Jason Wang
2022-Feb-28 02:57 UTC
[PATCH v2 02/14] vhost: Add Shadow VirtQueue kick forwarding capabilities
? 2022/2/27 ??9:40, Eugenio P?rez ??:> At this mode no buffer forwarding will be performed in SVQ mode: Qemu > will just forward the guest's kicks to the device. > > Host memory notifiers regions are left out for simplicity, and they will > not be addressed in this series. > > Signed-off-by: Eugenio P?rez <eperezma at redhat.com> > --- > hw/virtio/vhost-shadow-virtqueue.h | 14 +++ > include/hw/virtio/vhost-vdpa.h | 4 + > hw/virtio/vhost-shadow-virtqueue.c | 52 +++++++++++ > hw/virtio/vhost-vdpa.c | 145 ++++++++++++++++++++++++++++- > 4 files changed, 213 insertions(+), 2 deletions(-) > > diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h > index f1519e3c7b..1cbc87d5d8 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.h > +++ b/hw/virtio/vhost-shadow-virtqueue.h > @@ -18,8 +18,22 @@ typedef struct VhostShadowVirtqueue { > EventNotifier hdev_kick; > /* Shadow call notifier, sent to vhost */ > EventNotifier hdev_call; > + > + /* > + * Borrowed virtqueue's guest to host notifier. To borrow it in this event > + * notifier allows to recover the VhostShadowVirtqueue from the event loop > + * easily. If we use the VirtQueue's one, we don't have an easy way to > + * retrieve VhostShadowVirtqueue. > + * > + * So shadow virtqueue must not clean it, or we would lose VirtQueue one. > + */ > + EventNotifier svq_kick; > } VhostShadowVirtqueue; > > +void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd); > + > +void vhost_svq_stop(VhostShadowVirtqueue *svq); > + > VhostShadowVirtqueue *vhost_svq_new(void); > > void vhost_svq_free(gpointer vq); > diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h > index 3ce79a646d..009a9f3b6b 100644 > --- a/include/hw/virtio/vhost-vdpa.h > +++ b/include/hw/virtio/vhost-vdpa.h > @@ -12,6 +12,8 @@ > #ifndef HW_VIRTIO_VHOST_VDPA_H > #define HW_VIRTIO_VHOST_VDPA_H > > +#include <gmodule.h> > + > #include "hw/virtio/virtio.h" > #include "standard-headers/linux/vhost_types.h" > > @@ -27,6 +29,8 @@ typedef struct vhost_vdpa { > bool iotlb_batch_begin_sent; > MemoryListener listener; > struct vhost_vdpa_iova_range iova_range; > + bool shadow_vqs_enabled; > + GPtrArray *shadow_vqs; > struct vhost_dev *dev; > VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX]; > } VhostVDPA; > diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c > index 019cf1950f..a5d0659f86 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.c > +++ b/hw/virtio/vhost-shadow-virtqueue.c > @@ -11,6 +11,56 @@ > #include "hw/virtio/vhost-shadow-virtqueue.h" > > #include "qemu/error-report.h" > +#include "qemu/main-loop.h" > +#include "linux-headers/linux/vhost.h" > + > +/** Forward guest notifications */ > +static void vhost_handle_guest_kick(EventNotifier *n) > +{ > + VhostShadowVirtqueue *svq = container_of(n, VhostShadowVirtqueue, > + svq_kick); > + event_notifier_test_and_clear(n); > + event_notifier_set(&svq->hdev_kick); > +} > + > +/** > + * Set a new file descriptor for the guest to kick the SVQ and notify for avail > + * > + * @svq The svq > + * @svq_kick_fd The svq kick fd > + * > + * Note that the SVQ will never close the old file descriptor. > + */ > +void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd) > +{ > + EventNotifier *svq_kick = &svq->svq_kick; > + bool poll_stop = VHOST_FILE_UNBIND != event_notifier_get_fd(svq_kick);I wonder if this is robust. E.g is there any chance that may end up with both poll_stop and poll_start are false? If not, can we simple detect poll_stop as below and treat !poll_start and poll_stop? Other looks good. Thanks> + bool poll_start = svq_kick_fd != VHOST_FILE_UNBIND; > + > + if (poll_stop) { > + event_notifier_set_handler(svq_kick, NULL); > + } > + > + /* > + * event_notifier_set_handler already