From dff4426fa6562b6837ddc662a61836ae11ac4fae Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= Date: Mon, 14 Mar 2022 18:34:42 +0100 Subject: [PATCH] vhost: Add Shadow VirtQueue kick forwarding capabilities MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Pérez Acked-by: Michael S. Tsirkin Signed-off-by: Jason Wang --- hw/virtio/vhost-shadow-virtqueue.c | 55 +++++++++++ hw/virtio/vhost-shadow-virtqueue.h | 14 +++ hw/virtio/vhost-vdpa.c | 144 ++++++++++++++++++++++++++++- include/hw/virtio/vhost-vdpa.h | 4 + 4 files changed, 215 insertions(+), 2 deletions(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index c1db02c53e..e5da907b8e 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -11,6 +11,59 @@ #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. + * + * @n: guest kick event notifier, the one that guest set to notify svq. + */ +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); + 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 +92,7 @@ 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 +110,7 @@ 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-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/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index 6c67d5f034..9c7cb32bdd 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, @@ -445,8 +479,14 @@ static void vhost_vdpa_host_notifiers_uninit(struct vhost_dev *dev, int n) 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; @@ -460,6 +500,21 @@ 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; @@ -468,6 +523,7 @@ 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); @@ -559,11 +615,26 @@ 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; @@ -647,13 +718,74 @@ 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); @@ -725,8 +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, 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 + #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;