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: 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 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) (limited to 'hw/virtio/vhost-shadow-virtqueue.c') diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index c1db02c..e5da907 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); -- cgit v1.1