checks for guest's notifications if > + * they arrive at the new file descriptor in the switch, so there is no > + * need to explicitly check for them. > + */ > + if (poll_start) { > + event_notifier_init_fd(svq_kick, svq_kick_fd); > + event_notifier_set(svq_kick); > + event_notifier_set_handler(svq_kick, vhost_handle_guest_kick); > + } > +} > + > +/** > + * Stop the shadow virtqueue operation. > + * @svq Shadow Virtqueue > + */ > +void vhost_svq_stop(VhostShadowVirtqueue *svq) > +{ > + event_notifier_set_handler(&svq->svq_kick, NULL); > +} > > /** > * Creates vhost shadow virtqueue, and instructs the vhost device to use the > @@ -39,6 +89,7 @@ VhostShadowVirtqueue *vhost_svq_new(void) > goto err_init_hdev_call; > } > > + event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND); > return g_steal_pointer(&svq); > > err_init_hdev_call: > @@ -56,6 +107,7 @@ err_init_hdev_kick: > void vhost_svq_free(gpointer pvq) > { > VhostShadowVirtqueue *vq = pvq; > + vhost_svq_stop(vq); > event_notifier_cleanup(&vq->hdev_kick); > event_notifier_cleanup(&vq->hdev_call); > g_free(vq); > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c > index 04ea43704f..454bf50735 100644 > --- a/hw/virtio/vhost-vdpa.c > +++ b/hw/virtio/vhost-vdpa.c > @@ -17,12 +17,14 @@ > #include "hw/virtio/vhost.h" > #include "hw/virtio/vhost-backend.h" > #include "hw/virtio/virtio-net.h" > +#include "hw/virtio/vhost-shadow-virtqueue.h" > #include "hw/virtio/vhost-vdpa.h" > #include "exec/address-spaces.h" > #include "qemu/main-loop.h" > #include "cpu.h" > #include "trace.h" > #include "qemu-common.h" > +#include "qapi/error.h" > > /* > * Return one past the end of the end of section. Be careful with uint64_t > @@ -342,6 +344,30 @@ static bool vhost_vdpa_one_time_request(struct vhost_dev *dev) > return v->index != 0; > } > > +static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v, > + Error **errp) > +{ > + g_autoptr(GPtrArray) shadow_vqs = NULL; > + > + if (!v->shadow_vqs_enabled) { > + return 0; > + } > + > + shadow_vqs = g_ptr_array_new_full(hdev->nvqs, vhost_svq_free); > + for (unsigned n = 0; n < hdev->nvqs; ++n) { > + g_autoptr(VhostShadowVirtqueue) svq = vhost_svq_new(); > + > + if (unlikely(!svq)) { > + error_setg(errp, "Cannot create svq %u", n); > + return -1; > + } > + g_ptr_array_add(shadow_vqs, g_steal_pointer(&svq)); > + } > + > + v->shadow_vqs = g_steal_pointer(&shadow_vqs); > + return 0; > +} > + > static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp) > { > struct vhost_vdpa *v; > @@ -364,6 +390,10 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp) > dev->opaque = opaque ; > v->listener = vhost_vdpa_memory_listener; > v->msg_type = VHOST_IOTLB_MSG_V2; > + ret = vhost_vdpa_init_svq(dev, v, errp); > + if (ret) { > + goto err; > + } > > vhost_vdpa_get_iova_range(v); > > @@ -375,6 +405,10 @@ static int vhost_vdpa_init(struct vhost_dev *dev, void *opaque, Error **errp) > VIRTIO_CONFIG_S_DRIVER); > > return 0; > + > +err: > + ram_block_discard_disable(false); > + return ret; > } > > static void vhost_vdpa_host_notifier_uninit(struct vhost_dev *dev, > @@ -444,8 +478,14 @@ err: > > static void vhost_vdpa_host_notifiers_init(struct vhost_dev *dev) > { > + struct vhost_vdpa *v = dev->opaque; > int i; > > + if (v->shadow_vqs_enabled) { > + /* FIXME SVQ is not compatible with host notifiers mr */ > + return; > + } > + > for (i = dev->vq_index; i < dev->vq_index + dev->nvqs; i++) { > if (vhost_vdpa_host_notifier_init(dev, i)) { > goto err; > @@ -459,6 +499,21 @@ err: > return; > } > > +static void vhost_vdpa_svq_cleanup(struct vhost_dev *dev) > +{ > + struct vhost_vdpa *v = dev->opaque; > + size_t idx; > + > + if (!v->shadow_vqs) { > + return; > + } > + > + for (idx = 0; idx < v->shadow_vqs->len; ++idx) { > + vhost_svq_stop(g_ptr_array_index(v->shadow_vqs, idx)); > + } > + g_ptr_array_free(v->shadow_vqs, true); > +} > + > static