORMAT": revents=%d", + poll_fd.fd, poll_fd.revents); + return -1; + } + + /* + * Max return value of vhost_svq_flush is (uint16_t)-1, so it's safe to + * convert to ssize_t. + */ + return vhost_svq_flush(svq, false); } /**
It allows the Shadow Control VirtQueue to wait the device to use the commands that restore the net device state after a live migration. Signed-off-by: Eugenio Pérez <eperezma@redhat.com> --- hw/virtio/vhost-shadow-virtqueue.h | 1 + hw/virtio/vhost-shadow-virtqueue.c | 54 ++++++++++++++++++++++++++++-- 2 files changed, 52 insertions(+), 3 deletions(-)