int vhost_vdpa_cleanup(struct vhost_dev *dev) > { > struct vhost_vdpa *v; > @@ -467,6 +522,7 @@ static int vhost_vdpa_cleanup(struct vhost_dev *dev) > trace_vhost_vdpa_cleanup(dev, v); > vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs); > memory_listener_unregister(&v->listener); > + vhost_vdpa_svq_cleanup(dev); > > dev->opaque = NULL; > ram_block_discard_disable(false); > @@ -558,11 +614,26 @@ static int vhost_vdpa_get_device_id(struct vhost_dev *dev, > return ret; > } > > +static void vhost_vdpa_reset_svq(struct vhost_vdpa *v) > +{ > + if (!v->shadow_vqs_enabled) { > + return; > + } > + > + for (unsigned i = 0; i < v->shadow_vqs->len; ++i) { > + VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i); > + vhost_svq_stop(svq); > + } > +} > + > static int vhost_vdpa_reset_device(struct vhost_dev *dev) > { > + struct vhost_vdpa *v = dev->opaque; > int ret; > uint8_t status = 0; > > + vhost_vdpa_reset_svq(v); > + > ret = vhost_vdpa_call(dev, VHOST_VDPA_SET_STATUS, &status); > trace_vhost_vdpa_reset_device(dev, status); > return ret; > @@ -646,13 +717,75 @@ static int vhost_vdpa_get_config(struct vhost_dev *dev, uint8_t *config, > return ret; > } > > +static int vhost_vdpa_set_vring_dev_kick(struct vhost_dev *dev, > + struct vhost_vring_file *file) > +{ > + trace_vhost_vdpa_set_vring_kick(dev, file->index, file->fd); > + return vhost_vdpa_call(dev, VHOST_SET_VRING_KICK, file); > +} > + > +/** > + * Set the shadow virtqueue descriptors to the device > + * > + * @dev The vhost device model > + * @svq The shadow virtqueue > + * @idx The index of the virtqueue in the vhost device > + * @errp Error > + */ > +static bool vhost_vdpa_svq_setup(struct vhost_dev *dev, > + VhostShadowVirtqueue *svq, > + unsigned idx, > + Error **errp) > +{ > + struct vhost_vring_file file = { > + .index = dev->vq_index + idx, > + }; > + const EventNotifier *event_notifier = &svq->hdev_kick; > + int r; > + > + file.fd = event_notifier_get_fd(event_notifier); > + r = vhost_vdpa_set_vring_dev_kick(dev, &file); > + if (unlikely(r != 0)) { > + error_setg_errno(errp, -r, "Can't set device kick fd"); > + } > + > + return r == 0; > +} > + > +static bool vhost_vdpa_svqs_start(struct vhost_dev *dev) > +{ > + struct vhost_vdpa *v = dev->opaque; > + Error *err = NULL; > + unsigned i; > + > + if (!v->shadow_vqs) { > + return true; > + } > + > + for (i = 0; i < v->shadow_vqs->len; ++i) { > + VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i); > + bool ok = vhost_vdpa_svq_setup(dev, svq, i, &err); > + if (unlikely(!ok)) { > + error_reportf_err(err, "Cannot setup SVQ %u: ", i); > + return false; > + } > + } > + > + return true; > +} > + > static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started) > { > struct vhost_vdpa *v = dev->opaque; > + bool ok; > trace_vhost_vdpa_dev_start(dev, started); > > if (started) { > vhost_vdpa_host_notifiers_init(dev); > + ok = vhost_vdpa_svqs_start(dev); > + if (unlikely(!ok)) { > + return -1; > + } > vhost_vdpa_set_vring_ready(dev); > } else { > vhost_vdpa_host_notifiers_uninit(dev, dev->nvqs); > @@ -724,8 +857,16 @@ static int vhost_vdpa_get_vring_base(struct vhost_dev *dev, > static int vhost_vdpa_set_vring_kick(struct vhost_dev *dev, > struct vhost_vring_file *file) > { > - trace_vhost_vdpa_set_vring_kick(dev, file->index, file->fd); > - return vhost_vdpa_call(dev, VHOST_SET_VRING_KICK, file); > + struct vhost_vdpa *v = dev->opaque; > + int vdpa_idx = file->index - dev->vq_index; > + > + if (v->shadow_vqs_enabled) { > + VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, vdpa_idx); > + vhost_svq_set_svq_kick_fd(svq, file->fd); > + return 0; > + } else { > + return vhost_vdpa_set_vring_dev_kick(dev, file); > + } > } > > static int vhost_vdpa_set_vring_call(struct vhost_dev *dev,